Antennae and its sensillum in the female and male Apocrypta sp.were examined by using environmental scanning electron microscope, and then were discussed on the basis of evolutionary adaptation of morphological characteristics.Apocrypta sp.has a typical sex dimorphism on the whole antennae.Antennae of female fig wasps are 862.75±20.65μm in length,and consist of a radicula, scape, pedicel,and flagellum which is composed of 10 flagellomeres.Seven morphological sensillar types were identified in females,including trichoid sensilla,chaetica sensilla (type Ⅰ and Ⅱ),basiconic sensilla (type Ⅰ),multiporous placoid sensilla (non-grooved types), basiconic capitate peg sensilla,and böhm's bristles.Antennae of male fig wasps are substantially reduced,345.18±9.44μm in length,and comprised of a scape, pedicel and flagellum that contains 1 antennomere.Five sensillar types were found in males,including trichoid sensilla,basiconic sensilla (type Ⅱ),multiporous placoid sensilla (grooved types),coeloconic sensilla, and böhm's bristles.The abundance of antennal sensilla of female far exceeded that of males.Significant differences were observed in the sensillar morphology,distribution,or pore density of the same type of antennal sensilla between female and male fig wasps.The pressure-adaptive morphology of the various types of the antennal sensilla demonstrated the positive dependence on the morphological division and ecological adaptation.Due to different ecological functions of females and males, they produced the pressure-adaptive morphologies,which correlated with the oviposition behaviors of females and with the mate choice of males in fig cavity.Our results will facilitate the understanding of the intrinsic relationships between the morphological division,reproductive behavior,and chemical utilization and partition in the sexual selection of fig wasps.