Albery Gregory F, Sweeny Amy R, Corripio-Miyar Yolanda, Evans Mike J, Hayward Adam D, Pemberton Josephine M, Pilkington Jill G, Nussey Daniel H
School of Natural Sciences, Trinity College Dublin, Dublin, Republic of Ireland.
Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, UK.
Parasitology. 2025 Jun;152(7):715-723. doi: 10.1017/S0031182025100383.
High density should drive greater parasite exposure. However, evidence linking density with infection generally uses density proxies or measures of population size, rather than measures of individuals per space within a continuous population. We used a long-term study of wild sheep to link within-population spatiotemporal variation in host density with individual parasite counts. Although four parasites exhibited strong positive relationships with local density, these relationships were mostly restricted to juveniles and faded in adults. Furthermore, one ectoparasite showed strong negative relationships across all age classes. In contrast, population size - a measure of global density - had limited explanatory power, and its effects did not remove those of spatial density, but were distinct. These results indicate that local and global density can exhibit diverse and contrasting effects on infection within populations. Spatial measures of within-population local density may provide substantial additional insight to temporal metrics based on population size, and investigating them more widely could be revealing.
高密度应会导致更高的寄生虫暴露风险。然而，将密度与感染联系起来的证据通常使用密度替代指标或种群规模的测量方法，而非连续种群中单位空间内个体数量的测量方法。我们利用一项对野生绵羊的长期研究，将宿主密度在种群内的时空变化与个体寄生虫计数联系起来。尽管四种寄生虫与局部密度呈现出强烈的正相关关系，但这些关系大多仅限于幼年绵羊，在成年绵羊中则逐渐减弱。此外，一种体外寄生虫在所有年龄组中都呈现出强烈的负相关关系。相比之下，种群规模——一种全球密度的测量指标——的解释力有限，其影响并不能消除空间密度的影响，而是与之不同。这些结果表明，局部密度和全球密度对种群内感染可能呈现出多样且相反的影响。种群内局部密度的空间测量方法可能会为基于种群规模的时间指标提供大量额外的见解，更广泛地研究这些方法可能会有新的发现。
