Food habits and ecology of mayflies of the St. Maries River in Idaho

Publication Type:

Journal Article

Authors:

Gilpin, Bobby Rex; Brusven, Merlyn A.

Source:

Melanderia, Washington State Entomological Society, Volume 4, p.19-40 (1970)

Call Number:

A70GIL01IDUS

Keywords:

Caudatella edmundsi, Centroptilum sp., Cinygmula sp., Epeorus grandis, Ephemerella tibialis, Heptagenia solitaria, mayfly, Paraleptophlebia bieornuta, Paraleptophlebia heteronea, Paraleptophlebia memorialis

Abstract:

The food habits and ecology of 12 genera and 31 species of mayflies from the St. Maries River were studied. Nymphs of the St. Maries River were basically herbivorous, feeding largely on detritus, diatoms, and filamentous algae. Food habits for most species varied little from habitat to habitat. Intermediate stage and older age-class nymphs usually had similar feeding habits. The distribution of mayfly nymphs of the St. Maries River was variable. Species such as Cinygmula sp. and Ephemerella tibialis had a wide distribution, adapting to a variety of habitats while Epeorus grandis, Centroptilum sp., and Heptagenia solitaria had limited distributions. We believe conditions of the microhabitats greatly influence mayfly distribution. Different mayflies generally had different environmental requirements. Nymphs such as Paraleptophlebia bieornuta, P. heteronea, and P. memorialis had strong affinities to habitats having considerable detritus, while nymphs of Epeorus grandis and Ephemerella edmundsi frequented more silt and detrital-free habitats. The principal physical factors influencing the distribution of mayflies on the St. Maries River are believed to be bottom type and current speed. Moderately-flowing, lightly-silted cobble riffles supported the largest populations of mayfly nymphs.