Roy Michèle, Brodeur Jacques, Cloutier Conrad
Direction des services technologiques, Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec, 2700 rue Einstein, Sainte-Foy, Quebec, G1P 3W8, Canada.
Oecologia. 2003 Apr;135(2):322-6. doi: 10.1007/s00442-002-1160-9. Epub 2003 Feb 26.
Although temperature is the most important environmental factor regulating arthropod development and reproduction, its influence on sex allocation in haplodiploid arthropods remains largely unexplored. We investigated under laboratory conditions how maternal age and temperature mediate offspring sex ratio of the spider mite Tetranychus mcdanieli (Acari: Tetranychidae). Over nine temperature regimes, female-biased sex ratios were consistently observed, varying from 57 to 87% among progeny produced over lifetime. Spider mite sex ratio was affected by maternal age: more male progeny were produced at both the beginning and the end of the female lifespan, yielding a dome shaped curvilinear relationship. This pattern of variation with age probably results from constraints on using sperm at young ages and sperm depletion or viability at older ages. We found a significant curvilinear relationship between temperature and sex ratio. The proportion of female offspring was lowest at intermediate temperatures and highest at extreme temperatures. We suggest that increased female-biased sex ratio at extreme temperatures is an evolutionary response of spider mites to deteriorating habitats as, in the Tetranychidae, females have better capacities than males to disperse and survive under harsh conditions.
尽管温度是调节节肢动物发育和繁殖的最重要环境因素，但其对单倍二倍体节肢动物性分配的影响在很大程度上仍未得到探索。我们在实验室条件下研究了母体年龄和温度如何影响麦氏叶螨（Tetranychus mcdanieli，蜱螨亚纲：叶螨科）后代的性别比例。在九种温度条件下，始终观察到雌性偏向的性别比例，在整个生命周期产生的后代中，雌性比例从57%到87%不等。叶螨的性别比例受母体年龄影响：在雌性寿命开始和结束时产生的雄性后代更多，呈现出圆顶形的曲线关系。这种随年龄变化的模式可能是由于幼龄时使用精子受到限制以及老龄时精子耗尽或活力下降所致。我们发现温度与性别比例之间存在显著的曲线关系。雌性后代的比例在中等温度下最低，在极端温度下最高。我们认为，在极端温度下雌性偏向的性别比例增加是叶螨对栖息地恶化的一种进化反应，因为在叶螨科中，雌性在恶劣条件下比雄性具有更强的扩散和生存能力。
