00503nas a2200145 4500008004100000245011900041210007100160300000900231490000700240100001600247700001700263700001400280700001700294856004600311 2023 eng d00aDynamic plant–herbivore interactions between bison space use and vegetation heterogeneity in a tallgrass prairie0 aDynamic plant–herbivore interactions between bison space use and a52690 v151 aLing, Bohua1 aRaynor, E.J.1 aJoern, A.1 aGoodin, D.G. uhttps://www.mdpi.com/2072-4292/15/22/526901392nas a2200133 4500008004100000245010600041210006900147490000700216520091600223100002101139700001401160700001801174856006601192 2022 eng d00aHow and why grasshopper community maturation rates are slowing on a North American tall grass prairie0 aHow and why grasshopper community maturation rates are slowing o0 v183 a

Invertebrate growth rates have been changing in the Anthropocene. We examine rates of seasonal maturation in a grasshopper community that has been declining annually greater than 2% a year over 34 years. As this grassland has experienced a 1°C increase in temperature, higher plant biomass and lower nutrient densities, the community is maturing more slowly. Community maturation had a nutritional component: declining in years/watersheds with lower plant nitrogen. The effects of fire frequency were consistent with effects of plant nitrogen. Principal components analysis also suggests associated changes in species composition—declines in the densities of grass feeders were associated with declines in community maturation rates. We conclude that slowed maturation rates—a trend counteracted by frequent burning—likely contribute to long-term decline of this dominant herbivore.

1 aKaspari, Michael1 aJoern, A.1 aWelti, E.A.R. uhttps://royalsocietypublishing.org/doi/10.1098/rsbl.2021.051000677nas a2200193 4500008004100000245013200041210006900173300001400242490000600256100001800262700001400280700002300294700002500317700001800342700002500360700002300385700002100408856005400429 2021 eng d00aStudies of insect temporal trends must account for the complex sampling histories inherent to many long-term monitoring efforts0 aStudies of insect temporal trends must account for the complex s a589–5910 v51 aWelti, E.A.R.1 aJoern, A.1 aEllison, Aaron, M.1 aLightfoot, David, C.1 aRecord, Sydne1 aRodenhouse, Nicholas1 aStanley, Emily, H.1 aKaspari, Michael uhttp://www.nature.com/articles/s41559-021-01424-000763nas a2200229 4500008004100000022001400041245012700055210006900182300001100251490000800262100002900270700001800299700002300317700002000340700002100360700001700381700001800398700002000416700001900436700001700455856006100472 2020 eng d a0012-965800aHarmony on the prairie? Grassland plant and animal community responses to variation in climate across land‐use gradients0 aHarmony on the prairie Grassland plant and animal community resp ae029860 v1011 aBruckerhoff, Lindsey, A.1 aConnell, Kent1 aGuinnip, James, P.1 aAdhikari, Elina1 aGodar, Alixandra1 aGido, K., B.1 aBoyle, W., A.1 aHope, Andrew, G1 aJoern, Anthony1 aWelti, Ellen uhttps://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.298602368nas a2200181 4500008004100000022001400041245009000055210006900145300001400214490000800228520178100236100002302017700002102040700002602061700001902087700002102106856005902127 2020 eng d a0027-842400aNutrient dilution and climate cycles underlie declines in a dominant insect herbivore0 aNutrient dilution and climate cycles underlie declines in a domi a7271-72750 v1173 a

Evidence for global insect declines mounts, increasing our need to understand underlying mechanisms. We test the nutrient dilution (ND) hypothesis—the decreasing concentration of essential dietary minerals with increasing plant productivity—that particularly targets insect herbivores. Nutrient dilution can result from increased plant biomass due to climate or CO2 enrichment. Additionally, when considering long-term trends driven by climate, one must account for large-scale oscillations including El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO). We combine long-term datasets of grasshopper abundance, climate, plant biomass, and end-of-season foliar elemental content to examine potential drivers of abundance cycles and trends of this dominant herbivore. Annual grasshopper abundances in 16- and 22-y time series from a Kansas prairie revealed both 5-y cycles and declines of 2.1–2.7%/y. Climate cycle indices of spring ENSO, summer NAO, and winter or spring PDO accounted for 40–54% of the variation in grasshopper abundance, mediated by effects of weather and host plants. Consistent with ND, grass biomass doubled and foliar concentrations of N, P, K, and Na—nutrients which limit grasshopper abundance—declined over the same period. The decline in plant nutrients accounted for 25% of the variation in grasshopper abundance over two decades. Thus a warming, wetter, more CO2-enriched world will likely contribute to declines in insect herbivores by depleting nutrients from their already nutrient-poor diet. Unlike other potential drivers of insect declines—habitat loss, light and chemical pollution—ND may be widespread in remaining natural areas.

1 aWelti, Ellen, A.R.1 aRoeder, Karl, A.1 ade Beurs, Kirsten, M.1 aJoern, Anthony1 aKaspari, Michael uhttp://www.pnas.org/lookup/doi/10.1073/pnas.192001211702743nas a2200217 4500008004100000245008300041210006900124490000700193520201500200653000902215653003002224653002302254653002002277653002602297653002102323100001302344700001702357700001702374700001902391856011502410 2019 eng d00aEffects of fire and large herbivores on canopy nitrogen in a tallgrass prairie0 aEffects of fire and large herbivores on canopy nitrogen in a tal0 v113 a

This study analyzed the spatial heterogeneity of grassland canopy nitrogen in a tallgrass prairie with different treatments of fire and ungulate grazing (long-term bison grazing vs. recent cattle grazing). Variogram analysis was applied to continuous remotely sensed canopy nitrogen images to examine the spatial variability in grassland canopies. Heterogeneity metrics (e.g., the interspersion/juxtaposition index) were calculated from the categorical canopy nitrogen maps and compared among fire and grazing treatments. Results showed that watersheds burned within one year had higher canopy nitrogen content and lower interspersions of high-nitrogen content patches than watersheds with longer fire intervals, suggesting an immediate and transient fire effect on grassland vegetation. In watersheds burned within one year, high-intensity grazing reduced vegetation density, but promoted grassland heterogeneity, as indicated by lower canopy nitrogen concentrations and greater interspersions of high-nitrogen content patches at the grazed sites than at the ungrazed sites. Variogram analyses across watersheds with different grazing histories showed that long-term bison grazing created greater spatial variability of canopy nitrogen than recent grazing by cattle. This comparison between bison and cattle is novel, as few field experiments have evaluated the role of grazing history in driving grassland heterogeneity. Our analyses extend previous research of effects from pyric herbivory on grassland heterogeneity by highlighting the role of grazing history in modulating the spatial and temporal distribution of aboveground nitrogen content in tallgrass prairie vegetation using a remote sensing approach. The comparison of canopy nitrogen properties and the variogram analysis of canopy nitrogen distribution provided by our study are useful for further mapping grassland canopy features and modeling grassland dynamics involving interplays among fire, large grazers, and vegetation communities.

10afire10agrassland canopy nitrogen10agrassland dynamics10agrazing history10aSpatial heterogeneity10aUngulate grazing1 aLing, B.1 aRaynor, E.J.1 aGoodin, D.G.1 aJoern, Anthony uhttps://www.mdpi.com/2072-4292/11/11/1364?fbclid=IwAR3lLrrJFA3JBzN5IcRlRx-Gn7S_f-9nclPRB4H7IdDHxYQe34Ric_mraDs02170nas a2200181 4500008004100000245009200041210007100133300001400204490000700218520157000225100002401795700001201819700002001831700001801851700002001869700001901889856008001908 2019 eng d00aFire, grazing and climate shape plant–grasshopper interactions in a tallgrass prairie0 aFire grazing and climate shape plant–grasshopper interactions in a735 - 7450 v333 a

1. Species interactions are integral to ecological community function, and the      structure of species interactions has repercussions for the consequences of species extinctions. Few studies  have examined the role of environmental factors in controlling species interaction networks across time.
2. We examined variation in plant–grasshopper network structural properties in response to three major grassland drivers: periodic fire, ungulate grazing and climate.
3. We sequenced a plant barcoding gene from extracted grasshopper gut contents to characterize diets of 26 grasshopper species. Resulting grasshopper species’ diets were combined with long‐term plant and grasshopper surveys to assemble plant–grasshopper networks across 13–19 years for six watersheds subjected to varying fire and grazing treatments.
4. Network modularity, generality and predicted grasshopper community robustness to plant species loss all increased in grazed watersheds. Temperature decreased predicted grasshopper community robustness to plant species loss.
5. Grasshopper communities were found to be vulnerable to climatic warming due to host plant loss. However, intermediate disturbance from ungulate grazers may maintain grasshopper diversity and buffer community robustness to species loss. Our results suggest that climate and disturbance shape the structure of ecological interaction networks and thus have many indirect effects on species persistence though direct effects on interaction partners.

1 aWelti, Ellen, A. R.1 aFan, Q.1 aTetreault, H.M.1 aUngerer, M.C.1 aBlair, John, M.1 aJoern, Anthony uhttps://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.1327202178nas a2200205 4500008004100000245010100041210006900142490000700211520149900218653002701717653001801744653002501762653001901787653002201806100001501828700001701843700002301860700001901883856007001902 2019 eng d00aHyperspectral analysis of leaf pigments and nutritional elements in tallgrass prairie vegetation0 aHyperspectral analysis of leaf pigments and nutritional elements0 v103 a

Understanding the spatial distribution of forage quality is important to address critical research questions in grassland science. Due to its efficiency and accuracy, there has been a widespread interest in mapping the canopy vegetation characteristics using remote sensing methods. In this study, foliar chlorophylls, carotenoids, and nutritional elements across multiple tallgrass prairie functional groups were quantified at the leaf level using hyperspectral analysis in the region of 470–800 nm, which was expected to be a precursor to further remote sensing of canopy vegetation quality. A method of spectral standardization was developed using a form of the normalized difference, which proved feasible to reduce the interference from background effects in the leaf reflectance measurements. Chlorophylls and carotenoids were retrieved through inverting the physical model PROSPECT 5. The foliar nutritional elements were modeled empirically. Partial least squares regression was used to build the linkages between the high-dimensional spectral predictor variables and the foliar biochemical contents. Results showed that the retrieval of leaf biochemistry through hyperspectral analysis can be accurate and robust across different tallgrass prairie functional groups. In addition, correlations were found between the leaf pigments and nutritional elements. Results provided insight into the use of pigment-related vegetation indices as the proxy of plant nutrition quality.

10aHyperspectral analysis10aLeaf pigments10aNutritional elements10aremote sensing10atallgrass prairie1 aLing, B.H.1 aGoodin, D.G.1 aRaynor, Edward, J.1 aJoern, Anthony uhttps://www.frontiersin.org/articles/10.3389/fpls.2019.00142/full02299nas a2200193 4500008004100000245011700041210007100158300001200229490000800241520165500249653002201904653001601926653002401942653001701966653001601983100002401999700001902023856006302042 2018 eng d00aFire and grazing modulate the structure and resistance of plant–floral visitor networks in a tallgrass prairie0 aFire and grazing modulate the structure and resistance of plant– a517-5280 v1863 a

Significant loss of pollinator taxa and their interactions with flowering plants has resulted in growing reductions to pollination services globally. Ecological network analysis is a useful tool for evaluating factors that alter the interaction structure and resistance of systems to species loss, but is rarely applied across multiple empirical networks sampled within the same study. The non-random arrangement of species interactions within a community, or “network structure” such as nested or modular organization, is predicted to prevent extinction cascades in ecological networks. How ecological gradients such as disturbance regimes shape network structural properties remains poorly understood despite significant efforts to quantify interaction structure in natural systems. Here, we examine changes in the structure of plant–floral visitor networks in a tallgrass prairie using a decadal and landscape-scale experiment that manipulates prescribed burn frequency and ungulate grazing, resulting in different grassland states. Plant and floral visitor communities and accompanying network structure were impacted by grassland fire and grazing regimes. The presence of grazers increased flowering plant species richness, network floral visitor species richness, and decreased network nestedness. Fire frequency affected flowering plant and floral visitor community composition; community composition impacted network specialization and modularity. Grassland state resulting from fire-grazing interactions has important implications for the resistance of flowering plant and floral visitor communities to species loss.

