Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, 3498838, Israel.
Department of Biology and Environment, University of Haifa at Oranim, Tivon, 36006, Israel.
Biol Rev Camb Philos Soc. 2023 Dec;98(6):1845-1861. doi: 10.1111/brv.12986. Epub 2023 Jun 18.
Cooperative breeding (i.e. when alloparents care for the offspring of other group members) has been studied for nearly a century. Yet, inconsistent definitions of this breeding system still hamper comparative research. Here, we identify two major inconsistencies, discuss their consequences and propose a way forward. First, some researchers restrict the term 'cooperative breeding' to species with non-breeding alloparents. We show that such restrictive definitions lack distinct quantitative criteria to define non-breeding alloparents. This ambiguity, we argue, reflects the reproductive-sharing continuum among cooperatively breeding species. We therefore suggest that cooperative breeding should not be restricted to the few species with extreme reproductive skew and should be defined independent of the reproductive status of alloparents. Second, definitions rarely specify the type, extent and prevalence of alloparental care required to classify species as cooperative breeders. We thus analysed published data to propose qualitative and quantitative criteria for alloparental care. We conclude by proposing the following operational definition: cooperative breeding is a reproductive system where >5% of broods/litters in at least one population receive species-typical parental care and conspecifics provide proactive alloparental care that fulfils >5% of at least one type of the offspring's needs. This operational definition is designed to increase comparability across species and disciplines while allowing to study the intriguing phenomenon of cooperative breeding as a behaviour with multiple dimensions.
合作繁殖（即非亲代照顾其他群体成员的后代）已经研究了近一个世纪。然而，这种繁殖系统的不一致定义仍然阻碍了比较研究。在这里，我们确定了两个主要的不一致之处，讨论了它们的后果，并提出了一种前进的方法。首先，一些研究人员将“合作繁殖”一词限制在没有繁殖的非亲代的物种上。我们表明，这种限制性的定义缺乏明确的定量标准来定义没有繁殖能力的非亲代。我们认为，这种模糊性反映了合作繁殖物种之间的生殖共享连续体。因此，我们建议合作繁殖不应仅限于少数具有极端生殖偏斜的物种，并且应该独立于非亲代的生殖状态来定义。其次，定义很少指定分类为合作繁殖者所需的非亲代照顾的类型、程度和普遍性。因此，我们分析了已发表的数据，提出了非亲代照顾的定性和定量标准。最后，我们提出以下操作定义：合作繁殖是一种生殖系统，其中至少有一个种群中超过 5%的窝/幼崽接受了物种典型的亲代照顾，并且同种个体提供了积极的非亲代照顾，满足了至少一种类型的后代需求的 5%以上。这个操作定义旨在增加跨物种和学科的可比性，同时允许研究合作繁殖作为一种具有多个维度的行为的有趣现象。
