Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA.
Cary Institute of Ecosystem Studies, Millbrook, NY, USA.
Proc Biol Sci. 2021 Nov 10;288(1962):20211942. doi: 10.1098/rspb.2021.1942. Epub 2021 Nov 3.
Physical impairments are widely assumed to reduce the viability of individual animals, but their impacts on individuals within natural populations of vertebrates are rarely quantified. By monitoring wild populations of white-footed mice over 26 years, we assessed whether missing or deformed limbs, tail or eyes influenced the survival, body mass, movement and ectoparasite burden of their bearers. Of the 27 244 individuals monitored, 543 (2%) had visible physical impairments. Persistence times (survival) were similar between mice with and without impairments. Mice with eye and tail impairments had 5% and 6% greater mass, respectively, than unimpaired mice. Mice with tail impairments had larger home ranges than did unimpaired mice. Burdens of black-legged ticks () were higher among mice with tail and limb impairments while burdens of bot fly larvae () were higher among mice with cataracts compared to mice without impairments. Our findings do not support the presupposition that physical impairments reduce viability in their bearers and are inconsistent with the devaluation of impaired individuals that pervaded early thinking in evolutionary biology.
身体损伤被广泛认为会降低个体动物的生存能力，但它们对脊椎动物自然种群中个体的影响却很少被量化。通过对 26 年来的白足鼠野生种群进行监测，我们评估了缺失或畸形的四肢、尾巴或眼睛是否会影响其携带者的生存、体重、运动和外寄生虫负担。在监测到的 27244 只个体中，有 543 只（2%）存在明显的身体损伤。有损伤和无损伤的老鼠的持续时间（生存）相似。眼睛和尾巴受损的老鼠比未受损的老鼠分别增加了 5%和 6%的体重。尾巴受损的老鼠的活动范围比未受损的老鼠大。尾巴和四肢受损的老鼠身上的黑腿蜱（）的负担更高，而白内障老鼠身上的马蝇幼虫（）的负担比未受损的老鼠更高。我们的研究结果不支持身体损伤会降低其携带者生存能力的假设，也与进化生物学早期思维中普遍存在的对受损个体的贬低不一致。