10aCommunity ecology10adisturbance10aEcological networks10aInteractions10aPollinators1 aWelti, Ellen, A. R.1 aJoern, Anthony uhttp://link.springer.com/article/10.1007/s00442-017-4019-902414nas a2200157 4500008004100000245010000041210006900141300001400210490000600224520187700230100002302107700002502130700001902155700001902174856006302193 2017 eng d00aComplex variation in habitat selection strategies among individuals driven by extrinsic factors0 aComplex variation in habitat selection strategies among individu a1802-18220 v73 a

Understanding behavioral strategies employed by animals to maximize fitness in the face of environmental heterogeneity, variability, and uncertainty is a central aim of animal ecology. Flexibility in behavior may be key to how animals respond to climate and environmental change. Using a mechanistic modeling framework for simultaneously quantifying the effects of habitat preference and intrinsic movement on space use at the landscape scale, we investigate how movement and habitat selection vary among individuals and years in response to forage quality–quantity tradeoffs, environmental conditions, and variable annual climate. We evaluated the association of dynamic, biotic forage resources and static, abiotic landscape features with large grazer movement decisions in an experimental landscape, where forage resources vary in response to prescribed burning, grazing by a native herbivore, the plains bison (Bison bison bison), and a continental climate. Our goal was to determine how biotic and abiotic factors mediate bison movement decisions in a nutritionally heterogeneous grassland. We integrated spatially explicit relocations of GPS-collared bison and extensive vegetation surveys to relate movement paths to grassland attributes over a time period spanning a regionwide drought and average weather conditions. Movement decisions were affected by foliar crude content and low stature forage biomass across years with substantial interannual variation in the magnitude of selection for forage quality and quantity. These differences were associated with interannual differences in climate and growing conditions from the previous year. Our results provide experimental evidence for understanding how the forage quality–quantity tradeoff and fine-scale topography drives fine-scale movement decisions under varying environmental conditions.

1 aRaynor, Edward, J.1 aBeyer, Hawthorne, L.1 aBriggs, J., M.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/full/10.1002/ece3.276401986nas a2200193 4500008004100000245012700041210006900168300001400237490000800251520130500259653002301564653003701587653003001624653003301654653002501687100001501712700001901727856004601746 2017 eng d00aDensity mediates grasshopper performance in response to temperature manipulation and spider predation in tallgrass prairie0 aDensity mediates grasshopper performance in response to temperat a261 - 2670 v1073 a

Species interactions are often context-dependent, where outcomes require an understanding of influences among multiple biotic and abiotic factors. However, it remains unclear how abiotic factors such as temperature combine with important biotic factors such as density-dependent food limitation and predation to influence species interactions. Using a native grassland - grasshopper - wolf spider model food chain in tallgrass prairie, we conducted a manipulative field experiment to examine how predator-prey interactions respond to manipulations of temperature, grasshopper density, and food chain length. We find that grasshopper performance responses to temperature and predator treatments were density dependent. At high densities, grasshopper survival decreased with increased temperature when no spiders were present. When spiders were present, grasshopper survival was reduced, and this effect was strongest in the cooled treatment. In contrast, grasshopper survival did not vary significantly with spider presence or among temperature treatments at low grasshopper densities. Our results indicate that context-dependent species interactions are common and highlight the importance of understanding how and when key biotic and abiotic factors combine to influence species interactions.

10adensity dependence10aKonza Prairie Biological Station10aPhoetaliotes nebrascensis10aRabidosa rabida; temperature10aSpecies interactions1 aLaws, A.N.1 aJoern, Anthony uhttps://doi.org/10.1017/S000748531600089402567nas a2200217 4500008004100000245005900041210005900100260004300159490002100202520191100223653002302134653001202157653001302169653001402182653001502196653002202211100002402233700001902257700002002276856005302296 2017 eng d00aEcological networks of grassland plants and arthropods0 aEcological networks of grassland plants and arthropods aManhattan, KSbKansas State University0 vPhD Dissertation3 a

Ecological communities are comprised both of species and their interactions. The importance of species interactions is embraced by ecological network analysis, a framework used to identify non-random patterns in species interactions, and the consequences of these patterns for maintaining species diversity. Here, I investigated environmental drivers of the structure of plant-pollinator and plant-herbivore networks. Specifically, I asked: (1) Do global-scale climate gradients shape mutualistic and antagonistic networks? (2) At a landscape scale (within a 3,487 ha research site), how do contrasting regimes of major grassland disturbances - fire frequency and grazing by bison (Bison bison) - shape plant-pollinator network structure? (3) How do fire and grazing affect plant-grasshopper network structure? And, (4) What is the role of plant species diversity in determining plant-herbivore network structure? At the global scale, variability in temperature was the key climatic factor regulating both antagonistic and mutualistic network structural properties. At the landscape scale, fire and grazing had major consequences for plant-pollinator and plant-herbivore communities. In particular, bison grazing increased network complexity and resistance to species loss for both plant-pollinator and plant-herbivore systems. Results from an experimental grassland restoration that manipulated plant diversity suggest that plant diversity directly affects plant-herbivore structure and increases network stability. Collectively, these results suggest that environmental gradients and plant species diversity regulate the network structure of ecological communities. Determining how the structure of ecological interactions change with environmental conditions and species diversity improves our ability to identify vulnerable communities, and to predict responses of biodiversity to global change.

10aEcological network10aecology10aFood web10aHerbivore10aPollinator10atallgrass prairie1 aWelti, Ellen, A. R.1 aJoern, Anthony1 aBlair, John, M. uhttp://krex.k-state.edu/dspace/handle/2097/3528402260nas a2200145 4500008004100000245009700041210006900138300001100207490000600218520176100224100001701985700001802002700001902020856007502039 2017 eng d00aImpacts of plant diversity on arthropod communities and plant-herbivore network architecture0 aImpacts of plant diversity on arthropod communities and planther ae019830 v83 a

At the local scale, insect herbivore diversity is often limited by plant diversity, but little is known about how the network structure of plant and herbivore interactions changes across local plant diversity gradients. Ascertaining plant–herbivore interaction structure at the ecological community level is important for predicting responses of herbivores to plant species loss. We sampled arthropods and plants across three years, beginning in the fourth year of an experimental prairie restoration containing three treatment levels of sown plant diversity. Plots initially planted with higher plant diversity had higher arthropod species richness. Sown diversity treatments strongly affected plant–herbivore interaction structure: The increased sown diversity treatment decreased plant–herbivore connectance, increased average herbivore diet generalism, and increased herbivore robustness to plant species loss. Treatments diverged over time with the last year of sampling showing the greatest difference between treatments in plant and arthropod species richness, and plant–herbivore network structural properties. Network structural properties of the high sown diversity treatment were the least variable temporally. However, divergence of plant and arthropod between diversity treatments was not found in traditional ordinations of community taxonomic composition. While previous comparisons of plant–herbivore interaction networks across ecological gradients treated network size (biodiversity) as a confounding factor, we demonstrate that plant diversity can directly shape network structure, and higher plant diversity maintains less temporally variable ecological networks of herbivores and their host plants.

1 aWelti, Ellen1 aHelzer, Chris1 aJoern, Anthony uhttps://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.198304432nas a2200193 4500008004100000245014500041210006900186260004300255490002100298520366600319653003403985653002204019653003704041653003904078653002104117100002804138700001904166856005304185 2017 eng d00aRole of spatial and temporal vegetation heterogeneity from fire-grazing interactions to the assembly of tallgrass prairie spider communities0 aRole of spatial and temporal vegetation heterogeneity from fireg aManhattan, KSbKansas State University0 vPhD Dissertation3 a

North American tallgrass prairie is a dynamic ecosystem that evolved with variable regimes of fire and grazing interactions (pyric herbivory), and variable mid-continental weather. Combined, these ecological factors create a shifting mosaic of plant communities that create heterogeneous and structurally complex habitats that move around across the landscape in time and space. The overarching goal of my dissertation was to study how bottom-up habitat templates created in response to fire-grazing interactions influence the community structure of spiders, key arthropod predators in grassland food-webs. Spiders are a ubiquitous and diverse group of terrestrial predators that partition their habitat at fine scales with species distributions and abundances that are sensitive to habitat structure. Primary hypotheses examined include: (H1) Spider density, species diversity, species evenness and functional richness of hunting strategies should increase as the spatial heterogeneity of habitat structure and overall habitat productivity increases, as predicted by the habitat complexity and heterogeneity hypothesis. (H2) Pyric herbivory indirectly determines spider community structure through is effect on vegetation structure and spatial heterogeneity, thereby promoting the formation of a mosaic of spider species assemblages that track changes in the distribution of key habitat resources. My research takes advantage of a long-term, watershed-level manipulations of fire frequency and bison grazing across a topographically variable landscape at Kansas State University’s Konza Prairie Biological Station, a tallgrass prairie research site near Manhattan KS. Spider communities were sampled for three years at 23 sites representative of multiple habitat types ranging from low-stature grass-dominated sites to grassland-gallery forest transition zones. In addition, a field experiment was performed to test the hypothesis that vegetation structure contributes directly to web-builder abundance and web-type richness of spiders in open grasslands. Here, the availability of structure for web placement was increased by adding dead woody stems along transects in three watersheds that differed in burn histories and existing habitat structure in the absence of grazing. Results were consistent with the three key hypotheses. Species diversity and the functional diversity of spiders increased as the spatial heterogeneity and overall structure of habitat increased in response to fire-grazing interactions. Vegetation heterogeneity influenced spider community responses most strongly in the summer. Structural complexity of vegetation influenced spider diversity, species evenness and richness of hunting strategies throughout the growing season, becoming most important by the end of the growing season. The transitional ecotone between grasslands and woodlands supported a hotspot for spider density, species diversity and richness of hunting strategies along vegetation gradients (H1), and among habitat types (H2). Increasing the availability of web-anchoring structures in open grasslands led to increased web-builder density in open grassland, particularly for small and medium sized orb-web species that took advantage of increased physical structure. Disturbance from pyric herbivory indirectly promoted dynamic and malleable assemblages of spider species that coexisted in syntopy through effects on vegetation structure and its availability in time and space. Changes in habitat structure and heterogeneity as spatially and temporally shifting mosaics of habitat type increased the overall spider diversity at the landscape scale.

