The structure and hydration dynamics of trichopteran (Insecta) egg masses

Abstract

Scanning electron microscopy techniques were used to compare the structure of the gelatinous egg masses of five species of caddisflies (Insecta: Trichoptera) and an aquatic snail (Gastropoda: Pulmonata). The structure of the matrix was different in each species and varied in complexity from amorphous to uniformly channeled to channeled with a cortex of larger channels than those found in the medullar area. In the limnephilid caddisfly Nemotaulius hostilis (Hagen) hydration–dehydration altered channel size and density of the matrix in a reversible manner, which is explained in terms of the molecular structure and hydration dynamics of gels. A direct relationship between the presence of a coarsely channeled cortex and desiccation resistance was observed. This study indicated that egg mass structure may provide information of taxonomic, phylogenetic, and ecological significance in the Trichoptera.