Structure, Diversity, and Distribution of Antennal Sensilla in the Caddisfly Superfamily Psychomyioidea (Trichoptera, Annulipalpia)

A comparative morphological study of structure and localization of antennal sensilla in the caddisfly superfamily Psychomyioidea was carried out for the first time. The morphology of antennal sensilla was studied using scanning electron microscopy in 21 species from the families Psychomyiidae (6), Xiphocentronidae (1), Dipseudopsidae (3), Polycentropodidae (9), and Pseudoneureclipsidae (2). Seven types of antennal sensilla were revealed in the studied species: long trichoid, curved trichoid, chaetoid, basiconic, coronary, styloconic, and pseudoplacoid. The distribution of different types of sensilla in the studied families mainly corresponds to the ground plan of the antennal sensory surface in Trichoptera. Long trichoid and pseudoplacoid sensilla usually have nonspecific distribution; chaetoid ones have fixed distribution; basiconic, coronary, and styloconic sensilla have specific distribution. Sensory fields of curved trichoid sensilla are located on the basal antennal segments, always on their ventrolateral surfaces. Three types of shape of sensory fields were revealed in the studied species. The antennal sensory surface is generally conservative in species of the superfamily Psychomyioidea, but particular evolutionary lineages show modifications in the structure and localization of sensilla.