00648nas a2200217 4500008004100000245003900041210003900080260003800119300001300157653002200170100001800192700001800210700001400228700002000242700001600262700002000278700001900298700001900317700002400336856007000360 1998 eng d00aAnimal populations and communities0 aAnimal populations and communities aNew YorkbOxford University Press a113 -13910atallgrass prairie1 aKaufman, D.W.1 aKaufman, G.A.1 aFay, P.A.1 aZimmerman, J.L.1 aEvans, E.W.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L. uhttp://knz.lternet.edu/content/animal-populations-and-communities00543nas a2200145 4500008004100000245006900041210006500110260004500175300001300220100001600233700001900249700001800268700001800286856009300304 1995 eng d00aThe relations of phytophagous invertebrates and rangeland plants0 arelations of phytophagous invertebrates and rangeland plants aDenver, CObSociety for Range Management a580 -6341 aEvans, E.W.1 aSeastedt, T.R.1 aBedunah, D.J.1 aSosebee, R.E. uhttp://knz.lternet.edu/content/relations-phytophagous-invertebrates-and-rangeland-plants02390nas a2200133 4500008004100000245009500041210006900136300001500205490000700220520187000227653002202097100001602119856012102135 1992 eng d00aAbsence of interspecific competition among tallgrass prairie grasshoppers during a drought0 aAbsence of interspecific competition among tallgrass prairie gra a1038 -10440 v733 aThe grasshoppers Phoetaliotes nebrascensis and Orphulella speciosa overlap extensively in both diet and habitat in native tallgrass prairie at Konza Prairie, Kansas. I tested for interspecific competition between these two species during a drought year when primary productivity in the prairie was unusually low. In late June 1989, I transferred young nymphs of P. nebrascensis among enclosed plots (each 550—900 m2) to produce three pairs of plots with grasshoppers removed or added. Pretransfer densities in the six plots were estimated at 6 nymphs/m2. Experimental transfers resulted in densities of P. nebrascensis in addition plots 2—3 times as large as in paired removal plots; significant differences in density between addition and removal plots persisted throughout the summer. Densities of O. speciosa in plots with P. nebrascensis removed or added did not differ significantly throughout the growing season of 1989, nor in early summer of 1990. Furthermore, growth and development of O. speciosa in these plots (as measured by rate of maturation, and adult femur length and mass in 1989) were not reduced in the presence of high densities of P. nebrascensis, nor was reproductive potential (measured as the ratio of young nymphs present in early summer 1990 to adults in late summer 1989). These results are similar to those of a previous experiment at the same site during 1987 when primary productivity was moderate. Even under the extreme conditions of 1989, with particularly high ratios of grasshoppers to available food resources, variation in P. nebrascensis density did not adversely affect populations of O. speciosa. These results contrast with recent results for sedentary phytophagous insects, but are consistent with the hypothesis that free—ranging insect herbivores may rarely experience interspecific competition for food resources.10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/absence-interspecific-competition-among-tallgrass-prairie-grasshoppers-during-drought00535nas a2200121 4500008004100000245012400041210006900165300001100234490000800245653002200253100001600275856012200291 1991 eng d00aExperimental manipulation of herbivores in North American native tallgrass prairie: responses of aboveground arthropods0 aExperimental manipulation of herbivores in North American native a37 -460 v12510atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/experimental-manipulation-herbivores-north-american-native-tallgrass-prairie-responses01849nas a2200133 4500008004100000245010000041210006900141300001300210490000700223520133000230653002201560100001601582856011701598 1990 eng d00aDynamics of an aggregation of blister beetles (Coleoptera: Meloidae) attacking a prairie legume0 aDynamics of an aggregation of blister beetles Coleoptera Meloida a616 -6250 v633 a

An aggregation of adults of the ashgray blister beetle, Epicauta fabricii (LeConte), was censused repeatedly for activity on the legume Baptisia australis (L.) in the tallgrass prairie of eastern Kansas. The aggregation persisted for three weeks. Males were more abundant than females throughout the period of aggregation, although females gradually increased in relative abundance over the three-week period. Overall, only 5% of observations were of mating; mating activity was greatest in the early stages of aggregation. The two sexes were similar in the frequency of feeding and in the kinds of plant tissue on which they fed. During the first two weeks of aggregation, the beetles fed primarily on reproductive tissues; in the last week of aggregation, they fed primarily on leaves and stems. The timing of beetle tenure on the host plant was well-suited for consuming the large crop of developing young fruits. Voracious feeding by blister beetles greatly reduced host plant reproductive success; only 20% of the buds, flowers, and fruits present when the aggregation was initiated escaped consumption by the beetles. The seasonal timing of aggregations results in early-opening flowers (and associated fruits and seeds) of the host plant having the greatest chance of escaping destruction by the blister beetles

