Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
Proc Biol Sci. 2012 Oct 7;279(1744):4065-70. doi: 10.1098/rspb.2012.1433. Epub 2012 Aug 8.
While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders.
虽然合作繁殖系统（非繁殖助手参与养育由占主导地位的雌性所产的幼崽）的进化仅限于社会一夫一妻制的交配系统，在这些系统中，群体成员之间的相关系数通常较高，但并非所有一夫一妻制的谱系都产生了具有合作繁殖系统的物种，这表明其他因素限制了合作繁殖的进化。先前的研究表明，包括寿命在内的生活史参数可能限制了合作繁殖的进化。在这里，我们表明，哺乳动物进化枝中的合作繁殖的转变仅限于雌性每次生育产多胎的谱系。我们没有发现寿命或其他生活史参数的影响的支持。我们认为，合作繁殖的进化仅限于一夫一妻制的谱系，在这些谱系中，助手有可能增加繁殖者的繁殖输出。
