PATTERNS IN MAYFLY (EPHEMEROPTERA) WING LENGTH: ADAPTATION TO DISPERSAL?

Abstract

AbstractUsing regression analysis on data compiled from the literature, I compared relationships (forewing versus body length) of mayfly imagoes, as a measure of dispersal, between suborders (Schistonota and Pannota) and among habitat type (lotic, lentic, and mixed). There were no significant differences in slopes or intercepts of the regression lines between sexes. Forewing length changed less markedly with body size for species within the ancestral Schistonota than the Pannota. Regression lines for lake and river forms intersect at 7.85 mm (wing length) and 7.30 mm (body length). Small (body length < 7.3 mm) lentic mayflies have proportionately longer wings than small riverine forms. Large (body length > 7.3 mm) riverine mayflies have proportionately longer wings than lentic forms. Based on these relationships, small lake-dwelling mayflies and large riverine mayflies are best able to disperse. Mayfly species occurring in mixed (both rivers and lakes) habitats exhibited allometric relationships similar to mayflies restricted to rivers.