Larval morphology and preliminary ecological observations of the uniquely phytophagous rove beetle Himalusa thailandensis (Coleoptera: Staphylinidae: Aleocharinae)

Abstract

AbstractImmature stages of the uniquely phytophagous staphylinid, Himalusa thailandensis Pace, Klimaszewski, and Center, 2010 (Coleoptera: Staphylinidae: Aleocharinae) are described. Adults chew or scrape leaf surfaces while larvae bore into leaf petioles where they mature, and then drop to the ground to pupate in silken cocoons. Compared to other aleocharines, the larval body form is unusually compact and rotund, and may be an adaptation to living within the confines of plant tissue. Mandible and maxilla morphology is unique among known larval aleocharines in being robust and dentate, and we suggest this is adaptive for scraping and squeezing plant tissue. The larval defensive gland is ribbed and gland sac ducts are kinked and apically bifid. We suggest that H. thailandensis may share this derived gland morphology with Autaliini, Bolitocharina, Gyrophaenina, Homalotina, Leptusina, and Silusina of Homalotini, and possibly Liparocephalini. The morphology and ecology detailed here for H. thailandensis is the first comprehensive description of immature stages among aleocharines where adults feed externally on plants.