Parasitoid researchers have generally thought that the body size of the mother parasitoid does not affect the fitness performance of the progeny during the immature stage, as long as the progeny develop in the same environment. We reveal for the first time that this is not true for the parasitoid Echthrodelphax fairchildii (Hymenoptera: Dryinidae), which is parasitic on planthoppers. Large females ensured an increased survival rate for their progeny during the immature stage and a large body size at adult emergence. Maternal body size differentially affected the body sizes and survival rates of male and female progeny. Small females did not produce female progeny, and the survival rate of the female progeny increased more steeply with increasing maternal body size than that of the male progeny. Meanwhile, the body size of male progeny increased more steeply with increasing maternal body size. The influence of maternal body size on progeny survival to adult emergence has never been reported in insects before. In addition, large females were more likely to lay female eggs, suggesting that females control the sex ratio of progeny in response to their own body size.

中文翻译：

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大型母亲的后代在未成熟阶段的成活率很高，成年后的寄生虫体型较大。

寄生虫的研究人员普遍认为，只要子代在相同的环境中发育，母性寄生虫的体型就不会影响子代在未成熟阶段的适应能力。我们首次揭示了这种现象对于寄生性Echthrodelphax fairchildii是不正确的（膜翅目：Dryinidae），在飞虱上寄生。大型雌性确保了在未成熟阶段后代的存活率提高，成年后的体型也很大。产妇的体型差异影响男性和女性后代的体型和存活率。小雌性不产生雌性后代，并且随着母体尺寸的增加，雌性后代的存活率比雄性后代增长得更快。同时，雄性后代的体型随着孕产妇体型的增加而急剧增加。以前从未在昆虫中报道过母体大小对子代存活至成年的影响。此外，雌性较大的雌性更容易产卵，这表明雌性根据自身的体型控制后代的性别比例。