Graduate Program in Ecology and Evolution, SUNY Stony Brook University, Stony Brook, New York, USA.
Department of Anthropology, Boston University, Boston, Massachusetts, USA.
Am J Biol Anthropol. 2024 Nov;185(3):e25035. doi: 10.1002/ajpa.25035. Epub 2024 Oct 1.
Allomaternal care (AMC) is suggested to be energetically beneficial to mothers and costly to allomothers. However, among primates, AMC is a heterogeneous phenomenon and its implications are less clear especially in female dispersal species. Here, we investigated infant care in a female dispersal species, Phayre's leaf monkeys (Trachypithecus phayrei crepusculus), to evaluate whether mothers were constrained by infant care and benefitted energetically from AMC, whether AMC was energetically costly for allomothers and how maternal experience was associated with AMC.
Data were collected via instantaneous focal animal sampling between 2004 and 2005 for juvenile and adult females (N = 18) from two groups at the Phu Khieo Wildlife Sanctuary, Thailand (440 h). We used generalized linear mixed models to determine how infant care during the first month after birth affected the time mothers and allomothers spent feeding, socializing, resting, and locomoting and how AMC varied.
In the first month, infants spent 26% of their time with an allomother. We found no differences in mothers' overall activity before versus after birth, although mothers fed significantly more and rested less when without their infant. Allomothers fed and rested less when with an infant. AMC varied between 0.0% and 20.5%, with immature females being most active.
Mothers appear to benefit energetically from AMC such that their overall activity after birth remained unchanged. Costs and benefits for allomothers seem to be variable. Some very active immature females may be benefitting from learning-to-mother. The overall low cost of AMC may facilitate a reciprocal social network among unrelated females.
异亲抚育（AMC）被认为对母亲具有能量效益，对代育者具有成本。然而，在灵长类动物中，AMC 是一种异质现象，其影响尚不清楚，尤其是在雌性扩散物种中。在这里，我们研究了雌性扩散物种菲氏叶猴（Trachypithecus phayrei crepusculus）的婴儿护理，以评估母亲是否受到婴儿护理的限制，是否从 AME 中获得能量效益，代育者是否因 AMC 而付出能量代价，以及母性经验如何与 AMC 相关。
数据通过瞬时焦点动物采样在 2004 年至 2005 年之间在泰国 Phu Khieo 野生动物保护区的两个群体中收集（440 小时），用于研究幼崽和成年雌性（N=18）。我们使用广义线性混合模型来确定婴儿在出生后第一个月内接受的护理如何影响母亲和代育者花费的时间进行喂养、社交、休息和运动，以及 AMC 的变化情况。
在第一个月，婴儿有 26%的时间与代育者在一起。我们没有发现母亲在出生前后整体活动的差异，尽管在没有婴儿时，母亲的喂食显著增加，休息减少。当有婴儿时，代育者的喂食和休息减少。AMC 变化范围为 0.0%至 20.5%，其中未成熟的雌性最活跃。
母亲似乎从 AMC 中获得了能量效益，因此她们出生后的整体活动保持不变。代育者的成本和效益似乎是可变的。一些非常活跃的未成熟雌性可能从学习养育中受益。总体而言，AMC 的低代价可能促进了无关雌性之间的互惠社交网络。
