Functional anatomy of male antennal glands in three species of Encyrtidae (Hymenoptera: Chalcidoidea).

The occurrence of male antennal glands in three hymenopteran parasitoids belonging to the family Encyrtidae (Leptomastix dactylopii, Rhopus meridionalis and Asitus phragmitis) is reported for the first time. The ultrastructure and function of these glands are described in detail. In all three species the glands consist of clustered unicellular secretory units extending underneath the cuticle. Glandular secretions were released externally and spread onto female antennae by specialized 'release and spread sites', appearing as 'scale-like' or 'peg-like' cuticular structures. These antennal glands play an important role during the complex sequences of courtship behaviour, eliciting female acceptance. The possible behavioural and taxonomical implications are discussed.