捕食风险会影响行为,生殖投资,and,最终,个人健身。在高风险环境中,雌性经常减少生殖分配,会影响后代表型和繁殖成功。在合作育种者中,帮助者有助于喂养后代,和群体经常一起生活和觅食。助手可以,因此,提高生殖成功率,但也会影响育种者的状况,压力水平和捕食风险。然而,辅助存在是否可以缓冲捕食风险对母体生殖分配的影响仍未研究。这里,我们使用合作繁殖的社交编织者Philetairussocius来测试捕食风险和繁殖群体规模对母体分配到离合器大小的交互影响,鸡蛋质量,蛋黄质量,和蛋黄皮质酮.我们使用成虫主要捕食者的回放增加了产卵前的感知捕食风险,gabargoshawk(Micronisusgabar)。我们还测试了群体规模和产前捕食者回放对后代孵化和雏鸟概率的交互影响。暴露于捕食者的雌性产卵,蛋黄轻4%,但是捕食者的暴露并没有明显影响离合器的大小,鸡蛋质量,或鸡蛋皮质酮水平。回放处理对蛋黄质量的影响与组大小无关,这表明助手的存在并不能减轻捕食风险对产妇分配的影响。尽管捕食者诱导的蛋黄质量减少可能会降低后代的养分利用率,可能会影响他们的生存,回放处理对孵化和成卵成功的影响不明显。助手的存在与捕食者对母体生殖投资的影响之间的相互作用仍然是生活史和生理进化权衡中被忽视的领域,需要进一步研究。
Predation risk can influence behavior, reproductive investment, and, ultimately, individuals\' fitness. In high-risk environments, females often reduce allocation to reproduction, which can affect offspring phenotype and breeding success. In cooperative breeders, helpers contribute to feed the offspring, and groups often live and forage together. Helpers can, therefore, improve reproductive success, but also influence breeders\' condition, stress levels and predation risk. Yet, whether helper presence can buffer the effects of predation risk on maternal reproductive allocation remains unstudied. Here, we used the cooperatively breeding sociable weaver Philetairus socius to test the interactive effects of predation risk and breeding group size on maternal allocation to clutch size, egg mass, yolk mass, and yolk corticosterone. We increased perceived predation risk before egg laying using playbacks of the adults\' main predator, gabar goshawk (Micronisus gabar). We also tested the interactive effects of group size and prenatal predator playbacks on offspring hatching and fledging probability. Predator-exposed females laid eggs with 4% lighter yolks, but predator-calls\' exposure did not clearly affect clutch size, egg mass, or egg corticosterone levels. Playback-treatment effects on yolk mass were independent of group size, suggesting that helpers\' presence did not mitigate predation risk effects on maternal allocation. Although predator-induced reductions in yolk mass may decrease nutrient availability to offspring, potentially affecting their survival, playback-treatment effects on hatching and fledging success were not evident. The interplay between helper presence and predator effects on maternal reproductive investment is still an overlooked area of life history and physiological evolutionary trade-offs that requires further studies.