Tallgrass prairie (TGP) arthropods are diverse and abundant, yet they remain poorly documented and there is still much to be learned regarding their ecological roles. Fire and grazing interact in complex ways in TGP, resulting in a shifting mosaic of resource quantity and quality for primary consumers. Accordingly, the impacts of arthropod herbivores and detritivores are expected to vary spatially and temporally. Herbivores generally do not control primary production. Rather, groups such as grasshoppers have subtle effects on plant communities, and their most significant impacts are often on forbs, which represent the bulk of plant diversity in TGP. Belowground herbivores and detritivores influence root dynamics and rhizosphere nutrient cycling, and above- and belowground groups interact through plant responses and detrital pathways. Large-bodied taxa, such as cicadas, can also redistribute significant quantities of materials during adult emergences. Predatory arthropods are the least studied in terms of ecological significance, but there is evidence that top-down processes are important in TGP.

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The emergence phenology and feeding ecology of annual cicadas in tallgrass prairie are poorly documented. However, these large insects are abundant, and their annual emergence represents a potentially important flux of energy and nutrients from belowground to aboveground. We conducted a study at Konza Prairie Research Natural Area in eastern Kansas to characterize and quantify cicada emergence and associated energy and nutrient fluxes. We established emergence trap transects in three habitat types (upland prairie, lowland prairie, and riparian forest), and collected cicadas every 3 days from May to September. A subset of trapped cicadas was used for species- and sex-specific mass, nutrient, and stable isotope analyses. Five species were trapped during the study, of which three were dominant. Cicadetta calliope and Tibicen aurifera exhibited significantly higher emergence production in upland prairie than in lowland prairie, and were not captured in forested sites at all. T. dorsata emerged from all three habitat types, and though not significant, showed a trend of greater abundance in lowland grasslands. Two less abundant species, T. pruinosa and T. lyricen, emerged exclusively from forested habitats. Nitrogen fluxes associated with total cicada emergence were estimated to be ∼4 kg N ha year in both grassland habitats, and 1.01 kg N ha year in forested sites. Results of stable isotope analyses showed clear patterns of resource partitioning among dominant cicada species emerging from grassland sites. T. aurifera and C. calliope had δC and δN signatures indicative of feeding on shallowly rooted C plants such as the warm-season grasses dominant in tallgrass prairie ecosystems, whereas T. dorsata signatures suggested preferential feeding on more deeply rooted C plants.

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Six hydrocarbon components (2-methylhexadecane,n-heptadecane, 2-methylheptadecane, 2-methyloctadecane,n-nonadecane, and 2-methylnonadecane) were identified in sex-pheromone gland extracts and in airborne collections ofHolomelina lamae. Low variability in the ratio of components among individuals indicates tight regulation of blend composition. Minor changes were evident in the quantity and ratio of the blend as a function of time of day. Based on gland extracts, the total quantity of the six components increased from day 1 (X = 6299 ng) to day 4 (X = 7498 ng) and subsequently decreased. No significant correlations were found between total gland contents and wet or dry weights of moths. Emission rates ofH. lamae females were determined from pheromone adsorbed onto Porapak Q. Quantities released peaked shortly after the onset of calling and decreased rapidly as calling continued. Peak release rates ranged from 13 to 350 ng/10 min, and from 37 to 835 ng/60 min. Noncalling females did not emit detectable quantities of pheromone. Based on release rates and the rate of pulsation of the abdominal tip, the average amount released per pulse is not constant. The mean ratio of components released (0.78∶7.45∶ 84.80∶2.84∶2.59∶1.53) was not very different from the ratio of components in gland extracts of 2-day-old females (0.70∶4.19∶90.12∶ 1.65∶1.91∶1.42). We propose that the blend is atomized rather than volatilized from the gland, thus retaining nearly the same ratios in the female's effluvium as in her gland.

Pheromone disruptants were tested from 1989 to 1992 in western New York to determine effect on trap catch and potential use in the control of obliqueblmded leafroller. Clwristoneurct rosacearw (Harris), using polyethylene tube tie and controlled-release membrane dispensers in plots of 0.2-2.4 ha. Effectiveness of pheromone at different application rates and canopy locations was evaluated using synthetic pheromone-baited traps, molassesbaited traps, and by inspecting foliar terminals and fruit for leafroller damage. All pheromone treatments significantly reduced (by 56-97%) pheromone trap catches of male moths compared with catches in nontreated blocks. One application of a nahlral-blend formulation at 988 dispensers per hectare was better than 494/ha at dismpting trap catch of both Rights that occur during the year. However, mated female motlls were present in the orchard center as frequently as anywhere else in a pheromone-treated block, indicating either immigration from outside sources or resident females that were not prevented from mating by the pheromone. The membrane dispenser emitted the 3-component natural blend at proportions similar to those in wild female moths. Pheromone traps placed in the tops of trees in a pheromonetreated orchard always caught higher numbers of male moths than those in lower-or middlecanopy positions. Pheromonc treatment resulted in fruit damage similar to tlIat of a pheromone + insecticide treatment under low to moderate leah'oller population pressure (i.e., 3-5% fruit damage in untreated orchards); however, no control method was able to reduce damage to acceptable levels in all cases.

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