Host preference and progeny sex ratio in a solitary koinobiont mealybug endoparasitoid, Anagyrus pseudococci (Girault), in response to its host stage.
Anagyrus pseudococci, a koinobiont endoparasitoid, is a potential biological control agent of Planococcus citri. The effect of host stage of P. citri on the parasitoid preference, development, survival and sex ratio of the offspring was examined. Host susceptibility and preference tests showed that the parasitoid had a significant preference for the older host instars. Percentage parasitization increased 4.8-fold in the adult stage, compared with the second-instar host, although the parasitoid developed and emerged successfully from all stages. Mean developmental time for male parasitoids was faster than for the females. There was some evidence of delayed development of males in young hosts. Higher percentage emergence of parasitoid was observed from older P. citri. A. pseudococci exhibited maternal adjustment of sex ratio as a function of host size with an increased proportion of females with the increasing host size. Females maximized their fitness by adjusting offspring sex ratio in response to host size without evaluating the future host quality.