Parental roles and the amount of care in a bi-parental substrate brooding cichlid: The effect of size differences within pairs
Parental roles and the amount of care in a bi-parental substrate brooding cichlid: The effect of size differences within pairs
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DOI：
10.1163/1568539042664623
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发表时间：
2004-09-01
期刊：
影响因子：
1.3
通讯作者：
Kohda, M
中科院分区：
文献类型：
--
作者：
Awata, S;Kohda, M
双亲鱼的父母角色和照顾量被认为是由性别决定的。我们研究了基板育雏慈鲷Julidochromis ornatus（40-90毫米的总长度），父母双方参与照顾鸡蛋和年轻的父母的行为。在研究人群中，约80%的配对女性比她们的伴侣大，而且配对的女性因体型大小而异。雄性花更多的时间与他们的后代在女性最大的对，而相反的是男性最大的对。当体型差异较大时，这些护理量的差异更加明显，而相似尺寸的对分担父母的任务。这些结果表明，父母照顾的量在很大程度上是由独立的性别J. ornatus对内的相对大小的影响。然而，防御行为的频率是没有不同的女性最大和男性最大的对。这表明，亲鱼角色不会随着个体间个体大小差异的变化而完全改变。较大的父母在社会上占主导地位的合作伙伴，无论性别，和对内的攻击行为的观察表明，较大的鱼很可能使合作伙伴执行父母的照顾。高频率的攻击性遭遇中观察到的相似大小的对比不同大小的。较高的成本与频繁的攻击行为，在类似的大小对可能与他们的小育雏大小，并可能是部分负责的大小，交配与性别大小的差异，在这条鱼。
Parental roles and the amount of care in bi-parental fish have been assumed to be determined by sex. We studied the parental behaviour in a substrate brooding cichlid Julidochromis ornatus (40-90 mm in total length) in which both parents participate in care of eggs and young. In the study population, ca 80% of paired females were larger than their partners and pairs mated assortatively for size. Males spent more time with their offspring in female-largest pairs, whereas the opposite was found for male-largest pairs. These differences in the amount of care were more conspicuous when differences in body size were greater, whereas similar sized pairs shared parental tasks. These results suggest that the amount of parental care is largely affected by the relative size within pairs independent of sex in J. ornatus. However, the frequencies of defensive behaviours were not different in both female-largest and male-largest pairs. This indicates that parental roles would not completely change as the change of the body size difference within pairs. The larger parents were socially dominant over the partners regardless of sex, and observations of aggressive behaviours within pairs suggest that the larger fish are likely to make the partners perform parental care. Higher frequencies of aggressive encounters were observed in the similar-sized pairs than in the different-sized ones. Higher costs associated with frequent aggressive behaviours in the similar-sized pairs may be related to their small brood size, and may be partly responsible for the size-assortative mating with sexual size difference in this fish.