Characterization of Hydropsyche slossonae (Trichoptera: Hydropsychidae) capture net polypeptides

The aim of this study was to characterize polypeptide components of the capture net spun by trichopteran larvae Hydropsyche slossonae (Banks) (Trichoptera: Hydropsychidae). Thirty-one polypeptide bands were identified by SDS - polyacrylamide gel electrophoresis (SDS-PAGE) from extracted net material, with molecular weights ranging from 8500 to 179 000. Comparison with published data on Bombyx mori (L.) (Lepidoptera: Bombycidae) silk, treated under similar denaturing conditions, shows that six low molecular weight polypeptides ranging between 8500 and 18 800 in the silk of H. slossonae are absent from that of B. mori; furthermore, two high molecular weight polypeptides (210 000 and 220 000) detected in the silk of B. mori are not present in that of H. slossonae. Differences between both groups are probably related to their mode of living and to the specific use of silk (in air versus under water). Our findings are consistent with the current trend in the literature that silk spun by aquatic and terrestrial insects, as well as those spun by different species, is apparently made of different biopolymers according to the protein constituents. Hence, the polypeptide characterization of silk, combined with sequence data and (or) antibodies cross-reactivity data, could represent a potential tool for taxonomic classification improvement of aquatic insects. These results could eventually be used to characterize hydropsychid capture net anomalies induced by environmental pollution.