Tamanho da larva hospedeira como fator determinante do parasistismo de Diachamimorpha longicaudata em Ceratitis capitata

Abstract

We evaluated the influence of the size of Ceratitis capitata larvae on the choice of Diachasmimorpha longicaudata female by the host larva at the time of parasitism. The parasitoid females and the host larvae were obtained from rearing kept in the Biological Control Laboratory of UNIMONTES. The experimental design was completely at random, with twenty-five replications. The treatments consisted of the use of four different sizes of larvae (larvae at five, six, seven, and eight days old). In each cage were placed two parasitoid females. The larvae parasitoid females were exposed for two hours in "parasitism units." The number of scars on pupae were recorded. The pupae were classified as unparasitized (no scars), parasitized (presence of scar 1) and superparasitized (presence of more than one scar). After emergence, adults were sexed and quantified. We evaluated the preference behavior, the parasitoid's ability to identify the different sizes of the larvae, the effect of host size on parasitism intensity and production of progeny. Females preferred larvae at seven days for oviposition. The females are able to discriminate host larva, so that they laid their unfertilized eggs in smaller larvae, emerging in that case, male, and fertilized eggs in bigger larvae, emerging females. We found an increase in parasitism intensity (superparasitism) in bigger larvae, however, it did not affect the frequency of male and female progeny. The progeny was influenced only by the size of the host larva. The Biggest larvae provided higher frequency of females and the smallest larvae, higher frequencies of males.