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/dynamics-aggregation-blister-beetles-coleoptera-meloidae-attacking-prairie-legume01681nas a2200229 4500008004100000245004100041210003700082260004600119300001300165520104300178653000901221100001601230700001601246700001901262700001701281700001601298700001801314700001901332700001601351700002101367856006301388 1989 eng d00aIs fire a disturbance in grasslands?0 afire a disturbance in grasslands aLincoln, NEbUniversity of Nebraska Press a159 -1613 a

Many grasslands, and in particular the tallgrass prairies of North America, are generally thought to be maintained by periodic fire. Semantic disagreement among researchers, however, threatens to hamper discussion of fire as an ecological force in grassland ecosystems. Some authors emphasize that fires are disturbances (or perturbations) since these fires disrupt or alter ecosystem states, trends and dynamics (e.g., accumulating nitrogen is volatilized, plant and animal communities change in composition). Other researchers point out that, because these fire-induced disruptions and alterations can maintain the status quo of the ecosystem (e.g., prevent it from becoming woodland), it is the lack of fire rather than fire itself that should be considered a disturbance. We argue that, since both points of view are useful, there is little to be gained by labeling loosely either fire or lack thereof as a "disturbance" in grassland ecosystems. Key Words: disturbance, fire, grasslands, perturbation, prairie, Kansas

10afire1 aEvans, E.W.1 aFinck, E.J.1 aBriggs, J., M.1 aGibson, D.J.1 aJames, S.W.1 aKaufman, D.W.1 aSeastedt, T.R.1 aBragg, T.B.1 aStubbendieck, J. uhttp://knz.lternet.edu/content/fire-disturbance-grasslands02428nas a2200133 4500008004100000245010100041210006900142300001300211490000700224520190000231653002202131100001602153856012502169 1989 eng d00aInterspecific interactions among phytophagous insects of tallgrass prairie: an experimental test0 aInterspecific interactions among phytophagous insects of tallgra a435 -4440 v703 a

Densities of the grasshopper Phoetaliotes nebrascensis (Acrididae) were manipulated in native tallgrass prairie at Konza Prairie, Kansas, to measure competitive and facilitative effects on densities of co-occurring phytophagous insects. In late June 1987, P. nebrascensis nymphs were transferred among enclosed plots (each 550-900 m2) to produce three pairs of plots with grasshoppers either removed or added. Pretransfer densities in the six plots were estimated at approximately 5 nymphs/m2, 2-2.5 nymphs/m2 were then removed or added. Densities of the manipulated species and other abundant phytophagous insects were subsequently monitored (by sweep net) through mid-August. The manipulations in late June resulted in mean densities of P. nebrascensis nymphs 1.5-4 times as large on addition plots as on removal plots; these differences persisted through mid-August. No significant differences between treatments were found, however, in the numbers of individuals of other Acrididae or Tettigoniidae on four post-transfer sampling dates (July to mid-August). Significant differences were also not found in the numbers of individuals of Phasmatidae, Homoptera, or phytophagous Hemiptera and Coleoooptera, or in the biomasses of live grass, dead grass, or forbs present in mid-August. 1987 was a year of moderate primary production on Konza Prairie. The manipulations produced experimental treatments that mimicked intermediate vs relatively high natural densities of P. nebrascensis. The results indicate that under these conditions, changes in P. nebrascensis density have little net short-term impact, competitive or otherwise, on the population dynamics of co-occurring grasshoppers or other phytophagous insects. Key words: Acrididae, competition, facilitation, grasshoppers, grassland, herbivory, interspecific interactions, phytophagy, Phoetaliotes nebrascensis, tallgrass prairie

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/interspecific-interactions-among-phytophagous-insects-tallgrass-prairie-experimental-test02544nas a2200157 4500008004100000245010400041210006900145300001300214490000700227520195700234653002202191100001602213700001602229700001802245856012302263 1989 eng d00aTiming of reproduction in a prairie legume: seasonal impacts of insects consuming flowers and seeds0 aTiming of reproduction in a prairie legume seasonal impacts of i a220 -2300 v783 a