10aFire and grazing interactions10ahabitat structure10aKonza Prairie Biological Station10aSpatial and temporal heterogeneity10aSpider community1 aGómez, Jesús, Enrique1 aJoern, Anthony uhttp://krex.k-state.edu/dspace/handle/2097/3467202673nas a2200181 4500008004100000245008000041210006900121490000600190520210100196100001702297700001902314700001702333700001502350700001902365700001502384700001702399856007502416 2017 eng d00aTemporal variability in large grazer space use in an experimental landscape0 aTemporal variability in large grazer space use in an experimenta0 v83 aLand use, climate change, and their interaction each have great potential to affect grazing systems. With anticipated more frequent and extensive future drought, a more complete understanding of the mechanisms that determine large grazer landscape-level distribution under varying climatic conditions is integral to ecosystem management. Using an experimental setting with contrasting fire treatments, we describe the inter-annual variability of the effect of landscape topography and disturbance from prescribed spring fire on large grazer space use in years of variable resource availability. Using GPS telemetry, we investigated space use of plains bison (Bison bison bison) as they moved among watersheds managed with variable experimental burn treatments (1-, 2-, 4-, and 20-year burn intervals) during a seven-year period spanning years of average-to-above average forage production and severe drought. At the landscape scale, bison more strongly favored high-elevation and recently burned watersheds with watersheds burned for the first time in 2 or 4 yr consistently showing higher use relative to annually burned watersheds. In particular, watersheds burned for the first time in 4 yr were avoided to lesser extent than other more frequently burned watersheds during the dormant season. This management type also maintained coupling between bison space use and post-fire regrowth across post-drought growing season months, whereas watersheds with more frequent fire-return intervals attracted bison in only the first month post-fire. Hence, fire frequency played a role in maintaining the coupling of grazer and post-fire regrowth, the fire–grazer interaction, in response to drought-induced reduction in fuel loads. Moreover, bison avoided upland habitat in poor forage production years, when forage regrowth is less likely to occur in upland than in lowland habitats. Such quantified responses of bison to landscape features can aid future conservation management efforts and planning to sustain fire–grazer interactions and resulting spatial heterogeneity in grassland ecosystems.1 aRaynor, E.J.1 aJoern, Anthony1 aSkibbe, A.M.1 aSowers, M.1 aBriggs, J., M.1 aLaws, A.N.1 aGoodin, D.G. uhttps://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.167401918nas a2200145 4500008004100000245008200041210006900123300001200192490000700204520145100211100001401662700001501676700001901691856006201710 2016 eng d00aCrab spiders (Thomisidae) attract insect flower-visitors without UV signaling0 aCrab spiders Thomisidae attract insect flowervisitors without UV a611-6170 v413 a

1. Crab spiders (Thomisidae) indirectly affect insect flower-visitor and flowering plant interactions by consuming and altering the behaviour of insects. 2. Although one expects insect flower-visitors to avoid crab spiders actively, some crab spider species are known to attract flower-visitors. Crab spiders may use UV signalling to lure potential prey to the flowers they occupy. 3. In the present study, a field experiment was conducted to examine the effects of crab spiders occupying three prairie plant species for the insect flower-visitor community. Pollinating insects were significantly attracted to inflorescences with crab spiders compared to inflorescences without crab spiders for two plant species, and herbivorous insects were attracted to inflorescences with crab spiders for one of these plant species. The two flowering plant species with increased pollinator visitation showed increased seed weights for plants with crab spiders, indicating crab spider presence indirectly increased pollination. 4. To test the UV signalling hypothesis, inflorescences with crab spiders of one plant species were observed under both a UV-blocking plastic and a clear plastic control. Contrary to our prediction, flower-visitors were not more likely to land on inflorescences under the clear plastic; the UV signalling hypothesis was not supported. Other unknown explanations underlie prey attraction to inflorescences with crab spiders.

1 aWelti, E.1 aPutnam, S.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/een.1233402240nas a2200157 4500008004100000245012900041210006900170300001700239490000600256520167900262100001701941700001901958700002301977700001902000856006302019 2016 eng d00aForaging decisions underlying restricted space use: effects of fire and forage maturation on large herbivore nutrient uptake0 aForaging decisions underlying restricted space use effects of fi a5843–5853 0 v63 a

Recent models suggest that herbivores optimize nutrient intake by selecting patches of low to intermediate vegetation biomass. We assessed the application of this hypothesis to plains bison (Bison bison) in an experimental grassland managed with fire by estimating daily rates of nutrient intake in relation to grass biomass and by measuring patch selection in experimental watersheds in which grass biomass was manipulated by prescribed burning. Digestible crude protein content of grass declined linearly with increasing biomass, and the mean digestible protein content relative to grass biomass was greater in burned watersheds than watersheds not burned that spring (intercept; F1,251 = 50.57, P < 0.0001). Linking these values to published functional response parameters, ad libitum protein intake, and protein expenditure parameters, Fryxell's (Am. Nat., 1991, 138, 478) model predicted that the daily rate of protein intake should be highest when bison feed in grasslands with 400–600 kg/ha. In burned grassland sites, where bison spend most of their time, availability of grass biomass ranged between 40 and 3650 kg/ha, bison selected foraging areas of roughly 690 kg/ha, close to the value for protein intake maximization predicted by the model. The seasonal net protein intake predicted for large grazers in this study suggest feeding in burned grassland can be more beneficial for nutrient uptake relative to unburned grassland as long as grass regrowth is possible. Foraging site selection for grass patches of low to intermediate biomass help explain patterns of uniform space use reported previously for large grazers in fire-prone systems.

1 aRaynor, E.J.1 aJoern, Anthony1 aNippert, Jesse, B.1 aBriggs, J., M. uhttps://onlinelibrary.wiley.com/doi/full/10.1002/ece3.230402435nas a2200217 4500008004100000022001400041245013100055210006900186300001200255490000700267520159500274653002201869653004401891653001001935653002201945653001401967100002301981700002102004700001902025856017302044 2016 eng d a0161-820200aImportance of vegetation structure to the assembly of an aerial web-building spider community in North American open grassland0 aImportance of vegetation structure to the assembly of an aerial  a28 - 350 v443 a

Spatial and temporal heterogeneity of suitable habitat in grasslands can promote species and functional diversity in arthropods, including responses by ubiquitous web-building spiders. A field experiment in tallgrass prairie habitat was performed to examine the response in abundance and web-type richness of aerial web-building spiders to changes in the availability of structure for web placement (vegetation architecture). To test the hypothesis that vegetation structure contributes directly to the web-builder abundance and web-type richness in open grasslands, we increased vegetation structure by adding dead woody stems of a common shrub along transects in each of three watersheds that differed in burn histories and existing habitat structure. Aerial web-building spiders were visually censused before and after the manipulations, at which time we recorded web-orientation, height, web-type, and the presence/absence of the spider associated with a web. Over the duration of the study, a total of seven web-type groups were encountered, of which medium-sized orb weavers were the most abundant web-building group across all watersheds. In general, higher spider abundances of orb-building spiders were observed in sections with added structure compared to the non-manipulated sections. However, reduced richness of web types was found on the manipulated sections of transects, suggesting that the architecture provided by woody stems does not provide sufficient and appropriate web-anchoring structure for the full range of web-building spiders groups in tallgrass prairie.

10ahabitat structure10aheterogeneity–biodiversity hypothesis10aKonza10atallgrass prairie10aWeb types1 aGómez, Jesús, E.1 aLohmiller, Jenny1 aJoern, Anthony uhttps://bioone.org/journals/The-Journal-of-Arachnology/volume-44/issue-1/P14-58.1/Importance-of-vegetation-structure-to-the-assembly-of-an-aerial/10.1636/P14-58.1.short02957nas a2200145 4500008004100000245008700041210006900128300001500197490000700212520246300219100001702682700001902699700001902718856007402737 2015 eng d00aBison foraging responds to fire frequency in nutritionally heterogeneous grassland0 aBison foraging responds to fire frequency in nutritionally heter a1586 -15970 v963 a

Foraging decisions by native grazers in fire-dependent landscapes modulate the fire–grazing interaction. Uncovering the behavioral mechanisms associated with the attraction of grazers to recently burned areas requires understanding at multiple spatial scales in the ecological foraging hierarchy. This study focused on feeding in the area between steps in a foraging bout, the feeding station, as forage chemistry and vegetation architecture play central roles in these fine-scale, feeding-station decisions. The forage maturation hypothesis (FMH) uses the temporal dynamics of forage quality and quantity in grasslands to explain the distribution of large herbivores, but does not address herbivore responses to inter-patch variation caused by fire-induced nutrient increases of forage quality. Using an experimental setting with contrasting fire treatments we describe the effects of variable burn history on foraging kinetics by bison at Konza Prairie Biological Station (KPBS). We assessed the potential to link the FMH in a complementary fashion to the transient maxima hypothesis (TMH) to explain temporal variation in bison responses to grassland forage quality and quantity in response to burning at different temporal frequencies. Forage attributes met predictions of the TMH that allowed us to investigate how forage maturation affects feeding station foraging behavior across watersheds with varying burn frequency. At sites burned in the spring after several years without burning, both bite mass and intake rate increased with increasing biomass at a greater rate during the growing season than during the transitional midsummer seasonal period. In these infrequently burned watersheds, early growing season bite mass (0.6 ± 0.05 g; mean ± SE), bite rate (38 ± 1.5 bites/min), and intake rate (21 ± 2.3 g/min) was reduced by ~15%, 13%, and 29% during the midsummer transitional period. A behavioral response in foraging kinetics at the feeding station occurred where a nonequilibrial pulse of high-quality resource was made available and then retained by repeated grazing over the growing season. Our results provide the first experimental evidence for demonstrating the fine-scale behavioral response of a large grazer to fire-induced changes in forage attributes, while linking two prominent hypotheses proposed to explain spatial variation in forage quality and quantity at local and landscape scales.

1 aRaynor, E.J.1 aJoern, Anthony1 aBriggs, J., M. uhttps://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/14-2027.103435nas a2200157 4500008004100000245010900041210006900150260004300219490002200262520274400284653008703028100001703115700001903132700001903151856010703170 2015 eng d00aEcological hierarchy of foraging in a large herbivore: the plains bison perspective in tallgrass prairie0 aEcological hierarchy of foraging in a large herbivore the plains aManhattan, KSbKansas State University0 vPhD. Dissertation3 a

Foraging decisions by native grazers in fire-dependent landscapes reflect fire-grazing interactions. I assessed behavioral responses associated with the attraction of grazers to recently burned areas at multiple spatial scales. (a) I focused on feeding in the area between steps in a foraging bout – the feeding station – where forage quality and vegetation architecture underlie these fine-scale decisions. The ‘forage maturation hypothesis’ (FMH) predicts the distribution of large herbivores based on the temporal dynamics of forage quality and quantity, but does not address herbivore responses to inter-patch variation caused by fire-induced increases of forage quality. The ‘transient maxima hypothesis’ (TMH) also predicts variable forage quality and quantity, but in response to intermittent disturbance from fire. I described the effects of variable spring burn history to bison foraging and their spatio-temporal distribution at Konza Prairie. Forage attributes met predictions of the TMH to explain how forage maturation affects foraging behavior across watersheds with varying burn frequency. At sites burned in the spring after several years without burning, intake rate increased with increasing vegetation biomass at a greater rate during the early growing season than during the transitional mid-summer period. This foraging behavior occurred in response to a non-equilibrial pulse of high quality resource that set the stage in the burned area, and was then retained by repeated grazing over the growing season. Thus, bison responded increased forage resource availability resulting from transient maxima in infrequently-burned watersheds burned that spring and they intensely used these areas until forage availability and forage regrowth was not possible. (b) At the patch scale, bison selected areas of low-to-moderate grass cover in which to feed and avoided areas of high forb cover in the growing season. During the dormant season, however, bison selected feeding-sites with uniformly high canopy cover in watersheds that were not burned. (c) At the landscape-scale, infrequently burned watersheds (compared to watersheds that were not burned) provided the strongest significant predictor of bison space use in all early growing- and transitional-season months. (d) The probability of habitat selection was driven by availability of high foliar, protein and low-to-intermediate herbaceous biomass throughout the growing season. These results explain the hierarchy of foraging by a dominant consumer in an experimental landscape by linking two prominent hypotheses, TMH-FMH, proposed to explain spatial variation in forage quality and quantity at local and landscape scales.

