Comparison of antennal sensilla of Anaphes victus and A-Listronoti (Hymenoptera, Mymaridae), egg parasitoids of Curculionidae

Antennal sensilla were compared in females and males of two sympatric mymar id Hymenoptera, Anaphes victus and A. listranoti which are, respectively, s olitary and gregarious parasitoids of eggs of the carrot weevil Listronotus oregonensis (Coleoptera, Curculionidae). Both species are morphologically very similar in the area where they are sympatric. The external morphology of the sensilla was studied using scanning electron microscopy. Female ante nnae have seven different types of sensilla, morphologically similar in the two species: trichoid sensilla, which are putative mechanosensilla, sensil la chaetica types 1, 3 and 4, which are presumably contact chemosensilla, a nd sensilla chaetica type 2 and basiconic and placoid sensilla, which are p resumed to be olfactory sensilla. The major difference between the two spec ies is the number of sensilla chaetica type 4, of which 6-9 are found on th e antennal club in A. victus, while 10-12 are present in A. listronoti. The antennae of the males of both species are similar in morphology and in the number and distribution of their four types of sensilla, i.e. trichoid sen silla, sensilla chaetica type I and basiconic and placoid sensilla.