Kin-structured cooperatively breeding groups due to limited dispersal in the obligate shell-brooding cichlid Neolamprologus meeli
Kin-structured cooperatively breeding groups due to limited dispersal in the obligate shell-brooding cichlid Neolamprologus meeli
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由于专性贝壳育雏丽鱼科鱼 Neolamprologus meeli 中的有限扩散而形成亲缘结构的合作繁殖群体
DOI：
10.1007/s00265-022-03201-w
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发表时间：
2022
影响因子：
2.3
通讯作者：
S.
中科院分区：
文献类型：
--
作者：
Saeki;T.;Satoh;S.;Frommen;J. G.;Kohda;M. & Awata;S.
昆虫、鱼类、鸟类和哺乳动物中都有合作繁殖系统的记载，其中父母以外的个体协助抚养后代。尽管如此，推动此类复杂系统演化的因素尚未完全了解。在这里，我们报告了坦噶尼喀湖专性贝类慈鲷鱼Neolamprologus meeli合作繁育的新例子。实地观察表明，占主导地位的雄性要么是一夫一妻制，要么是一夫多妻制，每个雄性与一到四个占主导地位的雌性交配。占主导地位的雌性维持着含有一到十个空腹足动物壳的巢穴，用作繁殖基质和庇护所。这些巢穴中最多生活着四名不成熟的下属，无论性别。它们协助领地防御和巢穴维护，其频率与优势种没有什么不同。亲子关系分析显示，大多数下属都是至少一名饲养员的后代，这表明幼年个体会延迟扩散并帮助抚养它们的亲戚。下属与饲养员的相关性随着体型的增大而下降，并且雌性饲养员的相关性显着高于雄性饲养员。这些模式可能是由配对外的亲子关系、帮手的群体间分散或饲养员流动的性别差异造成的。男性助手比女性助手体型更大，八分之六的分散个体是女性，这表明女性偏向分散。因为N.坦噶尼喀湖的慈鲷在系统发育上与其他合作繁殖的慈鲷不同，这些结果有助于更好地理解鱼类的合作繁殖以及一般复杂社会系统的进化。意义陈述坦噶尼喀湖合作繁殖的慈鲷是研究社会复杂性进化的一个很好的模型，因为合作繁殖在一个小的系统发育群体中至少独立进化了5-6次。在这里，我们提供了慈鲷 Neolamprologus meeli 合作育种的新例子。实地观察表明，这些鱼要么是一夫一妻制，要么是一夫多妻制。下属留在饲养员的巢穴中，帮助保卫领地和维护巢穴。由于性腺不成熟，两性的下属不太可能参与生殖。亲缘分析表明，大多数助鸟和幼鸟都是优势繁殖者的后代，这表明米利猪笼草具有亲缘结构的合作繁殖系统。由于 N. meeli 在系统发育上与所有其他合作繁殖的慈鲷不同，这些结果构成了迄今为止未被描述的独立进化事件，导致了高度复杂的社会系统。
Cooperative breeding systems, where individuals other than parents assist in raising offspring, have been documented in insects, fish, birds, and mammals. Still, the factors driving the evolution of such complex systems are not fully understood. Here, we report a new example of cooperative breeding in the obligate shell-brooding cichlid fishNeolamprologus meelifrom Lake Tanganyika. Field observations revealed that dominant males were either monogamous or polygynous, with each mating with one to four dominant females. Dominant females maintain nests containing one to ten empty gastropod shells used as breeding substrates and shelters. Up to four immature subordinates of either sex lived in these nests. They assisted with territory defense and nest maintenance, the frequency of which was not different from that of the dominants. Parentage analyses showed that most subordinates were the offspring of at least one of the breeders, suggesting that juveniles delay dispersal and help in raising their relatives. The relatedness of subordinates to the breeders declined with increasing body size and was significantly higher to female than to male breeders. These patterns could be caused by extra-pair paternity, between-group dispersal of helpers, or sex differences in breeder turnover. Male helpers were larger than female helpers, and six out of eight dispersed individuals were females, suggesting female-biased dispersal. BecauseN. meeliis phylogenetically distinct from other cooperatively breeding cichlids, these results contribute to a better understanding of cooperative breeding in fishes and to understanding of the evolution of complex social systems in general.Significance statementCooperatively breeding cichlid fishes of Lake Tanganyika are an excellent model for studying the evolution of social complexity because cooperative breeding evolved at least 5–6 times independently in a small phylogenetic group. Here, we provide a new example of cooperative breeding in the cichlid Neolamprologus meeli. Field observations revealed that these fish were either monogamous or polygynous. Subordinates remained in the breeders’ nests and helped with territory defense and nest maintenance. Subordinates of both sexes were unlikely to participate in reproduction because of their immature gonads. Parentage analyses showed that most helpers and juveniles were offspring of the dominant breeders, suggesting that N. meeli has a kin-structured cooperative breeding system. As N. meeli is phylogenetically distinct from all other cooperatively breeding cichlids, these results pose a hitherto undescribed independent evolutionary event, leading to a highly complex social system.