Colonization of new environments can lead to population bottlenecks and rapid phenotypic evolution that could be due to neutral and selective processes. Exotic populations of the bull‐headed dung beetle (Onthophagus taurus) have differentiated in opposite directions from native beetles in male horn‐to‐body size allometry and female fecundity. Here we test for genetic and transcriptional differences among two exotic and one native O. taurus populations after three generations in common garden conditions. We sequenced RNA from 24 individuals for each of the three populations including both sexes, and spanning four developmental stages for the two exotic, differentiated populations. Identifying 270,400 high‐quality single nucleotide polymorphisms, we revealed a strong signal of genetic differentiation between the three populations, and evidence of recent bottlenecks within and an excess of outlier loci between exotic populations. Differences in gene expression between populations were greatest in prepupae and early adult life stages, stages during which differences in male horn development and female fecundity manifest. Finally, genes differentially expressed between exotic populations also had greater genetic differentiation and performed functions related to chitin biosynthesis and nutrient sensing, possibly underlying allometry and fecundity trait divergences. Our results suggest that beyond bottlenecks, recent introductions have led to genetic and transcriptional differences in genes correlated with observed phenotypic differences.

中文翻译：

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牛头蜣螂外来种群之间瓶颈之外的选择信号，Onthophagus taurus

新环境的定植可能导致种群瓶颈和快速表型进化，这可能是由于中性和选择性过程。牛头蜣螂（Onthophagus taurus）的外来种群在雄性角到身体大小的异速生长和雌性繁殖力方面与本地甲虫的分化方向相反。在这里，我们测试了两种外来和一种本地O. taurus之间的遗传和转录差异在普通花园条件下经过三代的种群。我们对包括两性在内的三个群体中的每一个的 24 个个体的 RNA 进行了测序，并且跨越了两个外来的、分化的群体的四个发育阶段。鉴定了 270,400 个高质量的单核苷酸多态性，我们揭示了三个种群之间遗传分化的强烈信号，以及最近在外来种群之间存在瓶颈和异常位点过多的证据。种群间基因表达的差异在预蛹和成年早期阶段最大，在此阶段雄性角发育和雌性生殖力的差异表现出来。最后，外来种群之间差异表达的基因也具有更大的遗传分化，并执行与几丁质生物合成和营养感应相关的功能，可能是异速生长和繁殖力性状差异的基础。我们的结果表明，除了瓶颈之外，最近的引入导致了与观察到的表型差异相关的基因的遗传和转录差异。