CNRS, IPHC UMR 7178, Université de Strasbourg, Strasbourg, France.
Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
Oecologia. 2021 May;196(1):37-51. doi: 10.1007/s00442-021-04917-8. Epub 2021 Apr 16.
Studies on cooperative breeders have addressed the effects of non-breeding 'helpers' on reproduction and parental care, but the consequences for offspring physiology and long-term survival are less understood. Helpers are expected to benefit offspring, but their presence can also lead to decreased pre- or post-natal parental reproductive effort. To examine whether prenatal and postnatal helpers influence offspring condition, we conducted a whole-clutch cross-fostering experiment in sociable weavers (Philetairus socius) that altered the nestlings' social environment (presence/absence of helpers). We tested whether relative telomere length (rTL), an indicator of somatic maintenance, was influenced by prenatal and/or postnatal presence of helpers 9 and 17 days after hatching, and whether rTL predicted long-term survival. Nine days after hatching, we found an overall positive effect of postnatal helpers on rTL: for nestlings with prenatal helpers, a reduction in the number of helpers post-hatch was associated with shorter telomeres, while nestlings swapped from nests without helpers to nests with helpers had a larger rTL. However, when prenatal helpers were present, an increased number of helpers after hatching led to shorter telomeres. Nine-day old chicks with longer rTL tended to be more likely to survive over the 5 years following hatching. However, close to fledging, there was no detectable effect of the experiment on rTL and no link between rTL and survival. This experimental study of a wild cooperative breeder, therefore, presents partial support for the importance of the presence of helpers for offspring rTL and the link between early-life telomere length and long-term survival.
合作繁殖者的研究已经探讨了非繁殖“帮手”对繁殖和亲代养育的影响，但对于后代生理和长期生存的后果了解较少。帮手有望使后代受益，但它们的存在也可能导致亲代在产前或产后繁殖努力的减少。为了研究产前和产后帮手是否会影响后代的状况，我们在社会性织布鸟（Philetairus socius）中进行了整窝交叉寄养实验，改变了雏鸟的社会环境（有无帮手）。我们测试了相对端粒长度（rTL），一种躯体维持的指标，是否受到产前和/或产后帮手的影响，以及 rTL 是否预测长期生存。在孵化后 9 天，我们发现产后帮手对 rTL 有总体的积极影响：对于有产前帮手的雏鸟，孵化后帮手数量的减少与较短的端粒有关，而从没有帮手的巢穴转移到有帮手的巢穴的雏鸟具有更大的 rTL。然而，当产前帮手存在时，孵化后帮手数量的增加会导致端粒变短。rTL 较长的 9 天大的雏鸟在孵化后 5 年内更有可能存活。然而，在接近离巢时，实验对 rTL 没有可检测到的影响，rTL 与生存之间也没有联系。因此，这项对野生合作繁殖者的实验研究部分支持了帮手的存在对后代 rTL 的重要性，以及早期端粒长度与长期生存之间的联系。
