Reproductive strategies and parasitization behavior of Ageniaspis citricola, a parasitoid of the citrus leafminer Phyllocnistis citrella

Abstract

We investigated the ability of the encyrtid Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtidae), a polyembryonic endoparasitoid of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), to distinguish unparasitized hosts from those previously parasitized by the same female or by a conspecific. The oviposition behavior of A. citricola was observed, and the sequence and duration of each component recorded. Oviposition behavior by experienced and inexperienced A. citricola females was studied using 2, 10, or 20 P. citrella eggs laid on citrus leaves. Dissections of parasitized hosts were done to confirm that an apparent oviposition resulted in egg deposition and to determine the number of eggs laid per event. Females of A. citricola are able to discriminate between unparasitized hosts, those previously parasitized by themselves, and those parasitized by a conspecific at all host densities. Females that had never oviposited in unparasitized hosts (inexperienced) showed the same ability. The number of eggs laid per oviposition event, the number of pupae produced, and the sex ratio of the adult progeny suggest that, under these experimental conditions, fertilized eggs develop by twinning to produce two females, and unfertilized eggs produce a single male. Mated females allowed a single ovipositional event deposited two eggs, yet nearly always produced two females and one male. Unmated females allowed a single ovipositional event also deposited two eggs, but the adult progeny were always males.