Social system and reproduction of helpers in a cooperatively breeding cichlid fish (Julidochromis ornatus) in Lake Tanganyika:: field observations and parentage analyses
Social system and reproduction of helpers in a cooperatively breeding cichlid fish (Julidochromis ornatus) in Lake Tanganyika:: field observations and parentage analyses
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DOI：
10.1007/s00265-005-0934-6
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发表时间：
2005-09-01
影响因子：
2.3
通讯作者：
Kohda, M
中科院分区：
文献类型：
--
作者：
Awata, S;Munehara, H;Kohda, M
有人认为，朱利多罗鱼属的一些鱼类，即在双亲照顾下底物孵化的坦噶尼坎慈鱼，与帮助者合作繁殖。我们研究了野生白纹伊蚊的社会制度，并利用微卫星对其遗传亲缘关系进行了分析。在所研究的种群中，确定了三种社会制度模式：一夫一妻制(61%，72组中的44组)，有帮助者的一对(29%，21)，以及有帮助者的一夫多妻制的后宫(由大的女性或大的男性所有者控制；10%，7)。在合作繁育群体中，每个巢的帮手数量在1到6人之间(中位数1)，并且男性帮手的数量多于女性帮手。在两性中，不同社会地位的个体(后宫主人、繁育者和帮手)的体型有所不同。帮助者和后宫主人无论男女都表现出育儿防御，尽管这种频率很低。分子分析表明：(1)帮助者大多与优势繁殖者无关，(2)许多雌雄帮助者对后代有遗传贡献，(3)雄性帮助者有很高的父本成功率(占幼鸟总数的41%)，(4)在观察到的巢中发现了与群体成员无关的大型幼鸟，这可能是由于繁殖者(或帮助者)的更替和幼鸟的迁入。我们讨论了这些结果对于理解该物种复杂的社会系统的意义，特别是与其他合作繁殖的慈济鱼相比，该物种的低繁殖力倾斜。
It is suggested that some fish of the genus Julidochromis, substrate-brooding Tanganyikan cichlids with biparental care, breed cooperatively with helpers. We studied the social system of J. ornatus in the wild and analysed genetic parentage using microsatellites. Within the studied population three patterns of social system were identified: monogamous pairs (61%, 44 of 72 groups), pairs with helpers (29%, 21), and polygamous harems with helpers (controlled by either a large female or large male owner; 10%, 7). In cooperatively breeding groups, the number of helpers at each nest ranged from 1 to 6 (median 1), and male helpers were more numerous than female helpers. In both sexes, the body size was different among individuals of different social status (harem owner > breeder > helper). Helpers and harem owners of both sexes exhibited brood defence although its frequency was low. The molecular analysis revealed that (1) the helpers were mostly unrelated to dominant breeders, (2) many helpers of both sexes contributed genetically to the next generations, (3) male helpers had high siring success (41 % of young in total), and (4) large young unrelated to group members were detected at 30% of observed nests, which may be due to breeder (or helper) replacements and immigration of young. We discuss the implications of these results for understanding the complex social system of this species, especially the low reproductive skew in comparison with other cooperatively breeding cichlids.