No room for males in caves: Female‐biased sex ratio in subterranean amphipods of the genus Niphargus
No room for males in caves: Female‐biased sex ratio in subterranean amphipods of the genus Niphargus
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洞穴中没有雄性的空间：Niphargus 属地下片脚类动物性别比例偏向雌性
DOI：
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发表时间：
2021
影响因子：
2.1
通讯作者：
C. Fišer
中科院分区：
文献类型：
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作者：
Ester Premate;Špela Borko;S. Kralj;M. Jennions;Ž. Fišer;G. Balázs;Anna;G. Bračko;D. Copilaș‐Ciocianu;Nuša Hrga;G. Herczeg;Behare Rexhepi;M. Zagmajster;V. Zakšek;L. Fromhage;C. Fišer
性别分配理论预测，女儿与儿子的比例将随着生态条件的变化而变化，而生态条件决定了生产每种性别的成本和收益。在其他条件相同的情况下，成体性别比（ASR）也应随生态条件而变化。许多关于地下物种的研究报告了女性偏向的 ASR，但尚未进行系统研究。我们检验了这样一个假设：随着与地表的隔离增加，ASR 变得更加偏向女性。我们编制了地下片脚类 Niphargus 35 个物种的 ASR 数据集，每个物种都生活在三个不同的栖息地（地表-地下边界、洞穴溪流、潜水湖）之一，代表了地下隔离增加的环境梯度。 35 个物种中，有 27 个物种的 ASR 呈雌性偏向； 12 个物种的偏差具有统计学意义。经过系统发育校正后，我们发现栖息地之间的 ASR 存在显着差异。在地表-地下边界，女性偏向性最弱，在潜水湖中，女性偏向性最强。额外的模型表明，对于地表-地下边界和洞穴溪流栖息的物种，ASR 已经朝着单一值的方向发展，而对于 11 个潜水湖居民中的 9 种来说，ASR 已经朝着单一值的方向发展。我们认为，地下种群的近亲繁殖历史可能会降低近亲繁殖抑制，从而使亲缘选择有利于与兄弟姐妹交配。由于兄弟之间的本地配偶竞争，这可能会选择偏向女性的后代性别比例。观察到的地下物种性别比例模式使它们成为一个值得对性别分配理论感兴趣的人更多关注的群体。
Sex allocation theory predicts that the proportion of daughters to sons will evolve in response to ecological conditions that determine the costs and benefits of producing each sex. All else being equal, the adult sex ratio (ASR) should also vary with ecological conditions. Many studies of subterranean species reported female‐biased ASR, but no systematic study has yet been conducted. We test the hypothesis that the ASR becomes more female‐biased with increased isolation from the surface. We compiled a data set of ASRs of 35 species in the subterranean amphipod Niphargus, each living in one of three distinct habitats (surface‐subterranean boundary, cave streams, phreatic lakes) representing an environmental gradient of increased isolation underground. The ASR was female‐biased in 27 of 35 species; the bias was statistically significant in 12 species. We found a significant difference in the ASR among habitats after correction for phylogeny. It is most weakly female‐biased at the surface‐subterranean boundary and most strongly female‐biased in phreatic lakes. Additional modelling suggests that the ASR has evolved towards a single value for both surface‐subterranean boundary and cave stream‐dwelling species, and another value for 9 of 11 phreatic lake dwellers. We suggest that a history of inbreeding in subterranean populations might lower inbreeding depression such that kin selection favours mating with siblings. This could select for a female‐biased offspring sex ratio due to local mate competition among brothers. The observed patterns in sex ratios in subterranean species make them a group worthy of more attention from those interested in sex allocation theory.