Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas.
Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
Mol Ecol. 2018 Dec;27(23):4711-4724. doi: 10.1111/mec.14910. Epub 2018 Dec 10.
Identifying traits that facilitate species introductions and successful invasions of ecosystems represents a key issue in ecology. Following their establishment into new environments, many non-native species exhibit phenotypic plasticity with post-introduction changes in behaviour, morphology or life history traits that allow them to overcome the presumed loss of genetic diversity resulting in inbreeding and reduced adaptive potential. Here, we present a unique strategy in the invasive ant Brachyponera chinensis (Emery), in which inbreeding tolerance is a pre-adapted trait for invasion success, allowing this ant to cope with genetic depletion following a genetic bottleneck. We report for the first time that inbreeding is not a consequence of the founder effect following introduction, but it is due to mating between sister queens and their brothers that pre-exists in native populations which may have helped it circumvent the cost of invasion. We show that a genetic bottleneck does not affect the genetic diversity or the level of heterozygosity within colonies and suggest that generations of sib-mating in native populations may have reduced inbreeding depression through purifying selection of deleterious alleles. This work highlights how a unique life history may pre-adapt some species for biological invasions.
确定有助于物种引入和生态系统成功入侵的特征是生态学中的一个关键问题。许多非本地物种在进入新环境后表现出表型可塑性，其行为、形态或生活史特征发生了变化，使它们能够克服由于近亲繁殖和适应潜力降低而导致的遗传多样性损失。在这里，我们提出了入侵蚂蚁中华小家蚁（Emery）的一个独特策略，其中近亲繁殖耐受性是入侵成功的预先适应特征，使这种蚂蚁能够在遗传瓶颈后应对遗传枯竭。我们首次报告，近亲繁殖不是引入后奠基者效应的结果，而是由于姐妹蚁后与其兄弟之间的交配，这种交配在原生种群中预先存在，这可能有助于它规避入侵的代价。我们表明，遗传瓶颈不会影响群体内的遗传多样性或杂合度水平，并表明在原生种群中几代的同系交配可能通过清除有害等位基因的选择降低了近交衰退。这项工作强调了独特的生活史如何使一些物种预先适应生物入侵。
