Seasonal Production Dynamics in a Guild of Periphyton-Grazing Insects in a Southern Appalachian Stream

Temporal partitioning has been found to be a predominant mode of ecological segregation among groups of systematically related stream insects. We extended this concept to a functionally similar but systematically diverse group of species. The life cycles and secondary production of six species of periphyton-grazing insects (scrapers) were studied in a fourth-order unshaded stream reach in the southern Appalachian Mountains. Total annual production (as ash-free dry mass) calculated with the instantaneous-growth rate method was 1195 mg/m^2. The size-frequency estimates was 6.4% lower. Annual production (AFDM) by species ranged from 612 mg/m^2 for Glossosoma nigrior to 10 mg/m^2 for Goera fuscula. The production peaks of the six species occurred at separate points in the year, with very little overlap between species. Comparison with a neutral model indicated that production peaks were significantly more regularly spaced (P @