10aBison; Foraging Behavior; Forage Maturation; Movement; Space Use; Transient Maxima1 aRaynor, E.J.1 aJoern, Anthony1 aBriggs, J., M. uhttp://krex.k-state.edu/dspace/bitstream/handle/2097/20348/EdwardRaynor2015.pdf?sequence=1&isAllowed=y02172nas a2200145 4500008004100000245015400041210006900195300001300264490000800277520161600285100002801901700001901929700001601948856006201964 2015 eng d00aInvertebrate, not small vertebrate, herbivory interacts with nutrient availability to impact tallgrass prairie community composition and forb biomass0 aInvertebrate not small vertebrate herbivory interacts with nutri a842 -8500 v1243 a

The effects of herbivores and their interactions with nutrient availability on primary production and plant community composition in grassland systems is expected to vary with herbivore type. We examined the effects of invertebrate and small vertebrate herbivores and their interactions with nutrient availability on grassland plant community composition and aboveground biomass in a tallgrass prairie ecosystem. The abundance of forbs relative to grasses increased with invertebrate herbivore removals. This increase in forb abundance led to a shift in community composition, where invertebrate removals resulted in greater plant species evenness as well as a divergence in composition among plots. In contrast, vertebrate herbivore removals did not affect plant community composition or aboveground biomass. Nutrient additions alone resulted in a decrease in plant species richness and an increase in the abundance of the dominant grass, but the dominant grass species did not greatly increase in abundance when nutrient additions were combined with invertebrate removals. Rather, several subdominant forbs came to dominate the plant community. Additionally, the combined nutrient addition and invertebrate herbivore removal treatment increased forb biomass, suggesting that invertebrate herbivores suppress the responses of forb species to chronic nutrient additions. Overall, the release of forbs from invertebrate herbivore pressure may result in large shifts in species composition, with consequences for aboveground biomass and forage quality due to altered grass:forb ratios in grassland systems.

1 aLa Pierre, Kimberly, J.1 aJoern, Anthony1 aSmith, M.D. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/oik.0186901724nas a2200145 4500008004100000245008700041210006900128300001300197490000600210520123900216653002501455100001601480700001901496856006301515 2015 eng d00aStructure of trophic and mutualistic networks across broad environmental gradients0 aStructure of trophic and mutualistic networks across broad envir a326 -3340 v53 a

This study aims to understand how inherent ecological network structures of nestedness and modularity vary over large geographic scales with implications for community stability. Bipartite networks from previous research from 68 locations globally were analyzed. Using a meta-analysis approach, we examine relationships between the structure of 22 trophic and 46 mutualistic bipartite networks in response to extensive gradients of temperature and precipitation. Network structures varied significantly across temperature gradients. Trophic networks showed decreasing modularity with increasing variation in temperature within years. Nestedness of mutualistic networks decreased with increasing temperature variability between years. Mean annual precipitation and variability of precipitation were not found to have significant influence on the structure of either trophic or mutualistic networks. By examining changes in ecological networks across large-scale abiotic gradients, this study identifies temperature variability as a potential environmental mediator of community stability. Understanding these relationships contributes to our ability to predict responses of biodiversity to climate change at the community level.

10atrophic interactions1 aWelti, E.L.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/full/10.1002/ece3.137102866nas a2200229 4500008004100000245010900041210006900150300001100219490000700230520206600237653001402303653004302317653002302360653003902383653002402422653002202446653003102468100001602499700001902515700001902534856008302553 2015 eng d00aWeather affects grasshopper population dynamics in continental grassland over annual and decadal periods0 aWeather affects grasshopper population dynamics in continental g a29 -390 v683 a

Understanding the complex dynamics of insect herbivores requires consideration of both exogenous and endogenous factors at multiple temporal scales. This problem is difficult due to differences in population responses among closely related taxa. Increased understanding of dynamic relationships between exogenous and endogenous factors will facilitate forecasting and suggest nodes in the life cycle of economically important species susceptible to intervention by managers. This study uses an information-theoretic approach to examine the contributions of weather and density to model population densities and growth rates of nine common grasshopper species from continental U.S. grassland over 25 years. In general, grass-feeding species and total grass-feeders as a functional group were most closely associated with weather during the year before hatching. Increased variability in prior growing season precipitation was associated with increased densities of Mermiria bivittata, Opeia obscura, Phoetaliotes nebrascensis, and the grass-feeding guild. Melanoplus sanguinipes densities tended to be smaller following warm fall seasons, while Amphitoruns coloradus declined during the positive phase of the North Atlantic Oscillation or after warmer than average winters. Population growth rate dynamics of all grouped species combinations were best explained by models including variability in precipitation during the prior year growing season. Large-scale Pacific Decadal Oscillation (PDO) patterns were also associated with growth rate dynamics of the mixed-feeding species group. Density showed a negative relationship with population growth rates of five species. This study indicates the importance of parental and diapause environmental conditions and the utility of incorporating long-term, readily obtained decadal weather indices for forecasting grasshopper densities and identifying critical years with regard to grasshopper management—at least to the degree that the past will continue to predict the future as global climates change.

10aacrididae10aatmospheric oscillations (NAO PDO SOI)10adensity dependence10aexogenous and endogenous feedbacks10agrasshopper control10ainsect herbivores10apopulation growth rate (R)1 aJonas, J.L.1 aWolesensky, W.1 aJoern, Anthony uhttps://www.sciencedirect.com/science/article/pii/S1550742414000128?via%3Dihub02079nas a2200205 4500008004100000245013700041210006900178300001500247490000600262520139700268653002501665653003301690653002301723100001501746700001701761700001701778700001501795700001901810856004401829 2014 eng d00aEstimating canopy nitrogen content in a heterogeneous grassland with varying fire and grazing treatments: Konza Prairie, Kansas, USA0 aEstimating canopy nitrogen content in a heterogeneous grassland  a4430 -44530 v63 a

Quantitative, spatially explicit estimates of canopy nitrogen are essential for understanding the structure and function of natural and managed ecosystems. Methods for extracting nitrogen estimates via hyperspectral remote sensing have been an active area of research. Much of this research has been conducted either in the laboratory, or in relatively uniform canopies such as crops. Efforts to assess the feasibility of the use of hyperspectral analysis in heterogeneous canopies with diverse plant species and canopy structures have been less extensive. In this study, we use in situ and aircraft hyperspectral data to assess several empirical methods for extracting canopy nitrogen from a tallgrass prairie with varying fire and grazing treatments. The remote sensing data were collected four times between May and September in 2011, and were then coupled with the field-measured leaf nitrogen levels for empirical modeling of canopy nitrogen content based on first derivatives, continuum-removed reflectance and ratio-based indices in the 562–600 nm range. Results indicated that the best-performing model type varied between in situ and aircraft data in different months. However, models from the pooled samples over the growing season with acceptable accuracy suggested that these methods are robust with respect to canopy heterogeneity across spatial and temporal scales.

10aheterogeneous canopy10ahyperspectral remote sensing10anitrogen estimates1 aLing, B.H.1 aGoodin, D.G.1 aMohler, R.L.1 aLaws, A.N.1 aJoern, Anthony uhttps://www.mdpi.com/2072-4292/6/5/443002394nas a2200313 4500008004100000245009600041210006900137300001300206490000700219520149500226653001601721653001401737653001201751653001501763653001201778653002001790653001201810653002201822653001901844653002101863653002701884100001701911700002101928700001801949700001801967700001701985700001902002856005902021 2013 eng d00aBlazing and grazing: influences of fire and bison on tallgrass prairie stream water quality0 aBlazing and grazing influences of fire and bison on tallgrass pr a779 -7910 v323 a

Fire and grazers (such as Bison bison) were historically among the most important agents for maintaining and managing tallgrass prairie, but we know little about their influences on water-quality dynamics in streams. We analyzed 2 y of data on total suspended solids (TSS), total N (TN), and total P (TP) (3 samples per week per stream during flow) in 3 prairie streams with fire and bison grazing treatments at Konza Prairie Biological Station, Kansas (USA), to assess whether fire and bison increase the concentrations of these water-quality variables. We quantified the spatial and temporal locations of bison (∼0.21 animal units/ha) with Global Positioning System collars and documented bison trails, paw patches, wallows, and naturally exposed sediment patches within riparian buffers. Three weeks post-fire, TN and TP decreased (t-test, p < 0.001), but TSS did not change. Bison spent <6% of their time within 10 m of the streams, increased the amount of exposed sediment in the riparian areas, and avoided wooded mainstem branches of stream (χ2 test, p < 0.001). Temporal trends suggest that low discharge or increased bison density in the stream may increase TSS and TP during the summer months. Our results indicate a weak connection between TSS and nutrients with bison access to streams over our 2-y study and indicate that low TSS and nutrients characterize tallgrass prairie streams with fire and moderate bison densities relative to surrounding land uses.

10aBison bison10aBos bison10aburning10aGrasslands10agrazers10aprescribed fire10astreams10atallgrass prairie10atotal nitrogen10atotal phosphorus10atotal suspended solids1 aLarson, D.M.1 aGrudzinski, B.P.1 aDodds, W., K.1 aDaniels, M.D.1 aSkibbe, A.M.1 aJoern, Anthony uhttps://www.journals.uchicago.edu/doi/10.1899/12-118.101824nas a2200229 4500008004100000245009200041210006900133300001100202490000800213520112800221653001401349653001701363653002401380653001601404653002601420653002401446653001501470653001201485100001601497700001901513856006201532 2013 eng d00aDietary selection and nutritional regulation in a common mixed-feeding insect herbivore0 aDietary selection and nutritional regulation in a common mixedfe a20 -260 v1483 a

The geometric framework provides a way for understanding the multi-dimensional nutritional relationships between consumers and their food. We use this approach to further our understanding of the feeding and nutritional ecology of a ubiquitous mixed-feeding insect herbivore that consumes a variety of host plants spanning a wide range of nutritional composition. Our overall objective was to examine feeding decisions, resulting performance, and post-ingestive consequences in a common mixed-feeding insect herbivore, Melanoplus bivittatus (Say) (Orthoptera: Acrididae), when presented with paired diets differing in protein:carbohydrate (p:c) ratio. Intake p:c of M. bivittatus differed among all but two treatments and in many cases was farther than expected from the previously identified p:c intake target for this species. Despite this variability in intake of protein and carbohydrate, we found few effects of the diet treatments on performance or post-ingestive processing. However, our results suggest that when feeding on high-quality diets, nutrients consumed in excess may be stored rather than excreted.

10aacrididae10acarbohydrate10ageometric framework10ahomeostasis10aMelanoplus bivittatus10anutritional ecology10aOrthoptera10aprotein1 aJonas, J.L.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/eea.1206501423nas a2200133 4500008004100000245007900041210006900120300001100189490000700200520097700207100001901184700001301203856007301216 2013 eng d00aEcological mechanisms underlying arthropod species diversity in grasslands0 aEcological mechanisms underlying arthropod species diversity in  a19 -360 v583 a

Arthropods are an important component of grassland systems, contributing significantly to biodiversity and ecosystem structure and function. Climate, fire, and grazing by large herbivores are important drivers in grasslands worldwide. Arthropod responses to these drivers are highly variable and clear patterns are difficult to find, but responses are largely indirect with respect to changes in resources, species interactions, habitat structure, and habitat heterogeneity resulting from interactions among fire, grazing, and climate. Here, we review these ecological mechanisms influencing grassland arthropod diversity. We summarize hypotheses describing species diversity at local and regional scales and then discuss specific factors that may affect arthropod diversity in grassland systems. These factors include direct and indirect effects of grazing, fire, and climate, species interactions, above- and belowground interactions, and landscape-level effects.

