Investigation of Poison Gland of Sphex flavipennis Fabrius, 1793 (Hymenoptera: Sphecidae): Morphology and Ultrastructure

Abstract

The structure of poison gland of Sphex flavipennis was investigated by using, scannig electron microscopy and transmission electron microscopy. Poison apparatus consists of poison gland, poison sac, Dufour's gland and poison needle. Poison is produced in a gland consisting of two ramified glandular tubules terminating in a common sac. Each tubule is 6-8 mm in length and approximately 90 ?m in diameter. These tubules are lined with the secretory cells and duct cells. The secretory cells have a well-developed secretory unit which is open to the lumen of tubules. In addition, there are free ribosomes, large secretory vesicle and a few mitochondria in the cells. Apical surface of cells are lined by irregular microvilli. Glandular tubules go into pear-like sac. Apical surface of the cells in the poison sac are lined cuticle. Outer surface of poison sac is surrounded muscle fibril and connective tissue. Lumen side of glandular tubules and poison sac are surrounded with monolayer epithelial cells.