The influence of the physical, chemical, and microbiological characteristics of decomposing leaves on the growth of the detritivore <i>Tipula abdominalis</i> (Diptera: Tipulidae)

Abstract

This study investigated the effects of changes in the physical, chemical, and microbiological characteristics of decomposing pignut hickory (Carya glabra) leaves on the consumption rate, assimilation efficiency, and growth rate of the detritivore Tipula abdominalis. Larval growth was highest on leaves that had undergone decomposition for intermediate time periods. During this period maximum concentrations in leaf nitrogen, microbial biomass (ATP), and changes in microbial community structure associated with the decomposing leaves were observed. Laboratory feeding studies that investigated the role of these factors on larval growth established that microbial biomass, estimated by 15 N enrichment, and leaf nitrogen concentration did not influence larval growth. However, microbial community structure had a significant influence on T. abdominalis consumption rate, assimilation efficiency, and growth rate. Results suggest that for normal growth T. abdominalis requires a microbial community composed of at least fungi and bacteria within its diet, but for reasons other than as a direct source of carbon and nitrogen.