The ghost sex-life of the paedogenetic beetle Micromalthus debilis.
The ghost sex-life of the paedogenetic beetle Micromalthus debilis.
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DOI：
10.1038/srep27364
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发表时间：
2016-06-07
影响因子：
4.6
通讯作者：
Braig HR
中科院分区：
文献类型：
--
作者：
Perotti MA;Young DK;Braig HR
遗传和性系统在进化枝内部和进化枝之间可以是动态的。然而，确定负责有性生殖和无性生殖、或循环和非循环生命史之间切换的过程仍然具有挑战性。当动物进化出孤雌生殖时，有关性交配系统的信息就会丢失。在这里，我们报告了一个非凡的案例，我们已经能够在一种甲虫中复活有性成虫，这种甲虫通过孤雌生殖进行繁殖，而不产生成虫。通过热处理，我们能够人工诱导 Micromalthus debilis 成虫，以描述其前子代交配系统。成年个体表现出高度女性偏向的性别比例、异系繁殖行为和性别角色逆转。 Micromalthus 的幼虫感染内共生细菌立克次体和沃尔巴克氏体。成人明显的退化迹象与成人的消失同时发生。我们的数据表明，一种古老的女性性别比例偏差早于成年人的消失，可能与内共生体有关。我们提出了一个从单倍体周期性孤雌生殖生活史到孤雌生殖生命史转变的模型。幼虫发育诱导了蠓、黄蜂和甲虫性别比例偏差的新机制。
Genetic and sexual systems can be evolutionarily dynamic within and among clades. However, identifying the processes responsible for switches between, for instance, sexual and asexual reproduction, or cyclic and non-cyclic life histories remains challenging. When animals evolve parthenogenetic reproduction, information about the sexual mating system becomes lost. Here we report an extraordinary case where we have been able to resurrect sexual adults in a species of beetle that reproduces by parthenogenetic paedogenesis, without the production of adults. Via heat treatment, we were able to artificially induce adult beetles of Micromalthus debilis in order to describe its pre-paedogenetic mating system. Adults showed a highly female biased sex ratio, out-breeding behaviour, and sex-role reversal. Paedogenetic larvae of Micromalthus are infected with the endosymbiotic bacteria Rickettsia and Wolbachia. Clear signs of vestigialization in adults are concurrent with the loss of adults. Our data suggest an ancient female sex ratio bias that predates the loss of adults, perhaps associated with endosymbionts. We propose a model for the transition from a haplodiploid cyclical parthenogenetic life history to parthenogenetic paedogenesis. Paedogenetic development induces a new mechanism of sex ratio bias in midges, wasps and beetles.