Effects of Different Foundress Densities on Sex Ratio of the Offspring of Bethylid Wasps

【Objective】 Sex ratio adjustability is a widespread ecological phenomenon in parasitic wasps. A female-biased sex ratio has long been asserted as the evolutionary stable strategy for some gregarious parasitic wasps on account of the theory of local mate competition（LMC）. This evolutionary stable sex ratio can only be equalized as the increasing of foundresses numbers. The bethylid wasps have been widely used as biocontrol agents for several cerambycid and buprestid larvae, and their sex ratio structures are the basis of biocontrol. This study aims to clarify the sex ratios of the bethylid wasps and to prove whether the LMC model was applicable to the prediction of their sex ratios under different foundress densities. 【Method】 In this study, Sclerodermus guani, S. pupariae, and S. alternatusi were selected as the experimental objects. The changes of offspring sex ratio and the brood size per female of three bethylid wasps were analyzed when the foundress densities ranged from one to eight respectively. The mea