Seasonal patterns of insect damage to reproductive tissue of the legume Baptisia australis were studies for three years in native tallgrass prairie. Contrasting seasonal patters of damage were associated with the major species of insect consumers. The moth Grapholitha tristegana (Olethreutidae) and the weevil Tychius sordidus (Curculionidae), which together infested 80-100% of developing fruits (pods), consistently damaged more seeds on average in early than in late maturing pods. But while late opening flowers were less subject to attack from moths and weevils, they were more subject to attack from chewing insects, particularly blister beetles (Epicauta fabricii, Meloidae), which destroyed more than 80% of all flowers and developing young pods (including moth and weevil larval inhabitants). The blister beetle arrived late in the flowering season and fed particularly on young reproductive tissue, allowing larger, older pods that had developed from early opening flowers to escape destruction. The relative abundances and impacts of blister beetles, moths, and weevils varied from year to year. Adding to the uncertainty of reproductive success of the host plant were the large and variable amounts of damage to immature buds inflicted by insects (including the blister beetles and weevil adults) and late killing frosts. Thus, timing of flowering is critical to success in seed production for B. australis. The heavy impacts of insects and weather can result in a very narrow window in time (which shifts from year to year) during which B. australis can flower with any success. The opposing pressures exerted by insects and weather on floral reproductive success may act in concert with other features in the plant's biology to foster the maintenance of considerable diversity in flowering times among individuals in local populations of B. australis. Key words: flowering time, grassland, herbivory, phenology, seed predation

10atallgrass prairie1 aEvans, E.W.1 aSmith, C.C.1 aGendron, R.P. uhttp://knz.lternet.edu/content/timing-reproduction-prairie-legume-seasonal-impacts-insects-consuming-flowers-and-seeds01840nas a2200133 4500008004100000245012500041210006900166300001300235490000700248520128600255653002201541100001601563856012701579 1988 eng d00aCommunity dynamics of prairie grasshoppers subjected to periodic fire: predictable trajectories or random walks in time?0 aCommunity dynamics of prairie grasshoppers subjected to periodic a283 -2920 v523 a

Grasshopper communities were sampled by sweep net at six sites in native tallgrass prairie at Konza Prairie, Kansas, USA, in 1982-86 to assess community change from year to year in prairie burned once every four years. Species richness, diversity, and composition of grasshoppers did not vary in regular fashion with the four-year fire cycle. Furthermore, the ratio of grass- to forb-feeding grasshoppers generally did not change consistently during the fire cycle at individual sites, although for all sites combined, the relative abundance of grass feeders initially increased after a fire and subsequently declined in succeeding years without fire. Observed year to year changes in grasshopper communities were tested against those predicted by a random walk model of community change using ordination (DCA) results for species composition at individual sites in individual years. This analysis revealed that local communities varied in restricted, compensatory fashion such that they tended to return towards some central or characteristic species composition when displaced. Thus while fire itself imparts relatively little predictability to grasshopper community dynamics in periodically unburned prairie, such dynamics are nevertheless to a limited degree predictable

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/community-dynamics-prairie-grasshoppers-subjected-periodic-fire-predictable-trajectories-or01832nas a2200133 4500008004100000245013900041210006900180300001500249490000700264520126800271653002201539100001601561856012101577 1988 eng d00aGrasshopper (Insecta: Orthoptera: Acrididae) assemblages of tallgrass prairie: influence of fire frequency, topography, and vegetation0 aGrasshopper Insecta Orthoptera Acrididae assemblages of tallgras a1495 -15010 v663 a

Grasshopper assemblages were sampled by sweep net in native tallgrass prairie at Konza Prairie, Kansas, in 1982-1986 to assess the influences of fire, topography, and vegetation on local species composition. Species composition at 38 sites was analyzed by ordination (detrended correspondence analysis). Frequency of fire and topographic location were reflected along the first two principal axes, respectively. Grass-feeding grasshoppers were more numerous than forb- and mixed-feeding grasshoppers throughout the prairie, but forb and mixed feeders became relatively more frequent as fire frequency decreased. Local species richness of grasshoppers was greater on sites burned infrequently than on sites burned annually or biennially, and on upland than on lowland sites. Local species richness was positively correlated with local plant species richness and diversity, reflecting in part that local relative abundance of forb-feeding grasshoppers was positively correlated with local relative abundance of forbs. Collectively these results are consistent in suggesting that through their effects on local plant communities, fire frequency and topography are major factors influencing the composition of local grasshopper assemblages in tallgrass prairie

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/grasshopper-insecta-orthoptera-acrididae-assemblages-tallgrass-prairie-influence-fire01587nas a2200133 4500008004100000245013400041210006900175300001300244490000700257520102700264653002201291100001601313856012401329 1987 eng d00aDispersal of Lygaeus kalmii (Hemiptera: Lygaeidae ) among prairie milkweeds: population turnover as influenced by multiple mating0 aDispersal of Lygaeus kalmii Hemiptera Lygaeidae among prairie mi a109 -1170 v603 a

Local dispersal and mating behavior of individually marked adult milkweed bugs (Lygaeus kalmii) were studied in a host patch of the milkweed Asclepias viridis in the tallgrass prairie of eastern Kansas. Over a four week period in July, immigration of bugs into the patch was roughly matched by mortality and/or emigration from the patch. Individual males and females visited similar numbers of plants in passing through the host patch, but females spent less time on each plant and dispersed through the patch more rapidly [median (maximum) number of days elapsing between first and last observations of individual bugs: females 1 (21), males 4 (20)]. The bugs spent much of their time in the patch mating (males: 28% of observations; females 41%). Individuals of both sexes mated multiply; individuals were observed mating with as many as six different partners. Mating success on an individual host induced males to remain there longer. Dispersal of females, however, apparently was uninfluenced by mating success

