Reproductive success and nest-site selection in a cooperative breeder: Effect of experience and a direct benefit of helping
Reproductive success and nest-site selection in a cooperative breeder: Effect of experience and a direct benefit of helping
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作者：
Hatchwell, BJ;Russell, AF;Ross, DJ
在合作繁殖的长尾山雀（Aegithalos caudatus）种群中，我们确定了巢址特征是否影响繁殖成功，以及经验是否影响巢址选择。巢捕食率高；只有17%的繁殖尝试产生了羽翼丰满的幼鸟。巢的高度是成功的一个重要决定因素；低巢明显比高巢更成功。繁殖者的年龄、出生巢址和繁殖经验对巢址选择没有显著影响。然而，失败的繁殖者在帮助同种异种成功筑巢后建造的巢穴比他们帮助之前建造的巢穴要低。没有提供帮助的失败的繁殖者没有显示出后续巢穴高度的降低。此外，提供帮助的失败育种者随后的繁殖成功率显著高于没有提供帮助的失败育种者。我们的结论是，帮助者通过他们的帮助者经验获得了巢穴质量的信息，从而从他们的合作行为中获得了直接的适应性利益。我们认为，作为帮助者的经验提供了比繁殖经验更可靠的巢穴质量线索，因为帮助者只有在筑巢阶段才与巢穴联系在一起，那时很少有巢穴被破坏。相比之下，尽管成功的繁殖者可能会在低巢中获得成功，但他们更有可能经历低巢的失败，因为低巢的捕食率很高。
We determined whether nest-site characteristics influence reproductive success and whether experience influences nest-site selection in a population of cooperatively breeding Long-tailed Tits (Aegithalos caudatus). Nest predation was high; only 17% of breeding attempts resulted in fledged young. The height of nests was an important determinant of success; low nests were significantly more successful than high nests. A breeder's age, natal nest site, and breeding experience had no significant effect on nest-site selection. However, failed breeders who helped at the successful nests of conspecifics built subsequent nests lower than nests built prior to their helping experience. Failed breeders who did not help showed no reduction in the height of subsequent nests. Moreover, the subsequent reproductive success of failed breeders who helped was significantly higher than that of failed breeders who did not help. We conclude that helpers gain information on nest-site quality through their helping experience and thus gain a direct fitness benefit from their cooperative behavior. We suggest that experience as a helper offers a more reliable cue to nest-site quality than breeding experience because helpers are associated with nests only during the nestling phase when few nests are depredated. In contrast, although successful breeders may experience success with a low nest, they are even more likely to have experienced the failure of low nests because of the high rate of nest predation.