Behavior, functional morphology, and ecology related to feeding in aquatic insects with particular reference to Stenacron interpunctatum, Rhithrogena pellucida (Ephemeroptera: Heptageniidae), and Ephemerella needhami (Ephemeroptera: Ephemerellidae)

Dave McShaffrey, Purdue University

Abstract

Videomacroscopy, scanning electron microscopy, gut content analysis, and other techniques were used to investigate the diet, feeding behavior, and functional morphology of three species of mayflies: Stenacron interpunctatum, Rhithrogena pellucida (Ephemeroptera: Heptageniidae), and Ephemeraella needhami (Ephemeroptera: Ephemerellidae). Stenacron interpunctatum was found to feed on detritus, which it collected using three distinct stereotypic feeding cycles; a brushing cycle was used to feed on loosely attached detritus, a gathering cycle was used to feed on unattached detritus, and a filtering cycle was used to feed on suspended material. Stenacron interpunctatum was classified as a collector-gatherer. Rhithrogena pellucida used two feeding cycles to ingest a diet consisting mostly of periphyton. One cycle utilized the labial palps to brush up loosely attached material, the other cycle utilized the maxillary palps to scrape up tightly accreted material. Rhithrogena pellucida was classified as a scraper. Ephemerella needhami used two feeding cycles to feed on filaments of Cladophora and associated material. One cycle used the maxillae to remove detritus from the filaments, the other used the mandibles to bite off filaments. Ephemerella needhami was classified as a collector-gatherer. Comparative studies of the mouthpart morphology of all three species at the ultrastructural level revealed morphological differences closely associated with microhabitat and diet. Brief accounts of feeding behavior are listed for gastropods, amphipods, other mayflies including: Callibaetis, Isonychia, Potamanthus, Heptagenia, Stenonema, Ephoron, and Caenidae; the caddisfly Macrostemmum, water pennies, larval blackflies, and the midge Cricotopus. The application of the techniques developed in this study to such diverse organisms proves the utility of these techniques for future studies.

Degree

Ph.D.

Advisors

McCafferty, Purdue University.

Subject Area

Entomology

COinS