Demonstration of Sex Pheromones in \u3ci\u3eMolanna Uniophila\u3c/i\u3e (Trichoptera: Molannidae), \u3ci\u3ePlatycentropus Radiatus, Pycnopsyche Indiana, and P. Subfasciata\u3c/i\u3e (Trichoptera: Limnephilidae), With an Assessment of Interspecific Attraction Between Four Sympatric \u3ci\u3ePycnopsyche\u3c/i\u3e Species

Abstract

Evidence for sex pheromones in the caddisflies Molanna uniophila Vorhies, Platycentropus radiatus (Say), Pycnopsyche indiana (Ross), and P. subfasciata (Say) is presented here for the first time based on field studies conducted in southern Michigan. For all species, numbers of males caught in pheromone traps baited with conspecific female extracts were higher than those caught in traps with male extracts, or those without extract. Four sympatric species of Pycnopsyche: P. guttifer (Walker), P. indiana, P. lepida (Hagen), and P. subfasciata exhibited no interspecific pheromonal attraction despite a common mating season and, in the case of P. indiana and P. lepida, very similar genitalic morphology. Our results suggest the importance of pheromones in maintaining reproductive isolation between closely related species. Likewise, pheromone biology can help delineate morphologically cryptic species