Ecology & Evolutionary Biology Department, The University of Kansas, Lawrence, KS 66045-7534, USA.
Mol Ecol. 2012 Feb;21(3):532-40. doi: 10.1111/j.1365-294X.2011.05323.x. Epub 2011 Oct 21.
Social behaviour was proposed as a density-dependent intrinsic mechanism that could regulate an animal population by affecting reproduction and dispersal. Populations of the polygynous yellow-bellied marmot (Marmota flaviventris) fluctuate widely from year to year primarily driven by the number of weaned young. The temporal variation in projected population growth rate was driven mainly by changes in the age of first reproduction and fertility, which are affected by reproductive suppression. Dispersal is unrelated to population density, or the presence of the father; hence, neither of these limits population growth or acts as an intrinsic mechanism of population regulation; overall, intrinsic regulation seems unlikely. Sociality affects the likelihood of reproduction in that the annual probability of reproducing and the lifetime number of offspring are decreased by the number of older females and by the number of same-aged females present, but are increased by the number of younger adult females present. Recruitment of a yearling female is most likely when her mother is present; recruitment of philopatric females is much more important than immigration for increasing the number of adult female residents. Predation and overwinter mortality are the major factors limiting the number of resident adults. Social behaviour is not directed towards population regulation, but is best interpreted as functioning to maximize direct fitness.
社会行为被认为是一种密度依赖的内在机制，可以通过影响繁殖和扩散来调节动物种群。多配偶制的黄腹旱獭（Marmota flaviventris）种群的数量波动很大，主要是由断奶幼仔的数量驱动的。预测种群增长率的时间变化主要是由首次繁殖和生育年龄的变化驱动的，这受到生殖抑制的影响。扩散与种群密度或父亲的存在无关；因此，这两者都不会限制种群增长，也不会成为种群调节的内在机制；总的来说，内在调节似乎不太可能。社会性影响繁殖的可能性，因为繁殖的年度可能性和终生后代数量会随着年龄较大的雌性数量和同年龄雌性数量的增加而减少，但会随着年轻成年雌性数量的增加而增加。当一年生雌性旱獭的母亲在场时，其繁殖的可能性最大；对于增加成年雌性居民的数量，同种雌性旱獭的繁殖比移民更为重要。捕食和越冬死亡率是限制成年居民数量的主要因素。社会行为不是为了调节种群，而是最好被解释为最大限度地提高直接适应度。
