With the aid of scanning electron microscopy, the external morphology and distribution of the antennal sensilla were described for females of Gryon gallardoi (Bréthes), an egg-parasitoid of coreids. The geniculated and clavated antennae are composed of 12 antennomeres. Along the flagelum we registered dorsal glands and seven types of sensilla: papillary, chaetica of two sizes - long and short types, styloconic grooved-peg, sickle-shaped and trichodea with numerical and spatial variation among the flagellomeres. Functional aspects of the sensilla are discussed in the context of G. gallardoi antennal drumming behavior. Thus, the determination and the description pattern of antennal sensilla in G. gallardoi, in the present study, is an advance regarding the elucidation of the mechanisms involved in the host selection behavior of this species.
Ultrastructure; host selection; egg parasitoid