1 aJoern, Anthony1 aLaws, A. uhttps://www.annualreviews.org/doi/10.1146/annurev-ento-120811-15354001883nas a2200169 4500008004100000245007400041210006900115300001300184490000800197520135700205100001801562700002001580700001901600700001401619700001901633856006101652 2013 eng d00aGenetic variation and mating success in managed American plains bison0 aGenetic variation and mating success in managed American plains  a182 -1910 v1043 a

The American plains bison (Bison bison) was pushed to the brink of extinction in the late 1800s but has since rebounded. Less than 5% of animals currently exist in conservation herds that are critical for maintaining genetic variability. Here, we use 25 microsatellite loci to assess genetic diversity and patterns of mating success over a 3-year period in a managed conservation herd at Konza Prairie Biological Station, Kansas (total number of individuals genotyped = 587). Heterozygosity was comparable to and allelic diversity higher than that in 11 other wild and managed herds for which similar estimates are available. Parentage analyses revealed that males within the oldest age classes (5–7 years) sired >90% of calves over the study period, consistent with a polygynous breeding system. Asymmetries in siring success also were observed within age classes, with the same males enjoying high siring success over multiple seasons. Empirical results of paternity will facilitate future modeling and empirical efforts to determine how demographic factors, population size, and variation in siring success interact to determine the retention (or loss) of genetic diversity in natural and managed herds, thus allowing informed recommendations for management practices and conservation efforts of this symbolic North American species.

1 aUngerer, M.C.1 aWeitekamp, C.A.1 aJoern, Anthony1 aTowne, G.1 aBriggs, J., M. uhttps://academic.oup.com/jhered/article/104/2/182/80210502310nas a2200349 4500008004100000245005700041210005600098300001300154490000700167520136700174653001701541653002501558653001901583653002401602653002301626653001201649653001801661653001901679100001801698700001501716700001301731700001501744700001401759700001601773700001701789700001901806700001801825700002001843700001601863700001901879856006201898 2013 eng d00aInvertebrates, ecosystem services and climate change0 aInvertebrates ecosystem services and climate change a327 -3480 v883 a

The sustainability of ecosystem services depends on a firm understanding of both how organisms provide these services to humans and how these organisms will be altered with a changing climate. Unquestionably a dominant feature of most ecosystems, invertebrates affect many ecosystem services and are also highly responsive to climate change. However, there is still a basic lack of understanding of the direct and indirect paths by which invertebrates influence ecosystem services, as well as how climate change will affect those ecosystem services by altering invertebrate populations. This indicates a lack of communication and collaboration among scientists researching ecosystem services and climate change effects on invertebrates, and land managers and researchers from other disciplines, which becomes obvious when systematically reviewing the literature relevant to invertebrates, ecosystem services, and climate change. To address this issue, we review how invertebrates respond to climate change. We then review how invertebrates both positively and negatively influence ecosystem services. Lastly, we provide some critical future directions for research needs, and suggest ways in which managers, scientists and other researchers may collaborate to tackle the complex issue of sustaining invertebrate-mediated services under a changing climate.

10aBiodiversity10abioindicator species10aClimate change10aecosystem engineers10aecosystem services10ainsects10ainvertebrates10asustainability1 aPrather, C.M.1 aPelini, S.1 aLaws, A.1 aRivest, E.1 aWoltz, M.1 aBloch, C.P.1 aDel Toro, I.1 aHo, Chuan-Kai.1 aKominoski, J.1 aNewbold, T.A.S.1 aParsons, S.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/brv.1200202308nas a2200193 4500008004100000245011400041210006900155300001300224490000800237520165000245653001401895653002101909653001601930653004001946653002701986100001602013700001902029856006602048 2013 eng d00aLife history traits associated with body size covary along a latitudinal gradient in a generalist grasshopper0 aLife history traits associated with body size covary along a lat a379 -3910 v1743 a

Animal body size often varies systematically along latitudinal gradients, where individuals are either larger or smaller with varying season length. This study examines ecotypic responses by the generalist grasshopper Melanoplus femurrubrum (Orthoptera: Acrididae) in body size and covarying, physiologically based life history traits along a latitudinal gradient with respect to seasonality and energetics. The latitudinal compensation hypothesis predicts that smaller body size occurs in colder sites when populations must compensate for time constraints due to short seasons. Shorter season length requires faster developmental and growth rates to complete life cycles in one season. Using a common garden experimental design under laboratory conditions, we examined how grasshopper body size, consumption, developmental time, growth rate and metabolism varied among populations collected along an extended latitudinal gradient. When reared at the same temperature in the lab, individuals from northern populations were smaller, developed more rapidly, and showed higher growth rates, as expected for adaptations to shorter and generally cooler growing seasons. Temperature-dependent, whole organism metabolic rate scaled positively with body size and was lower at northern sites, but mass-specific standard metabolic rate did not differ among sites. Total food consumption varied positively with body size, but northern populations exhibited a higher mass-specific consumption rate. Overall, compensatory life history responses corresponded with key predictions of the latitudinal compensation hypothesis in response to season length.

10aacrididae10aDevelopment time10aGrowth rate10aLatitudinal compensation hypothesis10aMelanoplus femurrubrum1 aParsons, S.1 aJoern, Anthony uhttps://link.springer.com/article/10.1007%2Fs00442-013-2785-606383nas a2200157 4500008004100000245009700041210006900138260003000207520582200237100001706059700001906076700001606095700001906111700001706130856007806147 2012 eng d00aInsect herbivore outbreaks views through a physiological framework: insights from Orthoptera0 aInsect herbivore outbreaks views through a physiological framewo bAcademic Press, San Diego3 a

Insect herbivore outbreaks, particularly orthopteran outbreaks, have plagued humans throughout recorded history. The Egyptian locust swarm described in the Old Testament is perhaps the most famous orthopteran outbreak story. Two species, the African desert locust (Schistocerca gregaria Forskål) and the migratory locust (Locusta migratoria (Linnaeus)), still outbreak regularly throughout large expanses of Africa and the Middle East. The most likely villain in the biblical swarm was the African desert locust, based on the broad array of the food plants described in the story. In contrast to the desert locust, the migratory locust is a specialist that feeds only on grasses. However, despite its restricted diet, the migratory locust has a larger geographic range, extending from all of northern and central Africa across to eastern China. It too has greatly impacted human society throughout historical time, especially in China. Parenthetically, the Chinese character for locust is composed of two parts, insect (虫) and emperor (皇); this character combination indicates the power of locusts – it was an insect capable of threatening an emperor’s supremacy. In China’s 5000-year history, 842 locust plagues have been recorded, with the earliest ones being described in the Book of Songs (770–476 BCE). How locust outbreaks endangered regimes and changed the destiny of China is also described in two other important ancient Chinese books – Zizhi Tongjian (which covers Chinese history from 403 BCE to 959 CE, including 16 dynasties) and Ch’ien Han Shu (which covers Chinese history from 206 BCE to 25 CE). Although the recorded histories of Australia and the Americas are more recent, orthopteran outbreaks have a long history on these continents as well. The first recorded outbreak of the Australian plague locust (Chortoicetes terminifera (Walker)) was in 1844, followed by outbreaks from the 1870s onward (including multiple outbreaks in the early 2000s, most of which were controlled by the Australian Plague Locust Commission (Hunter 2004)). In the United States, massive outbreaks of the Rocky Mountain locust (Melanoplus spretus (Walsh)) were recorded in the 1870s. The largest of the swarms covered a “swath equal to the combined areas of Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island and Vermont” (Riley et al. 1880), and nearly derailed westward expansion. Charles Valentine Riley, now considered one of the founding fathers of entomology in the United States, was appointed by the US government to investigate these outbreaks. His work led him to request further federal assistance, which the government provided in the form of the US Entomological Commission; this agency quickly morphed into the US Department of Agriculture that still operates today. The last known Rocky Mountain locust swarm occurred in the very early 1900s; why it disappeared remains a mystery, although some interesting hypotheses have been proposed (Lockwood 2005). The Mormon cricket (Anabrus simplex (Haldeman)) is another orthopteran species renowned for its outbreaks. Populations of Mormon crickets usually occur at low densities throughout most of their range in western North America, but population explosions that exceed more than 1 million individuals, marching in roving bands at densities of more than 100 individuals/m2 , are not uncommon. In 1848 a Mormon cricket outbreak nearly thwarted the settlement of Salt Lake City, Utah, by Mormon pioneers. Although the story is controversial, Mormon folklore recounts the miracle of the gulls. Legend claims that legions of seagulls, sent by God, appeared on June 9, 1848. These seagulls saved the settler’s crops by eating all the crickets. South America and Central America also have orthopterans that show outbreak dynamics, the most notable being Schistocerca cancellata (Serville) and Schistocerca piceifrons (Walker), respectively. Given the devastation and immense suffering inflicted on humans by orthopteran outbreaks, it is pressing to understand the causal factors that contribute to their outbreaks. With the exception of Mormon crickets (see Sword 2005), the orthopterans described above exhibit phase polyphenism – defined by Hardie and Lees (1985, 473) as “occurrence of two or more distinct phenotypes which can be induced in individuals of the same genotype by extrinsic factors.” The African desert locust and African migratory locust are easily two of the best-known species to practice phase polyphenism. However, many orthopterans that do not exhibit phase polyphenism can also undergo outbreaks, as has been the case for many grasshopper species in the western United States (Branson et al. 2006). In this chapter we concentrate primarily on orthopterans, but our aim is to understand factors that contribute to insect herbivore outbreaks more generally. We also discuss other types of insects, particularly lepidopterans, to make our points. Because insect outbreaks cannot happen without an initial increase in population size, we begin by focusing on individuals while considering factors, especially nutritional ones, that contribute to increased performance. We next explore how behavior and performance (e.g., survival, growth, and reproduction) of individual insect herbivores change as population densities increase. Shifting gears, we then discuss how ecological paradigms, particularly the “plant stress hypothesis,” have influenced how we view insect herbivore outbreaks. We conclude the chapter by calling for an integrative approach that translates individual responses into group-level phenomena, couched within the contexts of their communities and ecosystems.

1 aBehmer, S.T.1 aJoern, Anthony1 aBarbosa, P.1 aLetourneau, D.1 aAgrawaal, A. uhttp://behmerlab.tamu.edu/Resources/Behmer%20%26%20Joern%20(IOR-2012).pdf02406nas a2200133 4500008004100000245009600041210006900137300001300206490000800219520193600227100001302163700001902176856007702195 2012 eng d00aPredator-prey interactions in a grassland food chain vary with temperature and food quality0 aPredatorprey interactions in a grassland food chain vary with te a977 -9860 v1223 a

Because species interactions are often context-dependent, abiotic factors such as temperature and biotic factors such as food quality may alter species interactions with potential consequences to ecosystem structure and function. For example, altered predator–prey interactions may influence the dynamics of trophic cascades, affecting net primary production. In a three-year field experiment, we manipulated a plant–grasshopper–spider food chain in mesic tallgrass prairie to investigate the effects of temperature and food quality on grasshopper performance, and to understand the direct and indirect tritrophic interactions that contribute to trophic cascades. Because spiders are active at cooler temperatures than grasshoppers in our system, we hypothesized that predator effects would be strongest in cooled treatments, and weakest in warmed treatments. Grasshopper spider interactions were highly context-dependent and varied significantly with food quality, temperature treatment and year. Spiders most often reduced grasshopper survival in the cooled and ambient temperature treatments, but had little to no effect on grasshopper survival in the warmed treatments, as hypothesized. In some years, plants compensated for grasshopper herbivory and trophic cascades were not observed despite significant effects of predators on grasshopper survival. However, in the year they were observed, trophic cascades only occurred in cooled treatments where predator effects on grasshoppers were strongest. Predicting ecosystem responses to climate change will require an understanding of how temperature influences species interactions. Our results demonstrate that changes in daily temperature regimes can alter predator–prey interactions among arthropods with consequences for ecosystem processes such as primary production and the relative importance of top–down and bottom–up processes.

