Laboratório de Ciências Ambientais, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil.
J Evol Biol. 2019 Nov;32(11):1207-1229. doi: 10.1111/jeb.13522. Epub 2019 Sep 15.
The measurement of fitness in wild populations is a challenging task, and a number of proxies have been proposed with different degrees of success. Developmental instability/stability (DI) is an organismal property associated with variance in bilateral asymmetry (fluctuating asymmetry-FA) and a correlated effect on fitness. This study provides evidence to corroborate the hypothesis that asymmetry partly reflects DI and is correlated with a reduction in fitness measured by survival and reproduction in bats. We studied two colonies of the bat Carollia perspicillata in southeastern Brazil over 5 years, marking and recapturing individuals. Gaussian mixture models for signed Forearm Asymmetry (ForA) distribution indicated that ~20% of asymmetry variation was due to DI heterogeneity among individuals. ForA, body condition (Scaled Mass Index-SMI) and Forearm Length (ForL) were used as predictors of survival probability in Cormack-Jolly-Seber models. Asymmetry was negatively associated with survival, whereas SMI and ForL were positively associated. The male C. perspicillata defend sites within the roost that are favoured by female harems, but there are mating opportunities for bachelor males, leading to both territorial disputes and sperm competition. As predicted by sexual selection, ForA was negatively associated with relative Testicle Length, a measure of reproductive potential. In females, ForA was negatively associated with the probability of two pregnancies (as opposed to one) in a given breeding season. The effect magnitudes and directions of associations suggest that asymmetry, even though not perfectly reflecting DI variation, is a useful predictor for fitness components in C. perspicillata.
在野外种群中测量适合度是一项具有挑战性的任务，已经提出了许多替代方法，其成功程度各不相同。发育不稳定性/稳定性（DI）是一种与双侧不对称性（波动不对称性-FA）的变化相关的生物体特性，并且对适合度有相关影响。本研究提供了证据支持这样的假设，即不对称性部分反映了 DI，并且与通过蝙蝠的生存和繁殖来衡量的适合度降低有关。我们在巴西东南部研究了两个 Carollia perspicillata 蝙蝠群，标记并重新捕获个体。签名前臂不对称（ForA）分布的高斯混合模型表明，约 20%的不对称性变化归因于个体之间的 DI 异质性。ForA、身体状况（标准化质量指数-SMI）和前臂长度（ForL）被用作 Cormack-Jolly-Seber 模型中生存概率的预测因子。不对称性与存活率呈负相关，而 SMI 和 ForL 与存活率呈正相关。雄性 C. perspicillata 会在栖息地内保卫雌性群体所喜欢的栖息地，但也有单身雄性的交配机会，导致领地争端和精子竞争。正如性选择所预测的那样，ForA 与相对睾丸长度呈负相关，睾丸长度是生殖潜力的一个衡量标准。在雌性中，ForA 与给定繁殖季节中两次怀孕的可能性（而不是一次）呈负相关。关联的大小和方向表明，尽管不对称性不能完全反映 DI 变化，但它是 C. perspicillata 适合度成分的有用预测指标。
