Antennal structure of male and female Aphidius rhopalosiphi DeStefani-Peres (Hymenoptera:Braconidae): description and morphological alterations after cold storage or heat exposure

Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure has never been described. We describe here the types and distribution of antennal sensilla in Aphidius rhopalosiphi, a larval parasitoid of several aphid species and observe how this antennal structure is modified after cold storage or heat exposure. Six types of sensilla were found on both male and female antennae. Male and female antennae differed in the total number of antennomeres (16 in males, 14 in females) and in the number and distribution of three of the six types of sensilla. After cold storage or heat exposure, we observed the appearance of a small number of abnormal sensilla.