Menário Costa Weliton, King Wendy J, Bonnet Timothée, Festa-Bianchet Marco, Kruuk Loeske E B
Division of Ecology & Evolution, Research School of Biology, Australian National University, Canberra Australian Capital Territory, 2601, Australia.
Département de biologie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec, J1K 2R1, Canada.
Behav Ecol. 2023 Sep 14;34(6):1002-1012. doi: 10.1093/beheco/arad070. eCollection 2023 Nov-Dec.
Individual behavior varies for many reasons, but how early in life are such differences apparent, and are they under selection? We investigated variation in early-life behavior in a wild eastern gray kangaroo () population, and quantified associations of behavior with early survival. Behavior of young was measured while still in the pouch and as subadults, and survival to weaning was monitored. We found consistent variation between offspring of different mothers in levels of activity at the pouch stage, in flight initiation distance (FID) as subadults, and in subadult survival, indicating similarity between siblings. There was no evidence of covariance between the measures of behavior at the pouch young versus subadult stages, nor of covariance of the early-life behavioral traits with subadult survival. However, there was a strong covariance between FIDs of mothers and those of their offspring tested at different times. Further, of the total repeatability of subadult FID (51.5%), more than half could be attributed to differences between offspring of different mothers. Our results indicate that 1) behavioral variation is apparent at a very early stage of development (still in the pouch in the case of this marsupial); 2) between-mother differences can explain much of the repeatability (or "personality") of juvenile behavior; and 3) mothers and offspring exhibit similar behavioral responses to stimuli. However, 4) we found no evidence of selection via covariance between early-life or maternal behavioral traits and juvenile survival in this wild marsupial.
个体行为因多种原因而有所不同，但这些差异在生命早期多早出现，以及它们是否受到选择作用呢？我们调查了野生东部灰袋鼠种群早期行为的变化，并量化了行为与早期生存之间的关联。在幼崽还在育儿袋中以及成为亚成体时测量其行为，并监测其断奶后的生存情况。我们发现不同母亲的后代在育儿袋阶段的活动水平、亚成体的飞行起始距离（FID）以及亚成体生存方面存在一致的差异，这表明同胞之间具有相似性。没有证据表明育儿袋中的幼崽与亚成体阶段的行为测量之间存在协方差，也没有证据表明早期行为特征与亚成体生存之间存在协方差。然而，母亲及其后代在不同时间测试的FID之间存在很强的协方差。此外，在亚成体FID的总重复性（51.5%）中，超过一半可归因于不同母亲的后代之间的差异。我们的结果表明：1）行为差异在发育的非常早期阶段就很明显（在这种有袋动物中是还在育儿袋中时）；2）母亲之间的差异可以解释幼崽行为的大部分重复性（或“个性”）；3）母亲和后代对刺激表现出相似的行为反应。然而，4）在这种野生有袋动物中，我们没有发现通过早期或母体行为特征与幼崽生存之间的协方差进行选择的证据。
