Contraction of the life cycle and the Evolution and Diversification of cave beetles

全变性昆虫占动物界物种的50%以上。它们主要有鞘翅目、膜翅目、双翅目和鳞翅目。全异形昆虫的特点是有一个特殊的生命周期，包括一个在生态和形态上与成虫完全不同的幼虫。全变态昆虫也有蛹，因此完全变态。这种完全的蜕变被认为是这个群体在进化上取得无与伦比的成功的主要原因。因此，幼虫阶段的存在可以说是推动谱系多样化的进化关键创新。然而，在少数极端情况下，这种策略似乎不是最优的，并且出现了替代策略，例如在一些殖民地下环境的世系中。有些物种的幼虫寿命非常短，孵化出来的不进食的幼虫会立即化蛹。在此，我们建议利用高度多样化的地面甲虫（甲甲科：蠓科）和一个全面的分子系统发育框架来研究地下环境中幼虫周期收缩与进化成功之间的联系。我们的主要研究问题是：收缩的生命周期发生在哪里？生命周期缩短的进化支是否比正常幼虫发育的进化支更具多样性？因此，强烈衍生的个体发生是否代表了地下甲虫某些进化支多样化的发射台或关键创新？

Holometabolous insects represent more than 50% of the species in the animal kingdom. Their four main orders are Coleoptera, Hymenoptera, Diptera and Lepidoptera. Holometabolous insects are characterized by a peculiar life cycle including a larva radically differing from the adult in terms of ecology and morphoplogy. Holometabolous insects also have a pupa, thus complete metamorphosis. The complete metamorphosis is supposedly the main reason of the unequalled evolutionary success of the group. Presence of larval stages is then arguably an evolutionary key innovation fuelling lineage diversification. However, in few extreme cases, this strategy does not seem to be optimal and alternative strategies emerged, for example in some lineages that colonize the subterranean environment. There are some species where larval life is so strongly abbreviated that the hatched, non-feeding larva pupates immediately.Here we suggest to use highly diverse ground beetles (Carabidae: Trechini) and a comprehensive molecular phylogenetic framework to study the links between contraction of larval cycle and evolutionary success in hypogean environments. Our main research questions are: Where does a contracted life cycle occur? Are clades with contracted life cycle significantly more diverse than clades with normal larval development and does a strongly derived ontogeny therefore represent a launching pad or key innovation for diversification in certain clades of underground beetles?