Antennal Sensilla of Tamarixia radiata (Hymenoptera: Eulophidae), a Parasitoid of Diaphorina citri (Hemiptera: Psyllidae)

Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) is an effective idiobiont ectoparasitoid of the psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vector of the huanglongbing (citrus greening disease) pathogen. We examined the external and functional morphology of the antennal sensilla of adultmale and femaleT. radiatabyusing scanning and transmission electron microscopy, respectively, to gain insights into the behavioral ecology of this parasitoid. The geniculate antennae of male and female T. radiata were composed of a long scapula-shaped scape with a basal radicula, a barrel-shaped pedicel, and a long ßagellum with a basal ring-like annulus. Five morphologically distinct sensilla, including two types of aporous trichoid sensilla (AST-1 and AST-2), one multiporous trichoid sensillum (MST), one multiporous placoid sensillum (MPS), and one aporous basiconiccapitatepeg sensillumwere identiÞedon theantennaeofboth sexes.Theantennal structures of T. radiata were sexually dimorphic. Male antennae consisted of four funicular ßagellomeres and possessed a greater number of olfactoryMST than female antennae, suggesting their possible function in perception of mate-related volatile cues. Female antennae were characterized by three funicular ßagellomeres and a greater number of MPS than male antennae, suggesting their possible function in the perception of host-related volatile cues. The results are discussed in relation to plausible roles of the identiÞed sensilla in mate and host location by this important parasitoid species.