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Study on social and ecological factors promoting cooperative polyandry in fish and on their reproductive tactics

促进鱼类合作一妻多夫的社会生态因素及其繁殖策略研究

基本信息

批准号：
13640635
负责人：
KOHDA Masanori
金额：
$ 1.92万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640635/
关键词：
Cooperative breeding Cooperative polyandry Female control of paternity Mating systems Sperm competition Cooperation and conflict of interest Reproductive tactics Cichlid fishes 一妻多夫制共同繁殖雌の操作利害の対立繁殖戦略ランプロギーニ種タンガニイカ湖父子判定

项目摘要

Male investment to testes, female control of paternity distribution between territorial males and helper males, and effect of fish body size in cooperatively breeding cichlid fish Julidochromis transcriptus were studied in laboratory conditions during 2001 and 2004.In this cooperatively polyandrous fish, it was cleared that both two males in polyandry invested in testes size significantly much more than males in monogamous situation where sperm competition should not exist. Moreover, the polyandrous males have already increased the testes size after one month of the start of experiment, suggesting they can immediately change the degree of investment This is the first document that individual males can dynamically change testes investment according with the intensity of sperm competition.Female control of paternity distribution was confirmed by using designated artificial nests In this case, results obtained from experimental fish of cooperative breeding (trio) were compared with those … More of paired fish. Female with territorial pair male and small helper males spawned egg masses in wider ranges than paired females. DNA analysis of eggs revealed that 1) eggs of polyandrous females were sired by both males, 2) eggs in inner side of nest were sired by small helper males and those in outside of the masses were sired by large pair males. This tendency suggests that potyandryous female spawned eggs in wider range to fertilize the egg by both males. The manipulation of egg depositing site by females may provide the chance of female control of paternity distribution between the two males. When small males sired more number of eggs, they tended to provide more paternal care. This implies that the female afford to obtain more paternal care through her control of paternity, as has been indicated in cooperative polyandrous bird, the dunnocks. This study will be the first that provide evidence of female control of paternity in fish.Our field studies on the mating system of J.ornateus, the congeneric species to J.trascriptus revealed that the former has a variety of mating systems, monogomay, cooperative polyandry and haremic polygamy. It is suggested that the main ecological factor inducing the variation is wide size variation in both sexes. We tested the hypothesis, using J.trascriptus of 3 males and 3 females in the same experimental aquaria. When size of all fish were similar monogomay was predominant. When one male was much larger than others, polygyny was formed in all cases. When a female was dominantly larger, polyandry was made. These results should support the hypothesis.Chalinochrormis brichardi has cooperative polyandrous mating system, in which female control of shared paternity has been suggested. For the control females should obtain wedge shaped nest where small beta males can seek refuge from dominant alpha males. Our preliminary experiment I on female choice of two nests of wedge-shape nest and wide nest which do not have such refuge indicated that the female choose wedge-shaped nests. The results implies that female control may be the case in C.brichard.Cooperative breedings have been documented in birds and mammals. A number of model of reproductive skew have been proposed for understanding of the breeding systems. Recently, members of our research team have revealed that in fish cooperative breeding with unrelated helpers, 1) helpers (beta males) share the paternity, and 2) helper numbers are restricted, one in C.brichard. These are consistent with the prediction from reproductive skew models. However, mechanism of paternity share between two or more unrelated males has not been cleared in these models. Our experimental studies suggest the importance of female control of paternity, which should be paid much more attention. Less

2001年和2004年在实验室条件下研究了合作繁殖的转录朱丽鱼（Julidochromis transcriptus）的雄性对睾丸的投资、雌性对领域性雄性和辅助性雄性间父性分配的控制以及鱼体大小的影响。结果表明，一妻多夫制中的两个雄性对睾丸大小的投资明显高于一夫一妻制中的雄性，而一夫一妻制中的雄性不应该进行精子竞争。存在.此外，一雄多熟雄性在实验开始后一个月就已经增加了睾丸大小，表明它们可以立即改变投资程度。这是第一份关于个体雄性可以根据精子竞争的强度动态改变睾丸投资的文件。通过使用指定的人工巢，证实了雌性对父权分配的控制。将合作养殖试验鱼的结果与合作养殖试验鱼的结果进行了比较， ...更多信息成对的鱼女性与领土对男性和小帮手男性产卵的卵块在更广泛的范围比配对的女性。卵的DNA分析表明：（1）多雄雌体的卵是由两雄体交配而成的;（2）巢内的卵是由小助雄体交配而成的，巢外的卵是由大助雄体交配而成的。这种趋势表明，多雄雌蜂在更大范围内产卵，使两个雄蜂都能使卵受精。雌虫对产卵部位的操纵可能为雌虫控制两雄虫间的亲子关系提供了机会。当小的雄性产生更多的卵时，它们往往会提供更多的父亲照顾。这意味着雌性通过控制父权来获得更多的父亲照顾，正如在合作的一妻多夫鸟中所表明的那样。本研究首次证明了雌性控制鱼类的父权。通过对与黑腹金鲫（J.trascriptus）同源的饰纹金鲫（J.ornateus）的交配系统的实地研究，发现饰纹金鲫具有多种交配系统，包括单配偶制、合作一妻多夫制和单配偶制。由此认为，引起这种变异的主要生态因素是两性个体大小的广泛变异。我们测试的假设，使用J.trascriptus的3名男性和3名女性在同一实验水族箱。当所有鱼的大小相似时，单卵型占主导地位。当一个男性比其他男性大得多时，在所有情况下都形成了一夫多妻制。当雌性体型占主导地位时，就形成了一妻多夫制。这一结果支持了布氏查氏丽鲷的一雄多雄交配系统的假说，即在这种交配系统中，雌性控制着共同的父权。对于对照组，雌性应该获得楔形的巢，在那里小的β雄性可以从占主导地位的α雄性那里寻求庇护。本研究对无庇护所的楔形巢和宽巢两种巢的雌鸟选择进行了初步试验一，结果表明雌鸟选择楔形巢。这一结果表明，布氏锥蝽可能是由雌性控制的。为了理解育种系统，人们提出了许多生殖偏斜模型。最近，我们的研究小组的成员透露，在鱼类合作繁殖与无关的助手，1）助手（贝塔男性）共享的父亲，和2）助手的数量是有限的，一个在C. brichard。这与生殖偏斜模型的预测是一致的。然而，在这些模型中，两个或多个无关的男性之间的父系份额的机制尚未明确。我们的实验研究表明，女性控制父权的重要性，这应该得到更多的关注。少