MALE ANTENNAL GLAND OF AMITUS-SPINIFERUS (BRETHES) (HYMENOPTERA, PLATYGASTRIDAE), LIKELY INVOLVED IN COURTSHIP BEHAVIOR

The functional anatomy of integumentary adjacent glands of the 4th mal e antennomere, termed male sex-antennomere (MSA4), of Amitus spiniferu s (Brethes) (Hymenoptera: Platygastridae), is described. Externally, t he lateral side of the MSA4 presents an elliptical, glabrous, and elev ated plate with about 20 scattered pores. Internally, there is a gland ular area consisting of some 20 isolated, 2-celled secretory units ben eath the elevated plate. Each gland has a secretory cell, forming a cu ticular receiving canal, and a canal cell, forming the conducting cana l, which connects the receiving canal to the external glandular openin g. The abundant secretion appears on the cuticular surface in cylindri cal forms and as droplets, and probably acts as a recognition and/or a n aphrodisiac pheromone during mating. This hypothesis is discussed wi th regard to behavioral observations reported for only 3 other known c ases of similar glands in parasitoids. Modified antennomeres with spec ialized structures are briefly reviewed, and their secretory function and taxonomic importance in parasitic Hymenoptera, suggested.