Sib-mating avoidance is a pervasive behaviour that is expected to evolve in species subject to inbreeding depression. Although laboratory studies provide elegant demonstrations, small-scaled bioassays minimize the costs of mate finding and choice, and thus may produce spurious findings. We therefore combined laboratory experiments with field observations to examine the existence of inbreeding avoidance using the parasitoid wasp Venturia canescens. In the laboratory, our approach consisted of mate-choice experiments to assess kin discrimination in population cages with competitive interactions. A higher mating probability after sib rejections suggested that females could discriminate their sibs; however, in contrast to previous findings, sib-mating avoidance was not observed. To compare our laboratory results to field data, we captured 241 individuals from two populations. Females laid eggs in the lab, and 226 daughters were obtained. All individuals were genotyped at 18 microsatellite loci, which allowed inference of the genotype of each female's mate and subsequently the relatedness within each mating pair. We found that the observed rate of sib-mating did not differ from the probability that sibs encountered one another at random in the field, which is consistent with an absence of sib-mating avoidance. In addition, we detected a weak but significant male-biased dispersal, which could reduce encounters between sibs. We also found weak fitness costs associated with sib-mating. As such, the sex-biased dispersal that we found is probably sufficient to mitigate these costs. These results imply that kin discrimination has probably evolved for purposes other than mate choice, such as superparasitism avoidance.

中文翻译：

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昆虫和乱伦：自然寄生的黄蜂的同胞交配耐受力。

避免同胞交配是普遍的行为，预计会在遭受近交衰退的物种中发展。尽管实验室研究提供了很好的证明，但小规模的生物测定可最大程度地减少寻找和选择配偶的成本，因此可能会产生虚假的发现。因此，我们将实验室实验与现场观察相结合，以研究使用寄生性黄蜂Venturia canescens进行近交回避的存在。在实验室中，我们的方法包括配对选择实验，以评估具有竞争性相互作用的种群笼中的亲属歧视。同胞被拒绝后较高的交配概率表明，雌性可以区分同胞。然而，与以前的发现相反，未观察到同胞回避。要将我们的实验室结果与现场数据进行比较，我们从两个人口中捕获了241个人。女性在实验室产卵，并获得226个女儿。所有个体均在18个微卫星基因座进行基因分型，从而可以推断出每个雌性伴侣的基因型，并随后推断出每个配对中的亲缘关系。我们发现观察到的同胞交配率与同胞在野外随机相遇的概率没有差异，这与没有同胞回避的现象是一致的。此外，我们检测到了一个弱但明显的男性偏向散布，这可以减少同胞之间的相遇。我们还发现与同胞交配相关的健身成本较弱。因此，我们发现性别偏见的分散可能足以减轻这些成本。