1 aLaws, A.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2012.20419.x02565nas a2200205 4500008004100000245011800041210006900159300001300228490000800241520171600249653001401965653001201979653003301991653003702024653001502061653001702076100001302093700001902106856023402125 2012 eng d00aVariable effects of dipteran parasitoids and management treatment on grasshopper fecundity in a tallgrass prairie0 aVariable effects of dipteran parasitoids and management treatmen a123 -1300 v1023 a

Grasshoppers host a number of parasitoids, but little is known about their impact on grasshopper life history attributes or how those impacts may vary with land use. Here, we report on a three-year survey of nine grasshopper species in a tallgrass prairie managed with fire and bison grazing treatments. We measured parasitoid prevalence and the impact of parasitoid infection on grasshopper fecundity to determine if grasshopper-parasitoid interactions varied with management treatment. Adult female grasshoppers were collected every three weeks from eight watersheds managed with different prescribed burning and grazing treatments. Grasshopper fecundity with and without parasitoids was estimated through dissections of reproductive tracts. Dipteran parasitoids from two families (Nemestrinidae and Tachinidae) were observed infecting grasshoppers. We found significant effects of grazing treatment, but not burn interval, on grasshopper-parasitoid interactions. Parasitoids were three times more abundant in watersheds with bison grazing than in ungrazed watersheds, and the relative abundance of nemestrinid and tachinid flies varied with grazing treatment. Parasitoid prevalence varied among grasshopper species from <0.01% infected (Mermiria bivittata) to 17% infected (Hypochlora alba). Parasitoid infection reduced individual grasshopper fecundity, with stronger effects on current reproduction than on past reproduction. Furthermore, current fecundity in parasitized grasshoppers was lower in grazed watersheds compared to ungrazed watersheds. Nemestrinid parasitoids generally had stronger impacts on grasshopper fecundity than tachinid parasitoids, the effects of which were more variable.

10agrassland10aGrazing10ahost-parasitoid interactions10aKonza Prairie Biological Station10aOrthoptera10areproduction1 aLaws, A.1 aJoern, Anthony uhttps://www.cambridge.org/core/journals/bulletin-of-entomological-research/article/variable-effects-of-dipteran-parasitoids-and-management-treatment-on-grasshopper-fecundity-in-a-tallgrass-prairie/EB1AD93DB7D975E1009489797D88DF2E03097nas a2200205 4500008004100000245012700041210006900168260004300237490001400280520240300294653001402697653002502711653002702736653002402763653001602787653001602803100001602819700001902835856003702854 2011 eng d00aA generalist grasshopper species (Melanoplus femurrubrum) is adapted to variable environments along a latitudinal gradient0 ageneralist grasshopper species Melanoplus femurrubrum is adapted aManhattan, KSbKansas State University0 vMS Thesis3 a

Temperature and food quality vary across broad latitudinal gradients, greatly affecting performance by insect herbivores. The contribution of each varies latitudinally so that geographically distinct populations are challenged by differences in nutritional needs and energetic demands. While there has been extensive work studying diet selectivity and nutritional ecology of insect herbivores, few studies have focused on how insect herbivores adapt across such vast environmental gradients. The generalist-feeding grasshopper, Melanoplus femurrubrum (DeGreer), has a broad geographic range that extends across much of North America, making this species ideal for comparative investigations of intrinsic performance responses to extensive but predictable patterns of environmental variation. I compared responses by six populations collected from populations located from Texas to North Dakota (USA) using a common garden experimental design to investigate clinal responses in grasshopper performance. I examined responses in: (1) body size, (2) thermoregulation and adaptive coloration, (3) developmental and growth rates, (4) metabolic rates, (5) total consumption and rates, (6) diet ratio selection, and (7) digestive processing efficiencies across the latitudinal gradient. Grasshopper body size followed the Converse Bergmann’s Rule with decreasing body size as latitude increased. Temperature influenced all other responses, but responses to diet were not always significant or directional. Latitudinal trends for development and growth rates were observed but mass-specific metabolic rates were similar for all populations. Total consumption was body size dependent but independent of diet type. Mass-specific consumption varied but no single directional trend was detected. There was a shift in carbohydrate-biased diet preference at low latitude toward protein-biased diet ratios at higher latitudes, suggesting adaptations to different energetic demands by these populations. However, post-ingestive (digestive) efficiencies demonstrated variable responses with northern populations observing highest efficiencies for some indices but not all. Overall, this research documents phenotypic plasticity to environmental variability to some degree for digestive efficiencies, but ecotypic responses in body size and diet preference among M. femurrubrum populations were observed.

10abody size10alatitudinal gradient10aMelanoplus femurrubrum10anutritional ecology10aPerformance10aTemperature1 aParsons, S.1 aJoern, Anthony uhttp://hdl.handle.net/2097/1309302323nas a2200193 4500008004100000245007900041210006900120300001300189490000700202520169800209653003701907653001701944653001501961653001501976653001701991100001302008700001902021856008902040 2011 eng d00aGrasshopper fecundity responses to grazing and fire in a tallgrass prairie0 aGrasshopper fecundity responses to grazing and fire in a tallgra a979 -9880 v403 a

Grasshopper abundance and diversity vary with management practices such as fire and grazing. Understanding how grasshopper life history traits such as fecundity respond to management practices is key to predicting grasshopper population dynamics in heterogeneous environments. Landscape-level experimental fire and bison grazing treatments at the Konza Prairie Biological Station (Manhattan, KS) provide an opportunity to examine how management affects grasshopper fecundity. Here we report on grasshopper fecundity for nine common species at Konza Prairie. From 2007 to 2009, adult female grasshoppers were collected every 3 wk from eight watersheds that varied in fire and grazing treatments. Fecundity was measured by examining female reproductive tracts, which contain a record of past and current reproductive activity. Body size was a poor predictor of fecundity for all species. Despite large differences in vegetation structure and composition with management regime (grazing and fire interval), we observed little effect of management on grasshopper fecundity. Habitat characteristics (grasshopper density, vegetation biomass, and vegetation quality; measured in 2008 and 2009) were better predictors of past fecundity than current fecundity, with species-specific responses. Fecundity increased throughout the summer, indicating that grasshoppers were able to acquire sufficient nutritional resources for egg production in the early fall when vegetation quality is generally low. Because fecundity did not vary across management treatments, population stage structure may be more important for determining population level reproduction than management regime at Konza Prairie.

10aKonza Prairie Biological Station10alife-history10amanagement10aOrthoptera10areproduction1 aLaws, A.1 aJoern, Anthony uhttps://academic.oup.com/ee/article-abstract/40/5/979/412531?redirectedFrom=fulltext02410nas a2200169 4500008004100000245011000041210006900151300001500220490000700235520184100242100001602083700001402099700001902113700001402132700001702146856007702163 2010 eng d00aComparative genome scan detects host-related divergent selection in the grasshopper Hesperotettix viridis0 aComparative genome scan detects hostrelated divergent selection  a4012 -40280 v193 a

In this study, we used a comparative genome scan to examine patterns of population differentiation with respect to host plant use in Hesperotettix viridis, a Nearctic oligophagous grasshopper locally specialized on various Asteraceae including Solidago, Gutierrezia, and Ericameria. We identified amplified fragment length polymorphism (AFLP) loci with significantly elevated FST (outlier loci) in multiple different-host and same-host comparisons of populations while controlling for geographic distance. By comparing the number and identities of outlier loci in different-host vs. same-host comparisons, we found evidence of host plant-related divergent selection for some population comparisons (Solidago- vs. Gutierrezia-feeders), while other comparisons (Ericameria- vs. Gutierrezia-feeders) failed to demonstrate a strong role for host association in population differentiation. In comparisons of Solidago- vs. Gutierrezia-feeding populations, a relatively high number of outlier loci observed repeatedly in different-host comparisons (35% of all outliers and 2.7% of all 625 AFLP loci) indicated a significant role for host-related selection in contributing to overall genomic differentiation in this grasshopper. Mitochondrial DNA sequence data revealed a star-shaped phylogeny with no host- or geography-related structure, low nucleotide diversity, and high haplotype diversity, suggesting a recent population expansion. mtDNA data do not suggest a long period of isolation in separate glacial refugia but are instead more compatible with a single glacial refugium and more recent divergence in host use. Our study adds to research documenting heterogeneity in differentiation across the genome as a consequence of divergent natural selection, a phenomenon that may occur as part of the process of ecological speciation.

1 aApple, J.L.1 aGrace, T.1 aJoern, Anthony1 aAmand, P.1 aWisely, S.M. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-294X.2010.04792.x02672nas a2200325 4500008004100000245014900041210006900190300001300259490000800272520162800280653001401908653002601922653002301948653002301971653003101994653001602025653002002041653003102061653002702092653002802119653002102147653001302168100001402181700001502195700001902210700001702229700001602246700001802262856006602280 2010 eng d00aDivergent host plant adaptation drives the evolution of reproductive isolation in the grasshopper Hesperotettix viridis (Orthoptera: Acrididae)0 aDivergent host plant adaptation drives the evolution of reproduc a866 -8780 v1003 a

Early stages of lineage divergence in insect herbivores are often related to shifts in host plant use and divergence in mating capabilities, which may lead to sexual isolation of populations of herbivorous insects. We examined host preferences, degree of differentiation in mate choice, and divergence in cuticular morphology using near-infrared spectroscopy in the grasshopper Hesperotettix viridis aiming to understand lineage divergence. In Kansas (USA), H. viridis is an oligophagous species feeding on Gutierrezia and Solidago host species. To identify incipient mechanisms of lineage divergence and isolation, we compared host choice, mate choice, and phenotypic divergence among natural grasshopper populations in zones of contact with populations encountering only one of the host species. A significant host-based preference from the two host groups was detected in host-paired feeding preference studies. No-choice mate selection experiments revealed a preference for individuals collected from the same host species independent of geographic location, and little mating was observed between individuals collected from different host species. Female mate choice tests between males from the two host species resulted in 100% fidelity with respect to host use. Significant differentiation in colour and cuticular composition of individuals from different host plants was observed, which correlated positively with host choice and mate choice. No evidence for reinforcement in the zone of contact was detected, suggesting that divergent selection for host plant use promotes sexual isolation in this species.

10aallopatry10aecological speciation10afeeding preference10agenetic divergence10ahost-associated divergence10amate choice10aMicrosatellites10anear-infrared spectroscopy10areproductive isolation10asecondary contact zones10asexual isolation10asympatry1 aGrace, T.1 aDowell, F.1 aJoern, Anthony1 aWisely, S.M.1 aBrown, S.J.1 aMaghirang, E. uhttps://academic.oup.com/biolinnean/article/100/4/866/245053702057nas a2200217 4500008004100000245015100041210006900192300001300261490000700274520127900281653002401560653002901584653002101613653001801634653003301652653002701685100001501712700001601727700001901743856007701762 2010 eng d00aGrasshoppers (Orthoptera: Acrididae) select vegetation patches in local-scale responses to foliar nitrogen but not phosphorus in native grassland0 aGrasshoppers Orthoptera Acrididae select vegetation patches in l a533 -5400 v183 a

Key elements such as nitrogen (N) and phosphorus (P) are often limiting relative to the nutritional needs of herbivores that feed on them. While N often limits insect herbivores in natural terrestrial ecosystems, the effect of P is poorly studied in the field, even though compelling hypotheses from the ecological stoichiometry literature predict its importance. We evaluated small-scale spatial distributions of, and herbivory by, grasshoppers among neighboring plots that vary in foliar-N and -P in tallgrass prairie. Grasshopper densities were 67% greater in N-fertilized plots but detected no effect to grasshopper densities from P-fertilizer. Leaf damage to the dominant grass Andropogon gerardii was 32% greater in N-fertilized plots, but no response to foliar-P was detected. Herbivore damage to a common forb, goldenrod (Solidago missouriensis), was not strongly linked by fertilizer treatments, although there was increased leaf damage in N-fertilizer treatments when no P was applied (a significant N × P interaction). Under field conditions at local scales, we conclude that spatially heterogeneous distributions of grasshoppers are primarily affected by foliar-N in host plants with little evidence that P-levels contribute to the spatial patterns.

