Mutual Interference Among Female Anagyrus kamali Moursi (Hymenoptera: Encyrtidae) and its Impact on Fecundity, Progeny Production and Sex Ratio

Abstract

The solitary endoparasitoid Anagyrus kamali Moursi was introduced to the Caribbean to control populations of Hibiscus Mealybug (HMB) Maconellicoccus hirsutus Green. As part of a biological control programme, mass rearing of A. kamali should produce a maximum of good quality female wasps, because only female parasitoids attack the mealybug. In laboratory experiments conducted at 27 +/- 2°C, mutual interference between female parasitoids on the total oviposition, progeny production and sex ratio was assessed at five parasitoid densities: i.e. 1, 2, 5, 10 and 20 female wasps per 50 mealybugs. Oviposition rates of females decreased with increasing female density, without significantly affecting the sex ratio (average across densities of 0.49 +/- 0.322) (male/female). Under mass-rearing conditions, an increase of the female density from 25 to 75 individuals per cage resulted in an increase of the progeny production from 266 +/- 70.1 to 877.5 +/- 393.3 parasitoids. From 75 to 100 females released per cages, the progeny production was not significantly different with 877.5 +/- 393.3 and 965.3 +/- 608.3 parasitoids produced, respectively. Regardless of the female density, progeny sex ratio remained stable at an average of 0.45 +/- 0.095. As a result, the best efficiency of the mass-production system was obtained at a density of 75 females per cage. However, parasitoid production at this density was inferior to singly caged females by about 50%.