ULTRASTRUCTURE OF THE SPERMATHECA AND ITS ASSOCIATED GLAND IN THE ANTCREMATOGASTER-OPUNTIAE (HYMENOPTERA, FORMICIDAE)

Sperm storage by females has reached an extreme degree of development in ants. Ant queens, which are usually long-lived insects, typically s tore and maintain an unreplenished supply of viable sperm for ten or m ore years. The spermatheca of Crematogaster opuntiae includes a recept acle and a discrete pair of accessory, or spermathecal, glands, struct ures commonly found in sperm storage organs of insects. The beanshaped receptacle consists of a layer of simple epithelium externally and a cuticular layer internally. In the hilar region, the epithelium is hig hly columnar and exhibits ultrastructural features characteristic of t ransport epithelia, such as infolded basal membranes, abundant polymor phic mitochondria, and apical microvilli. The spermathecal glands cont ain cells that have long, dense microvilli that project into a central lumen, abundant mitochondria, and large fields of glycogen. The valve and pump region of the spermatheca provide a mechanism to conserve sp erm by controlling the rate of sperm release. The columnar epithelium may function as excretory tissue that serves to maintain an environmen t in which sperm can remain viable for many years.