The eggs of European satyrine butterflies (Nymphalidae): external morphology and its use in systematics

Abstract

A comparative study of the external chorion morphology of West-Palaearctic satyrine butterflies is attempted, based on descriptions of 38 species and a survey of previously published data. The correlations between selected characters, the results of phylogenetic analysis based on egg characters, and their congruence with the current taxonomy of these butterflies, are tested, in order to estimate the potential use of egg characters in systematic studies. A relatively high number of characters may be derived from the outer chorion morphology, although decisions on homology may require detailed knowledge of the fine structure of chorion. There is evidence for correlation between some quantitative traits, like egg size and number of micropyles, which might in turn depend on adult size. Egg morphology can sometimes be interpreted in terms of ecological adaptations, and hence provides information that should be used in systematics. Evidence from satyrine butterflies suggests that the external chorionic features are highly homoplasious, and probably more useful at low than at high taxonomic levels within Satyrinae.