Department of Biological Sciences, University of Calgary, 3330 Hospital Drive, Health Science Centre 2559, Calgary, AB, Canada.
Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada.
Sci Rep. 2020 Sep 24;10(1):15626. doi: 10.1038/s41598-020-72376-x.
An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall's sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. Principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change.
了解影响产前特征的机制对于理解动物生存和繁殖成功背后的生态和进化过程的作用至关重要。尽管寄生虫对宿主适应性的负面影响是无可争议的，但我们对于生殖雌性中的寄生虫感染如何影响胎儿发育和性别分配等产前因素知之甚少。本研究使用了 Dall's 绵羊（Ovis dalli dalli）的档案数据集，该物种是一种主要依靠身体储备来度过北极冬季的资本繁殖者，我们调查了寄生虫群落对胎儿发育和性别分配的直接和间接影响。通过偏最小二乘模型分析，我们观察到寄生虫群落对胎儿发育有负面影响，主要是由线虫 Marshallagia marshalli 驱动的。主成分分析表明，寄生虫负担低且身体状况良好的母羊更容易产下雌性胎儿而非雄性胎儿。这种关联主要是由 M. marshalli 对母羊身体状况的间接影响驱动的。深入了解寄生虫群落对哺乳动物繁殖的直接和间接影响，对于理解传染病对野生动物种群的影响至关重要。对于生活在对全球气候变化影响敏感的生态系统中的物种来说，这可能尤为重要。
