van Dijk René E, Székely Tamás, Komdeur Jan, Pogány Akos, Fawcett Tim W, Weissing Franz J
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
Proc Biol Sci. 2012 May 22;279(1735):1927-36. doi: 10.1098/rspb.2011.2297. Epub 2011 Dec 21.
Eurasian penduline tits (Remiz pendulinus) have an unusually diverse breeding system consisting of frequent male and female polygamy, and uniparental care by the male or the female. Intriguingly, 30 to 40 per cent of all nests are deserted by both parents. To understand the evolution of this diverse breeding system and frequent clutch desertion, we use 6 years of field data to derive fitness expectations for males and females depending on whether or not they care for their offspring. The resulting payoff matrix corresponds to an asymmetric Snowdrift Game with two alternative evolutionarily stable strategies (ESSs): female-only and male-only care. This, however, does not explain the polymorphism in care strategies and frequent biparental desertion, because theory predicts that one of the two ESSs should have spread to fixation. Using a bootstrapping approach, we demonstrate that taking account of individual variation in payoffs explains the patterns of care better than a model based on the average population payoff matrix. In particular, a model incorporating differences in male attractiveness closely predicts the observed frequencies of male and female desertion. Our work highlights the need for a new generation of individual-based evolutionary game-theoretic models.
欧亚攀雀（Remiz pendulinus）拥有异常多样的繁殖系统，包括频繁的雄性和雌性多配偶制，以及雄性或雌性的单亲抚育。有趣的是，所有巢穴中有30%至40%被双亲遗弃。为了理解这种多样繁殖系统和频繁弃巢行为的进化过程，我们利用6年的野外数据得出了雄性和雌性的适合度期望，这取决于它们是否照顾自己的后代。由此产生的收益矩阵对应于一个非对称的雪堆博弈，有两种交替的进化稳定策略（ESSs）：仅由雌性照顾和仅由雄性照顾。然而，这并不能解释照顾策略的多态性和频繁的双亲遗弃现象，因为理论预测这两种ESSs中的一种应该已经扩散至固定状态。通过一种自展法，我们证明，考虑收益的个体差异比基于平均种群收益矩阵的模型能更好地解释抚育模式。特别是，一个纳入雄性吸引力差异的模型能紧密预测观察到的雄性和雌性遗弃频率。我们的工作强调了新一代基于个体的进化博弈论模型的必要性。
