Large Animal Research Group, Department of Zoology, University of Cambridge, Cambridge, UK.
Mammal Research Institute, University of Pretoria, Pretoria, South Africa.
J Anim Ecol. 2021 Mar;90(3):641-652. doi: 10.1111/1365-2656.13396. Epub 2020 Dec 14.
Recent comparative studies show that cooperative breeding is positively correlated with harsh and unpredictable environments and it is suggested that this association occurs because helpers buffer the negative effects of adverse ecological conditions on fitness. In the Kalahari, rainfall varies widely between- and within years, affecting primary production and the availability of the principal prey of cooperatively breeding Kalahari meerkats, Suricata suricatta. Our study aimed to establish whether the presence and number of helpers buffer the negative effects of variation in rainfall on the fecundity and body mass of breeding females, and the survival and growth of pups. We investigate the relationship between group size and variation in rainfall on dominant female fecundity, body mass, and offspring survival and growth using an additive modelling approach on 21 years of individual-based records of the life histories of individual meerkats. We show that breeding female fecundity is reduced during periods of low rainfall but that the effects of low rainfall are mitigated by increases in group size and body mass because heavier females and those in larger groups have increased fecundity and reduced interbirth intervals. Pup growth and survival are also reduced during periods of low rainfall, but only in smaller groups. Our results support the suggestion that cooperative breeding mitigates the detrimental effects of adverse environmental conditions and may enhance the capacity of species to occupy environments where food availability is low and unpredictable.
最近的比较研究表明，合作繁殖与恶劣和不可预测的环境呈正相关，有人认为这种关联是因为帮手可以缓冲不利生态条件对适应性的负面影响。在卡拉哈里沙漠，降雨量在年际和年内变化很大，影响着初级生产力和合作繁殖的卡拉哈里猫鼬（Suricata suricatta）的主要猎物的可利用性。我们的研究旨在确定帮手的存在和数量是否可以缓冲降雨量变化对繁殖雌性的繁殖力和体重、以及幼崽的存活率和生长的负面影响。我们使用个体基础记录的 21 年个体猫鼬生活史数据，采用附加模型方法，调查了群体大小与降雨量变化对优势雌性繁殖力、体重以及后代存活率和生长的关系。我们发现，繁殖雌性的繁殖力在降雨量低的时期会降低，但低降雨量的影响可以通过群体大小和体重的增加来减轻，因为体重较重的雌性和在较大群体中的雌性繁殖力更高，并且出生间隔更短。幼崽的生长和存活率也会在降雨量低的时期降低，但仅在较小的群体中。我们的研究结果支持了这样一种观点，即合作繁殖可以减轻不利环境条件的不利影响，并可能增强物种在食物供应低且不可预测的环境中生存的能力。