10aAndropogon gerardii10aecological stoichiometry10ainsect herbivory10aKonza Prairie10aN-P fertilization experiment10aSolidago missouriensis1 aLoaiza, V.1 aJonas, J.L.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1744-7917.2010.01376.x02011nas a2200157 4500008004100000245009000041210006900131300001300200490000700213520148500220100001701705700001601722700001901738700001901757856007701776 2009 eng d00aConsequences of climate variability for the performance of bison in tallgrass prairie0 aConsequences of climate variability for the performance of bison a772 -7790 v153 a

Climate variability is a major structuring factor in grassland ecosystems, yet there is great uncertainty in how changes in precipitation affect grazing herbivores. We determined how interannual variation in the timing and magnitude of precipitation affected the weight gain of free-roaming bison in their first and second year. Bison weights were analyzed for 14 years for Konza Prairie, Kansas, and 12 years for Tallgrass Prairie Preserve, Oklahoma. Greater late-summer precipitation increased bison weight gain. For every 100 mm precipitation, weight gain increased 6.4–15.3 kg depending on age classes and site. In contrast, greater midsummer precipitation decreased weight gain. For every additional 100 mm precipitation, weight decreased 9.7–17.3 kg depending on age class and site. The decreased weight gain of bison with greater midsummer precipitation was associated with increased grass stem production during the period for each of three dominant grasses at Konza Prairie. Although greater stem production increases the quantity of aboveground biomass, it should decrease the overall nutritional quality of biomass to grazers, which would reduce weight gain. With offsetting effects of mid- and late-summer precipitation on weight gain, these results show that predicting the effects of climate change on grazers must incorporate both the timing and magnitude of changes in precipitation and their effects on both the quantity and quality of biomass.

1 aCraine, J.M.1 aTowne, E.G.1 aJoern, Anthony1 aHamilton, R.G. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01769.x01984nas a2200229 4500008004100000245010600041210006900147300001100216490000700227520109300234653002601327653003101353653002101384653002701405653002601432100001401458700001901472700001601491700001601507700001701523856021401540 2009 eng d00aHighly polymorphic microsatellites in the North American snakeweed grasshopper, Hesperotettix viridis0 aHighly polymorphic microsatellites in the North American snakewe a19 -210 v183 a

Microsatellite markers are preferred for fine-scale population genetic studies requiring high resolution. The grasshopper Hesperotettix viridis (Thomas) is an oligophagous species that feeds on composites and often exhibits locally restricted diets. Divergence in host plant use in some localities is seen where co-occurring subpopulations select alternate plant species, as expected with the evolution of host shifts and associated lineage divergence. To characterize the host-associated divergence patterns among populations of H. viridis, we developed markers from two microsatellite-enriched genomic libraries. Here we report the characterization and optimization of seven polymorphic di- and tri-nucleotide microsatellite loci for this species. One hundred and six individuals from 5 populations were tested for polymorphism. The number of alleles varied from 4 to 38 in all the populations. Ho ranged from 0.339 to 0.790. Homozygote excess was observed across loci, perhaps due to inbreeding. This is the first report of microsatellite markers for the subfamily Melanoplinae.

10aHesperotettix viridis10ahost-associated divergence10alocal adaptation10amicrosatellite markers10asnakeweed grasshopper1 aGrace, T.1 aJoern, Anthony1 aBrown, S.J.1 aApple, J.L.1 aWisely, S.M. uhttps://bioone.org/journals/Journal-of-Orthoptera-Research/volume-18/issue-1/034.018.0111/Highly-Polymorphic-Microsatellites-in-the-North-American-Snakeweed-Grasshopper-iHesperotettix/10.1665/034.018.0111.full02058nas a2200193 4500008004100000245007800041210006900119300001500188490000800203520146400211653001701675653001601692653002401708653002601732653002601758100001701784700001901801856004401820 2008 eng d00aCoexisting generalist herbivores occupy unique nutritional feeding niches0 aCoexisting generalist herbivores occupy unique nutritional feedi a1977 -19820 v1053 a

A mainstay of ecological theory and practice is that coexisting species use different resources, leading to the local development of biodiversity. However, a problem arises for understanding coexistence of multiple species if they share critical resources too generally. Here, we employ an experimental framework grounded in nutritional physiology to show that closely related, cooccurring and generalist-feeding herbivores (seven grasshopper species in the genus Melanoplus; Orthoptera: Acrididae) eat protein and carbohydrate in different absolute amounts and ratios even if they eat the same plant taxa. The existence of species-specific nutritional niches provides a cryptic mechanism that helps explain how generalist herbivores with broadly overlapping diets might coexist. We also show that performance by grasshoppers allowed to mix their diets and thus regulate their protein–carbohydrate intake matched optimal performance peaks generated from no-choice treatments. These results indicate the active nature of diet selection to achieve balanced diets and provide buffering capacity in the face of variable food quality. Our empirical findings and experimental approach can be extended to generate and test predictions concerning the intensity of biotic interactions between species, the relative abundance of species, yearly fluctuations in population size, and the nature of interactions with natural enemies in tritrophic niche space.

10aBiodiversity10aCompetition10ageometric framework10aphysiological ecology10aresource partitioning1 aBehmer, S.T.1 aJoern, Anthony uhttps://www.pnas.org/content/105/6/197701910nas a2200205 4500008004100000245011800041210006900159300001300228490000700241520120000248653004901448653002301497653002401520653002401544653003001568100001501598700001601613700001901629856005601648 2008 eng d00aDoes dietary-P affect feeding and performance in the mixed-feeding grasshopper (Acrididae) Melanoplus bivitattus?0 aDoes dietaryP affect feeding and performance in the mixedfeeding a333 -3390 v373 a

Although consequences of limited dietary protein and carbohydrate to performance are well studied for terrestrial insect herbivores, the importance of phosphorus (P) remains poorly understood. We examined the significance of dietary P to performance in fifth-instar nymphs of the grasshopper Melanoplus bivittatus fed artificial diets. Consumption, digestion, developmental rate, and growth in response to different levels of P nested within standard-Protein and carbohydrate diets were determined. Developmental rate was slowest on high-P diets; protein:carbohydrate concentration and P in diets affected frass production and consumption. Approximate digestibility and conversion of digested food were primarily influenced by the protein:carbohydrate quality of the diet but not P. Mass gain was marginally lower in the low-Protein:high carbohydrate diet used in this study. At the individual level, other than small effects to developmental rate at high concentrations for M. bivittatus, dietary P otherwise seems to have little effect on nymphal performance. To the degree that it is important, effects of dietary P depend on the concentrations of protein and carbohydrate in the diet.

10adietary phosphorus limitation to grasshopper10amultiple nutrients10anutritional ecology10anutritional indices10asecological stoichiometry1 aLoaiza, V.1 aJonas, J.L.1 aJoern, Anthony uhttps://academic.oup.com/ee/article/37/2/333/49853502631nas a2200253 4500008004100000245013600041210006900177300001300246490000700259520178500266653003002051653003002081653001502111653001602126653001702142653002102159653002602180653001902206653001802225653002202243100001602265700001902281856007702300 2008 eng d00aHost-plant quality alters grass/forb consumption by a mixed-feeding insect herbivore, Melanoplus bivittauts (Orthoptera: Acrididae)0 aHostplant quality alters grassforb consumption by a mixedfeeding a546 -5540 v333 a

1. Factors affecting the nutritional ecology of mixed-feeding, polyphagous herbivores are poorly understood. Mixed-feeding herbivores do better when they consume both forb and grass species although they typically feed primarily on forbs, which are of relatively higher protein content than grasses. 2. In a field experiment, we examined the effects of nitrogen and phosphorus fertilization and associated changes in host-plant C:N:P on proportional grass consumption by a mixed-feeding insect herbivore, Melanoplus bivittatus, using natural abundance stable carbon isotope (12C/13C) methods. We also examined a grass-feeding (Phoetaliotes nebrascensis) and forb-feeding (Hesperotettix viridis) species. 3. The C isotope signatures of M. bivittatus collected from plots fertilized with nitrogen (+N), phosphorus (+P), nitrogen and phosphorus (+N+P) and no fertilizer were compared with the C isotope signatures of plants in those plots to determine the proportion of assimilated C derived from C4 grasses and C3 forbs in each plot. We also examined the relationship between M. bivittatus diets and plant C:N:P stoichiometry. 4. The proportion of grass assimilated approximately doubled in N-fertilized treatments (39.1 ± 0.1%) compared with non-fertilized treatments (19 ± <0.1%), an increase associated with decreased C:N and increased N:P of grasses. 5. These results indicate that mixed-feeding M. bivittatus can selectively feed to balance C:N:P intake even when choosing between two structurally and chemically different groups of plants. 6. The strong relationship between diet selection and grass stoichiometry also suggests that plant nutrient composition may be more important than defensive chemistry in food choice.

10aC3 photosynthetic pathway10aC4 photosynthetic pathway10aCarbon (C)10agrasshopper10anitrogen (N)10aoptimal foraging10aOrthoptera: Acrididae10aphosphorus (P)10astoichiometry10atallgrass prairie1 aJonas, J.L.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2311.2008.01004.x01877nas a2200253 4500008004100000245008500041210006900126300001500195490000700210520104900217653002401266653003301290653001501323653001401338653003801352653002301390653002201413653001001435100001601445700001701461700001601478700001901494856011001513 2007 eng d00aConsumptionof mycorrhizal and saprophytic fungi by Collembola in grassland soils0 aConsumptionof mycorrhizal and saprophytic fungi by Collembola in a2594 -26020 v393 aAlthough soil-dwelling Collembola can influence plant growth and nutrient cycling, their specific role in soil food webs is poorly understood. Soil-free microcosm studies suggest that Collembola are primarily fungivores where they feed preferentially on saprophytic fungi (SF) over other fungal types. We directly assessed collembolan consumption of arbuscular mycorrhizal fungi (AMF) and SF using plant–soil mesocosms and natural abundance stable carbon isotope techniques. Mycorrhizal Andropogon gerardii (C4 grass) seedlings were placed in pots containing Collembola and soil from a C3 plant dominated site, while mycorrhizal Pascopyrum smithii (C3 grass) seedlings were placed in pots with Collembola and soil collected at a C4 plant dominated site. After 6 weeks, collembolans assimilated carbon derived from C3 and C4 sources in both A. gerardii and P. smithii treatments. Comparing Collembola isotope values in AMF vs. AMF-suppressed treatments, our data show that both AMF and SF were consumed in these experimental soil environments.10aAndropogon gerardii10aArbuscular mycorrhizal fungi10aCollembola10agrassland10aNatural abundance stable isotopes10aPascopyrum smithii10aSaprophytic fungi10aδ13C1 aJonas, J.L.1 aWilson, G.T.1 aWhite, P.M.1 aJoern, Anthony uhttp://knz.lternet.edu/content/consumptionof-mycorrhizal-and-saprophytic-fungi-collembola-grassland-soils02681nas a2200193 4500008004100000245014900041210006900190300001300259490000800272520199400280653001902274653002302293653001802316653004202334653001202376100001602388700001902404856006402423 2007 eng d00aGrasshopper (Orthoptera: Acrididae) communities respond to fire, bison grazing and weather in North Americantallgrass prairie: A long-term study0 aGrasshopper Orthoptera Acrididae communities respond to fire bis a699 -7110 v1533 a

Because both intrinsic and extrinsic factors influence insect population dynamics, operating at a range of temporal and spatial scales, it is difficult to assess their contributions. Long-term studies are ideal for assessing the relative contributions of multiple factors to abundance and community dynamics. Using data spanning 25 years, we investigate the contributions of weather at annual and decadal scales, fire return interval, and grazing by bison to understand the dynamics of abundance and community composition in grasshopper assemblages from North American continental grassland. Each of these three primary drivers of grassland ecosystem dynamics affects grasshopper population and community dynamics. Negative feedbacks in abundances, as expected for regulated populations, were observed for all feeding guilds of grasshoppers. Abundance of grasshoppers did not vary in response to frequency of prescribed burns at the site. Among watersheds that varied with respect to controlled spring burns and grazing by bison, species composition of grasshopper assemblages responded significantly to both after 25 years. However, after more than 20 years of fire and grazing treatments, the number of years since the last fire was more important than the managed long-term fire frequency per se. Yearly shifts in species composition (1983–2005), examined using non-metric multidimensional scaling and fourth-corner analysis, were best explained by local weather events occurring early in grasshopper life cycles. Large-scale patterns were represented by the Palmer Drought Severity Index and the North Atlantic Oscillation (NAO). The NAO was significantly correlated with annual mean frequencies of grasshoppers, especially for forb- and mixed-feeding species. Primary grassland drivers—fire, grazing and weather—contributing both intrinsic and extrinsic influences modulate long-term fluctuations in grasshopper abundances and community taxonomic composition.

