Paper wasps (genus Polistes) are one of the most species-rich genera of social insect. Prior studies have found that male coloration, male colour pattern, territory choice and female caste are potential drivers of intraspecific mate choice in paper wasps. However, there has been no formal assessment of interspecific mate choice in this group; therefore, the mechanism driving diversification in paper wasps remains an open question. In this study, we measured interspecific and intraspecific mating behaviour between two closely related species of paper wasps, Polistes fuscatus and Polistes metricus. These two species have ample opportunity to interbreed because P. fuscatus and P. metricus forage, nest and mate in the same habitats. We tested the strength of reproductive isolation between these species using no-choice and choice mating trials. Our results show strong, symmetric, prezygotic isolation between P. fuscatus and P. metricus. Males discriminated between conspecifics and heterospecifics but attempted to mate with females of the other species in ~10% of heterospecific mating trials. Female wasps were more discriminating than males and probably evaluated species identity and male quality through visual or olfactory cues. We additionally report sexual dimorphism in P. metricus body size.

中文翻译：

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两个紧密相关的黄蜂物种之间的强烈但不完整的伴侣选择歧视。

黄蜂（Polistes属）是社交昆虫中物种最多的属之一。先前的研究发现，雄性着色，雄性颜色模式，区域选择和雌性等级是黄蜂种内配偶选择的潜在驱动力。然而，该组还没有对种间配偶选择的正式评估。因此，驱动黄蜂多样化的机制仍然是一个悬而未决的问题。在这项研究中，我们测量了两个紧密相关的黄蜂物种Pouses fuscatus和Polistes metricus之间的种间和种内交配行为。这两个物种具有充分的杂交机会，因为褐红假单胞菌和度量标准的P. metricus在同一生境中觅食，筑巢和交配。我们使用无选择和选择交配试验测试了这些物种之间生殖隔离的强度。我们的结果表明，在强力对虾和度量对虾之间存在强的，对称的，合子前分离作用。雄性区分同种和异种，但在约10％的异种交配试验中试图与其他物种的雌性交配。女性黄蜂比男性更具区分性，并可能通过视觉或嗅觉提示评估物种身份和男性质量。我们还报告了度尺体型中的性二态性。