@article {KNZ001166, title = {Coexisting generalist herbivores occupy unique nutritional feeding niches}, journal = {Proceedings of the National Academy of Sciences}, volume = {105}, year = {2008}, pages = {1977 -1982}, abstract = {

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.

}, keywords = {LTER-KNZ, Biodiversity, Competition, geometric framework, physiological ecology, resource partitioning}, doi = {10.1073/pnas.0711870105}, url = {https://www.pnas.org/content/105/6/1977}, author = {Behmer, S.T. and Anthony Joern} } @article {KNZ00724, title = {Feeding ecology and emergence production of annual cicadas (Homoptera: Cicadidae) in tallgrass prairie}, journal = {Oecologia}, volume = {123}, year = {2000}, pages = {535 -542}, abstract = {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{\textendash}1 year{\textendash}1 in both grassland habitats, and 1.01 kg N ha{\textendash}1 year{\textendash}1 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 δ13C and δ15N signatures indicative of feeding on shallowly rooted C4 plants such as the warm-season grasses dominant in tallgrass prairie ecosystems, whereas T. dorsata signatures suggested preferential feeding on more deeply rooted C3 plants.}, keywords = {LTER-KNZ, grassland, Insect emergence, Nutrient flux, resource partitioning, Stable isotopes}, doi = {10.1007/s004420000335}, author = {Callaham, M.A. Jr. and M.R. Whiles and Meyer, C.K. and B. Brock and Charlton, R.E.} }