Mate-seeking and oviposition behavior of Chyliza vittata (Diptera: Psilidae) infesting the leafless orchid Gastrodia elata

摘要

The psilid fly Chyliza vittata is a leaf miner or stem borer of some orchids in Europe and Japan but few studies on its behavior have been published. Here I describe aspects of the reproductive behavior of the species infesting Gastrodia elata, a leafless orchid. Male mate-seeking behavior occurred on flowering G. elata plants that were attractive to egg-laden females, and indeed copulation was observed. Although two or more males were commonly seen on an orchid stem without interaction, males occasionally reacted aggressively toward other males. Females laid eggs on the flowers, floral buds or bracts as well as into the flowers, using their "ovipositor". Almost all orchids studied eventually produced mature capsules; therefore G. elata seemed to suffer limited damage from infestation by C. vittata. Information regarding a natural enemy and pupation habits is also provided.