Population Energetics and Ecology of the Rock Grasshopper, Trimerotropis Saxatilis

The ecology and bioenergetics of a population of Trimerotropis saxatilis (Acrididae) were examined in field and laboratory studies. This grasshopper species occurs on harsh, desert—like rock outcrops in the southeastern United States and constitutes one of the important consumers in those ecosystems. The rock grasshopper population studied was located on Panola Mountain, ° 16 km southeast of Atlanta, Georgia, USA. Supplemental population data were collected from a nearby granite outcrop, Mt. Arabia. The energy budget equation used was: Production = Ingestion — Egestion — Respiration. Production, ingestion and respiration were measured, and egestion was determined by difference. The energy budget and population ecology parameters for T. saxatilis were compared with those reported for other orthopteran species. The parameters for T. saxatilis were smaller than for any other population studied, reflecting their adaptation to the harsh environment in which they live. Efficiencies, including production/ingestion and assimilation/ingestion, calculted for several orthopteran populations, were found to be relatively constant, indicating that herbivorous orthopterans function similarly in different ecosystems.