Structure of antennal sensilla in the caddisfly genus Rhyacophila pictet (Trichoptera, Rhyacophilidae)

Abstract

Microstructure and distribution of sensilla were studied in 25 species of caddisflies of the family Rhyacophilidae for the first time. Comparative analysis allowed 13 sensilla types to be identified in members of this family: long grooved trichoid, curved trichoid, chaetoid, mushroom-like pseudoplacoid, forked pseudoplacoid, leaf-like pseudoplacoid, dissected pseudoplacoid, multiforked pseudoplacoid, styloconic, auricillic, coronal, basiconic sensilla, and Böhm’s bristles. The largest variations were found in the pseudoplacoid sensilla. Dissected, leaflike, auricillic, and multiforked sensilla were discovered in the order Trichoptera for the first time. Curved trichoid sensilla can be grouped or assembled into sensory fields. The total number of sensilla per antennal segment decreases towards the antenna apex. Data on the structural diversity of sensilla in groups of fast-evolving species suggest the participation of sensilla structures in the speciation processes.