Carer provisioning rules in an obligate cooperative breeder: prey type, size and delivery rate
Carer provisioning rules in an obligate cooperative breeder: prey type, size and delivery rate
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DOI：
10.1007/s00265-012-1419-z
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发表时间：
2012-12-01
影响因子：
2.3
通讯作者：
Russell, A. F.
中科院分区：
文献类型：
--
作者：
Browning, L. E.;Young, C. M.;Russell, A. F.
为发育中的后代提供食物对后代有益，但对照顾者来说成本高昂。因此，了解供给模式可以产生关于选择如何塑造（异体）父母照顾策略的重要见解。一般来说，后代的发育将受到供给的三个组成部分（猎物类型、大小和分娩率）的影响。然而，这三个变量很少同时考虑，导致人们认为许多研究的结果具有误导性。此外，很少有研究考察专性合作育种者中育种者和非育种助手的供应策略，其中没有帮助的繁殖通常是不成功的。我们研究了专性合作的栗冠鹛（Pomatostomus ruficeps）的这些供给成分。猎物类型与大小相关，而交付率是护理人员提供的食物总量的最佳预测指标。随着幼崽的老化，饲养员和助手同样改变了所提供的不同猎物的相对比例，并增加了猎物的大小和交付率。繁殖中的雌性比雄性繁殖者和成年帮手贡献的猎物少，并且是唯一在有额外照顾者存在的情况下通过降低供给率来减轻负担的照顾者。虽然我们的研究结果表明，繁殖者和助手遵循大致可比的供应规则，但它们也符合这样的观点，即在强制合作物种中，与独立繁殖可能性较低的助手相比，繁殖雌性从为未来繁殖保存资源中受益更多。
Providing food to developing offspring is beneficial for offspring but costly for carers. Understanding patterns of provisioning thus yields important insights into how selection shapes (allo-) parental care strategies. Broadly, offspring development will be influenced by three components of provisioning (prey type, size and delivery rate). However, all three variables are rarely considered simultaneously, leading to suggestions that the results of many studies are misleading. Additionally, few studies have examined the provisioning strategies of breeders and non-breeding helpers in obligate cooperative breeders, wherein reproduction without help is typically unsuccessful. We investigated these components of provisioning in obligately cooperative chestnut-crowned babblers (Pomatostomus ruficeps). Prey type was associated with size, and delivery rate was the best predictor of the overall amount of food provided by carers. As broods aged, breeders and helpers similarly modified the relative proportion of different prey provided and increased both prey size and delivery rate. Breeding females contributed less prey than male breeders and adult helpers, and were the only carers to load-lighten by reducing their provisioning rates in the presence of additional carers. While our results suggest that breeders and helpers follow broadly comparable provisioning rules, they are also consistent with the idea that, in obligately cooperative species, breeding females benefit more from conserving resources for future reproduction than do helpers which have a low probability of breeding independently.