Djernæs, M. 2011. The sternum V glands in Lepidoptera. —Acta Zoologica (Stockholm) 00: 1–16.
I investigated representatives for all lepidopteran families known to possess the sternum V glands (Micropterigidae, Agathiphagidae, Heterobathmiidae, Erio-craniidae and Lophocoronidae) as well as representatives for the two families (Neopseustidae and Nepticulidae) known to posses fenestrae on sternum IV, structures associated with the sternum V glands in Eriocraniidae. I found significant variation in the gland structure. The gland opening is associated with a variety of cuticular modifications, several of which provide enlarged evaporative surfaces for enhanced dispersal of gland products. The gland reservoir was surrounded by musculature in all families except Agathiphagidae and Nepticulidae, providing means of rapid expulsion of gland products. The fenestra in female Eriocraniidae, Neopseustidae and Nepticulidae are perforated. Furthermore, the fenestra in female Neopseustidae and Nepticulidae are associated with what appears to be functional sternum V glands consisting of a reservoir and secretory tissue albeit without a gland duct. I discuss the evolutionary history and functional considerations of the sternum V gland in Lepidoptera.