ULTRASTRUCTURE OF THE MESOSOMAL GLAND OF XYLOCOPA-MICANS LEPELETIER (HYMENOPTERA, ANTHOPHORIDAE) ASSOCIATED WITH PHEROMONE RELEASE

The ultrastructure of the mesosomal gland of Xylocopa micans Lepeletie r (Hymenoptera : Anthophoridae) revealed the gland to be an invaginati on of the integumental membrane between the propodeum and metatergum. The gland consists of a series of finger-like pouches that extend near ly the length of the propodeum just beneath the cuticle. The gland cel ls are characteristic of simple epithelial glands having numerous elon gated mitochondria and an extensive smooth endoplasmic reticulum with abundant aggregations of electron-dense material associated with numer ous membranous channels that lead to the apical cell surface. An elect ron-dense material released at the cell's cuticular border accumulates in numerous channels in the cuticle that coalesce and widen near the base of large hollow spines. It is suggested that the electron-dense s ecretion is released at the tips of hollow spines directly into the ai r-filled gland lumen forming an aerosol. Through thoracic movement, th e aerosol is forced by air currents to the outside through a slit betw een the propodeum and metatergum.