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/dispersal-lygaeus-kalmii-hemiptera-lygaeidae-among-prairie-milkweeds-population-turnover01481nas a2200133 4500008004100000245008200041210006900123300001000192490000700202520099800209653002201207100001601229856010201245 1984 eng d00aFire as a natural disturbance to grasshopper assemblages of tallgrass prairie0 aFire as a natural disturbance to grasshopper assemblages of tall a9 -160 v433 a

Effects of spring wildfire on assemblages of grasshopper (Acrididae) nymphs hatching the following summer were studied in native tallgrass prairie in eastern Kansas, USA. Four watersheds (eight sites) of varying fire history were studied; similarities in initial assemblages of early instar nymphs among these watersheds reflected similarities in burning history. Controlled fires were set on three watersheds. Burning affected assemblage structure of grasshoppers hatching several weeks later, causing shifts in local species compositions as nymphs matured. such change apparently resulted because fire adversely affected survivorship of forb but not grass feeding hoppers. Because forb feeders were relatively most common on burned sites that had previously been protected from fire longest (four years), change in grasshopper assemblages after fire was particularly pronounced at these sites. Greatest species diversities occurred on sites subjected to intermediate frequency of fire

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/fire-natural-disturbance-grasshopper-assemblages-tallgrass-prairie01795nas a2200133 4500008004100000245009800041210006900139300001300208490000700221520128400228653002201512100001601534856011101550 1983 eng d00aThe influence of neighboring hosts on colonization of prairie milkweeds by a seed-feeding bug0 ainfluence of neighboring hosts on colonization of prairie milkwe a648 -6530 v643 a

At Konza Prairie, Kansas, milkweeds (Asclepias viridis) were mapped and censused repeatedly to examine the influence of neighboring conspecifics on colonization of individual host plants by adults of the seed bug Lygaeus kalmii. Analysis by multiple regression suggests that the primary determination of abundance of adult bugs on a host plant was the plant's own pod (seed) production; abundance of adult bugs also increased, however, with increasing pod production by adjacent plants. This neighborhood effect was limited to plants immediately adjacent to a host plant; pod density greater than 3 m distant from hosts had little influence on colonization of hosts by bugs. Mark-recapture studies revealed differences in responses of the two sexes of L. kalmii to neighboring pod density, males lingered longer, while females lingered less on individual plants when these plants were surround by many vs fewer pods. Damage from L. kalmii sustained by milkweeds, thus result from a complex interplay of reproductive behaviors of individual host plants, their neighbors, and their seed predators. (Key words: Asclepias viridis, host plant colonization, host plant dispersion, insect mark-recapture, insect/plant association, Lygaeus kalmii, milkweed, tallgrass prairie)

10atallgrass prairie1 aEvans, E.W. uhttp://knz.lternet.edu/content/influence-neighboring-hosts-colonization-prairie-milkweeds-seed-feeding-bug01801nas a2200169 4500008004100000245011900041210006900160300001500229490000700244520116900251653001601420653002201436100001601458700001701474700002001491856012001511 1983 eng d00aSampling grasshoppers (Orhoptera:Acrididae ) on burned and unburned tallgrass prairie: night trapping vs. sweeping0 aSampling grasshoppers OrhopteraAcrididae on burned and unburned  a1449 -14540 v123 a

Two techniques, sweeping with a canvas net and night trapping with a protable trap, were compared as means of sampling Acridid grasshoppers in burned and unburned tallgrass prairie in eastern Kansas. Mark-release experiements revealed that night traps on both burned and unburned sites throughout the summer captured roughly three-fourths of the grasshoppers when the weather was clear and warm; thus, the technique provides good estimates of seasonal change in absolute density. Ability to capture grasshoppers on unburned vs burned prairie differed for sweep sampling (in contrast to night trapping); only 30% to 40% as many grasdshoppers (per grasshopper present) were collected by sweeping on unburned vs. burned sites. Furthermore, grasshoppers were captured more readily by sweeping as they grew older. Therefore, sweeping provided poor estimates of how the relative abundance of grasshoppers 1) changed seasonally at a site, and 2) differed between burned and unburned sites. Sweeping and night trapping provided similar estimates of the relative abundance of individual specieis present at any one place and time on either burned or unburned prairie

10agrasshopper10atallgrass prairie1 aEvans, E.W.1 aRogers, R.A.1 aOpfermann, D.J. uhttp://knz.lternet.edu/content/sampling-grasshoppers-orhopteraacrididae-burned-and-unburned-tallgrass-prairie-night