PDF(Pubmed)
Abstract：
Snake venoms are primarily used to subjugate prey, and consequently, their evolution has been shown to be predominantly driven by diet-related selection pressure. Venoms tend to be more lethal to prey than non-prey species (except in cases of toxin resistance), prey-specific toxins have been identified, and preliminary work has demonstrated an association between the diversity of diet classes and that of toxicological activities of whole venom. However, venoms are complex mixtures of many toxins, and it remains unclear how toxin diversity is driven by diet. Prey-specific toxins do not encompass the molecular diversity of venoms, and whole venom effects could be driven by one, few, or all components, so the link between diet and venom diversity remains minimally understood. Here, we collated a database of venom composition and diet records and used a combination of phylogenetic comparative methods and two quantitative diversity indices to investigate whether and how diet diversity relates to the toxin diversity of snake venoms. We reveal that venom diversity is negatively related to diet diversity using Shannon\'s index but positively related using Simpson\'s index. Since Shannon\'s index predominantly considers the number of prey/toxins, whereas Simpson\'s index more strongly reflects evenness, we provide insights into how the diet-venom diversity link is driven. Specifically, species with low diet diversity tend to have venoms dominated by a few abundant (possibly specialised) toxin families, whereas species with diverse diets tend to \'hedge their bets\' by having venoms with a more even composition of different toxin classes.
摘要：
蛇毒主要用来征服猎物,因此，它们的进化已被证明主要由饮食相关的选择压力驱动.毒液对猎物的杀伤力往往比非猎物更高（除非有毒素抗性），已经确定了猎物特异性毒素，初步工作表明，饮食类别的多样性与整个毒液的毒理学活动之间存在关联。然而,毒液是许多毒素的复杂混合物，目前尚不清楚毒素多样性是如何由饮食驱动的。猎物特异性毒素不包括毒液的分子多样性，整个毒液效应可以由一个驱动，几个,或所有组件，因此，饮食和毒液多样性之间的联系仍然是最低限度的理解。这里,我们整理了毒液成分和饮食记录的数据库，并结合了系统发育比较方法和两个定量多样性指数来调查饮食多样性是否以及如何与蛇毒毒素多样性相关。我们发现，使用Shannon指数，毒液多样性与饮食多样性呈负相关，而使用Simpson指数则呈正相关。由于香农指数主要考虑猎物/毒素的数量，而辛普森指数更强烈地反映了均匀度，我们提供有关饮食-毒液多样性联系如何驱动的见解。具体来说,具有低饮食多样性的物种往往具有由一些丰富的（可能是专门的）毒素家族主导的毒液，而具有不同饮食的物种倾向于通过毒液具有更均匀的不同毒素类别组成来“对冲他们的赌注”。
