Intravernal Changes in the Level of Parasitization of the Southern Green Stink Bug (Hemiptera: Pentatomidae), by the Feather-Legged Fly (Diptera: Tachinidae): Host Sex, Mating Status, and Body Size as Correlated Factors

In 1989, the number of eggs of the parasitoid, Trichopoda pennipes (F.), on the cuticle of southern green stink bugs, Nezara viridula (L.), increased throughout the spring for the cohort emerging from overwintering diapause. Initially, the size of N. viridula males was positively correlated with the number of parasitoid eggs and probability of mating. By late spring, mating status was not influenced by size and the relationship between size and number of parasitoid eggs was much reduced. This may reflect a loss of viability for larger, more parasitized males resulting in a concomitant reduction in attractiveness to potential mates and parasitoids. The proportion of males in the cohort dropped significantly and coincidentally with increased levels of parasitization. Throughout the spring, females were parasitized much less than males. The risk of parasitization for females derived primarily from their association with males during courtship and/or copulation.