10aFire frequency10aInsect populations10aKonza Prairie10aLong-Term Ecological Research Program10aWeather1 aJonas, J.L.1 aJoern, Anthony uhttps://link.springer.com/article/10.1007/s00442-007-0761-801403nas a2200193 4500008004100000245009300041210006900134300001100203490000600214520074700220653001900967653001700986653001601003653001401019100001601033700001901049700001901068856012201087 2007 eng d00aInsect development under predation risk, variable temperature, and variable food quality0 aInsect development under predation risk variable temperature and a47 -650 v43 aWe model the development of an individual insect, a grasshopper, through its nymphal period as a function of a trade-off between prey vigilance and nutrient intake in a changing environment. Both temperature and food quality may be variable. We scale up to the population level using natural mortality and a predation risk that is mass, vigilance, and temperature dependent. Simulations reveal the sensitivity of both survivorship and development time to risk and nutrient intake, including food quality and temperature variations. The model quantifies the crucial role of temperature in trophic interactions and development, which is an important issue in assessing the effects of global climate change on complex environmental interactions.10aeco-physiology10agrasshoppers10aTemperature10avigilance1 aLogan, J.D.1 aWolesensky, W.1 aJoern, Anthony uhttp://knz.lternet.edu/content/insect-development-under-predation-risk-variable-temperature-and-variable-food-quality00470nas a2200121 4500008004100000245010900041210006900150260004300219490002100262100001600283700001400299856003500313 2007 eng d00aNutrient resources and stoichiometry affect the ecology of above- and belowground invertebrate consumers0 aNutrient resources and stoichiometry affect the ecology of above aManhattan, KSbKansas State University0 vPhD Dissertation1 aJonas, J.L.1 aJoern, A. uhttp://hdl.handle.net/2097/40401965nas a2200205 4500008004100000245011300041210006900154300001300223490000700236520118700243653002201430653002501452653003101477653004001508653003201548100001801580700001901598700001601617856012601633 2006 eng d00aSustainable management of insect herbivores in grassland ecosystems: new perspectives in grasshopper control0 aSustainable management of insect herbivores in grassland ecosyst a743 -7550 v563 aGrasshoppers are insect herbivores common to grassland ecosystems worldwide. They comprise important components of biodiversity, contribute significantly to grassland function, and periodically exhibit both local and large-scale outbreaks. Because of grasshoppers' potential economic importance as competitors with ungulate grazers for rangeland forage, periodic grasshopper outbreaks in western US rangeland often elicit intervention over large areas in the form of chemical control. Available information combined with alternative underlying conceptual frameworks suggests that new approaches for sustainable management of grasshopper outbreaks in US rangeland should be pursued. There are many reasons to believe that approaches to grasshopper management that aim to reduce or prevent outbreaks are possible. These habitat manipulation tactics maintain existing ecological feedbacks responsible for sustaining populations at economically nonthreatening levels. Sustainable strategies to minimize the likelihood and extent of grasshopper outbreaks while limiting the need for chemical intervention are a rational and attainable goal for managing grasslands as renewable resources.10aGrassland ecology10ahabitat manipulation10ainsect population dynamics10aprevention of grasshopper outbreaks10asustainable pest management1 aBranson, D.H.1 aJoern, Anthony1 aSword, G.A. uhttp://knz.lternet.edu/content/sustainable-management-insect-herbivores-grassland-ecosystems-new-perspectives-grasshopper02110nas a2200205 4500008004100000245007200041210006900113300001300182490000800195520145400203653001701657653002001674653001401694653002701708653001601735100001601751700001901767700001901786856009901805 2006 eng d00aTemperature- dependent phenology and predation in arthropod systems0 aTemperature dependent phenology and predation in arthropod syste a471 -4820 v1963 aA central issue in ecology is to determine how environmental variations associated with global climate change, especially changing temperatures, affect trophic interactions in various ecosystems. This paper develops a temperature-dependent, stage-based, discrete, cohort model of the population dynamics of an insect pest under pressure from a predator. Guided by experimental data, the model is applied specifically to predation of grasshoppers by rangeland lycosid spiders. The development rate of insect arthropods is strongly affected by temperature, and these temperature-dependent phenological effects couple with shifts in the daily activity periods for both prey and predator, thereby increasing or decreasing opportunities for interaction. The model addresses these effects quantitatively by introducing a temperature-dependent, joint-activity factor that enters the predator’s functional response. The model also includes a prey mortality rate that is temperature-dependent through the prey development rate. The model is parameterized using field and experimental data for spiders and grasshoppers. We investigate the effect of the solar power index (sunlight), mean temperature, and temperature variation, as measured by amplitude, on the developmental times and survivorship both with, and without, predation. We conclude that increasing variation in temperature results in a stronger relative effect on survivorship due to predation.10agrasshoppers10aLycosid spiders10aphenology10aPredator–prey models10aTemperature1 aLogan, J.D.1 aWolesensky, W.1 aJoern, Anthony uhttp://knz.lternet.edu/content/temperature-dependent-phenology-and-predation-arthropod-systems02905nas a2200121 4500008004100000245013000041210006900171300001300240490000700253520238200260100001902642856012202661 2005 eng d00aLong-term disturbance from fire and bison grazing modulates grasshopper species assemblages (Orthoptera) in tallgrass prairie0 aLongterm disturbance from fire and bison grazing modulates grass a861 -8730 v863 aUnderstanding determinants of local species diversity remains central to developing plans to preserve biodiversity. In the continental United States, climate, grazing by large mammals, fire, and topography are important ecosystem drivers that structure North American tallgrass prairie, with major impacts on plant community composition and vegetation structure. Frequency of fire and grazing by bison (Bos bison), through effects on plant community composition and altered spatial and structural heterogeneity of vegetation in tallgrass prairie, may act as bottom-up processes that modulate insect community species richness. As previously seen for plant species richness, I hypothesized that grazing had more impact than fire frequency in determining species richness of insect herbivore communities. I examined this prediction with grasshoppers at Konza Prairie, a representative tallgrass prairie site in which fire frequency and bison grazing are manipulated over long terms with landscape-level treatments. Topographic position (upland vs. lowland) and fire frequency (1-, 2-, 4-year intervals, and unburned) did not significantly influence grasshopper species richness or indices of diversity, while grazing had significant effects. On average, I found ∼45% more grasshopper species and significantly increased values of Shannon H′ diversity at sites with bison grazing. Species abundances were more equally distributed (Shannon's Evenness Index) in grazed sites as well. No significant interactions among burning and grazing treatments explained variation in grasshopper species diversity. Grasshopper species richness responded positively to increased heterogeneity in vegetation structure and plant species richness, and negatively to average canopy height and total grass biomass. Variation in forb biomass did not influence grasshopper species richness. A significant positive relationship between grasshopper species richness and overall grasshopper density was observed. Species richness increased marginally as watershed area of treatments in grazed areas increased, but not in ungrazed areas. Disturbance from ecosystem drivers operating at watershed spatial scales exhibits strong effects on local arthropod species diversity, acting indirectly by mediating changes in the spatial heterogeneity of local vegetation structure and plant species diversity.1 aJoern, Anthony uhttp://knz.lternet.edu/content/long-term-disturbance-fire-and-bison-grazing-modulates-grasshopper-species-assemblages01989nas a2200181 4500008004100000245011200041210006900153300001500222490000700237520132500244653001801569653001801587653001501605653002401620653002301644100001901667856012101686 2004 eng d00aVariability in grasshopper densities in response to fire frequency and bison grazing from tallgrass prairie0 aVariability in grasshopper densities in response to fire frequen a1617 -16250 v333 aWhile weather can contribute significantly to grasshopper population dynamics in North American grasslands, local environmental conditions resulting from land use practices may be equally important. In this study, significant differences in grasshopper density were detected among adjacent watersheds from Kansas Flint Hills tallgrass prairie that differed in fire frequency and especially bison grazing treatments. Grasshopper densities were ≈2.5 times greater in grazed watersheds compared with ungrazed ones. Grasshopper densities also varied somewhat in response to fire frequency, mostly in species-specific ways. No treatment interactions on overall grasshopper density were detected. The effects of fire frequency and bison grazing were implemented in part through their combined effect on the structural heterogeneity of vegetation, and other habitat characteristics. Individual grasshopper species responded uniquely to combinations of fire frequency and bison grazing. Grazing resulted in significant increases in density for seven of the nine most abundant species; fire frequency affected two species; and one species did not respond to either fire or grazing. Understanding effects of habitat on grasshopper densities provides opportunities to manage these populations for economic or conservation needs.10aBison grazing10aKonza Prairie10aOrthoptera10apopulation dynamics10aprescribed burning1 aJoern, Anthony uhttp://knz.lternet.edu/content/variability-grasshopper-densities-response-fire-frequency-and-bison-grazing-tallgrass00476nas a2200145 4500008004100000245004700041210004700088260002800135300001300163100002400176700001600200700001900216700001700235856007800252 1995 eng d00aGrassland ecosystem and landscape dynamics0 aGrassland ecosystem and landscape dynamics bOxford University Press a128 -1561 aCollins, Scott., L.1 aGlenn, S.M.1 aJoern, Anthony1 aKeeler, K.K. uhttp://knz.lternet.edu/content/grassland-ecosystem-and-landscape-dynamics00412nas a2200145 4500008004100000245002500041210002500066260003600091300001100127100001900138700001700157700001900174700001700193856005600210 1995 eng d00aPopulation Processes0 aPopulation Processes aOxfordbOxford University Press a82 -991 aHartnett, D.C.1 aKeeler, K.H.1 aJoern, Anthony1 aKeeler, K.K. uhttp://knz.lternet.edu/content/population-processes00496nas a2200133 4500008004100000245006700041210006700108260002800175300001300203100001900216700001900235700001700254856009100271 1995 eng d00aSoil systems and nutrient cycles of the North American Prairie0 aSoil systems and nutrient cycles of the North American Prairie bOxford University Press a157 -1741 aSeastedt, T.R.1 aJoern, Anthony1 aKeeler, K.K. uhttp://knz.lternet.edu/content/soil-systems-and-nutrient-cycles-north-american-prairie