Kinship among interacting individuals is often associated with sociality and also with sex ratio effects. Parasitoids in the bethylid genus Goniozus are sub-social, with single foundress females exhibiting post-ovipositional maternal care via short-term aggressive host and brood defence against conspecific females. Due to local mate competition (LMC) and broods normally being produced by a single foundress, sex ratios are female biased. Contests between adult females are, however, not normally fatal and aggression is reduced when competing females are kin, raising the possibility of multi-foundress reproduction on some hosts. Here we screen for further life-history effects of kinship by varying the numbers and relatedness of foundresses confined together with a host resource and also by varying the size of host. We confined groups of 1 to 8 Goniozus nephantidis females together with a host for 5+ days. Multi-foundress groups were either all siblings or all non-siblings. Our chief expectations included that that competition for resources would be more intense among larger foundress groups but diminished by both larger host size and closer foundress relatedness, affecting both foundress mortality and reproductive output. From classical LMC theory, we expected that offspring group sex ratios would be less female biased when there were more foundresses and from extended LMC theory we expected that sex ratios would be more female biased when foundresses were close kin. We found that confinement led to the death of some females (11% overall) but only when host resources were most limiting. Mortality of foundresses was less common when foundresses were siblings. Developmental mortality among offspring was considerably higher in multi-foundress clutches but was unaffected by foundress relatedness. Groups of sibling foundresses collectively produced similar numbers of offspring to non-sibling groups. There was little advantage for individual females to reproduce in multi-foundress groups: single foundresses suppressed even the largest hosts presented and had the highest per capita production of adult offspring. Despite single-foundress reproduction being the norm, G. nephantidis females in multi-foundress groups appear to attune sex allocation according to both foundress number and foundress relatedness: broods produced by sibling foundresses had sex ratios similar to broods produced by single foundresses (ca. 11% males) whereas the sex ratios of broods produced by non-sibling females were approximately 20% higher and broadly increased with foundress number. We conclude that relatedness and host size may combine to reduce selection against communal reproduction on hosts and that, unlike other studied parasitoids, G. nephantidis sex ratios conform to predictions of both classical and extended LMC theory.

中文翻译：

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联合创始人的监禁在自然亚社会寄生蜂中引发了亲缘效应


互动个体之间的亲属关系通常与社会性以及性别比例影响有关。寄生蜂属 Goniozus 中的寄生蜂是亚社会性的，单个母蜂通过短期攻击性寄主和针对同种雌性的育雏防御表现出产卵后的母性护理。由于当地的配偶竞争（LMC）以及通常由单一创始人产生的后代，性别比例偏向女性。然而，成年雌性之间的竞争通常不会致命，当竞争的雌性是近亲时，攻击性就会减少，从而提高了某些宿主上多母繁殖的可能性。在这里，我们通过改变与宿主资源限制在一起的创始人的数量和相关性以及改变宿主的大小来筛选亲属关系的进一步生活史影响。我们将 1 至 8 只雌性 Goniozus nephantidis 与宿主一起限制了 5 天以上。多创始人群体要么都是兄弟姐妹，要么都是非兄弟姐妹。我们的主要预期包括，在较大的创始者群体中，对资源的竞争会更加激烈，但会因宿主规模较大和创始者相关性更密切而减弱，从而影响创始者死亡率和繁殖产量。根据经典的 LMC 理论，我们预计，当创始人数量较多时，后代群体性别比例的女性偏见会更少；而根据扩展的 LMC 理论，我们预计，当创始人是近亲时，性别比例会更倾向于女性。我们发现，监禁导致了一些雌性（总体 11%）的死亡，但仅限于宿主资源最有限的情况下。当创始人是兄弟姐妹时，创始人的死亡率不太常见。 多母巢中后代的发育死亡率要高得多，但不受母巢亲缘关系的影响。兄弟姐妹群体共同产生的后代数量与非兄弟姐妹群体相似。对于个体雌性来说，在多母体群体中繁殖几乎没有什么优势：单一母体甚至抑制了最大的宿主，并且成年后代的人均产量最高。尽管单一创始人繁殖是常态，但多创始人群体中的 G. nephantidis 雌性似乎根据创始人数量和创始人相关性来调整性别分配：同胞创始人所产生的后代的性别比例与单一创始人所产生的后代相似（约 100%）。 11% 的雄性），而由非兄弟姐妹产下的雌性产卵的性别比例大约高出 20%，并且随着母鸡数量的增加而普遍增加。我们得出的结论是，相关性和宿主大小可能结合起来减少对宿主群体繁殖的选择，并且与其他研究的寄生蜂不同，G. nephantidis 性别比例符合经典和扩展 LMC 理论的预测。