University of North Carolina Wilmington, Department of Biology and Marine Biology, Center for Marine Science, Wilmington, NC 28403, USA.
Sci Rep. 2016 Jul 1;6:29237. doi: 10.1038/srep29237.
In organisms with temperature-dependent sex determination, the incubation environment plays a key role in determining offspring sex ratios. Given that global temperatures have warmed approximately 0.6 °C in the last century, it is necessary to consider how organisms will adjust to climate change. To better understand the degree to which mothers influence the sex ratios of their offspring, we use 24 years of nesting data for individual female loggerhead sea turtles (Caretta caretta) observed on Bald Head Island, North Carolina. We find that maternal identity is the best predictor of nest sex ratio in univariate and multivariate predictive models. We find significant variability in estimated nest sex ratios among mothers, but a high degree of consistency within mothers, despite substantial spatial and temporal thermal variation. Our results suggest that individual differences in nesting preferences are the main driver behind divergences in nest sex ratios. As such, a female's ability to plastically adjust her nest sex ratios in response to environmental conditions is constrained, potentially limiting how individuals behaviorally mitigate the effects of environmental change. Given that many loggerhead populations already show female-biased offspring sex ratios, understanding maternal behavioral responses is critical for predicting the future of long-lived species vulnerable to extinction.
在温度依赖型性别决定的生物中，孵化环境在决定后代性别比例方面起着关键作用。鉴于过去一个世纪全球气温已经上升了约 0.6°C，有必要考虑生物体将如何适应气候变化。为了更好地了解母亲对其后代性别比例的影响程度，我们利用北卡罗来纳州光头岛（Bald Head Island）对 24 年个体红海龟（Caretta caretta）筑巢数据进行了研究。我们发现，在单变量和多变量预测模型中，母体身份是巢性别比例的最佳预测因子。我们发现，尽管存在很大的空间和时间温度变化，但母亲之间的估计巢性别比例存在显著差异，但母亲内部的一致性很高。我们的研究结果表明，筑巢偏好的个体差异是巢性别比例差异的主要驱动因素。因此，女性根据环境条件灵活调整巢性别比例的能力受到限制，这可能限制了个体行为缓解环境变化影响的程度。鉴于许多红海龟种群已经表现出雌性偏多的后代性别比例，了解母体的行为反应对于预测易灭绝的长寿物种的未来至关重要。
