Abstract

In group-living animals, the social environment is thought to affect the probability of parasite transmission. Here, I investigate relationships between social behaviour and gastrointestinal parasite product excretion in the carrion crow (Corvus corone). Individuals from a population of non-cooperatively breeding carrion crows excreted less samples containing coccidian oocysts when kept in larger groups (8 or 9 individuals) compared to those individuals kept in smaller groups (2 or 3 individuals). Lower-ranking individuals excreted more samples containing parasite oocysts compared to higher-ranking individuals. The strength of affiliative relationships and number of related individuals in the group did not relate to the proportion of droppings containing coccidian oocysts. The present results confirm an association between social environment and parasite excretion patterns in carrion crows, but the patterns described in the present study differ from previously published data derived from a group of cooperatively breeding crows. This illustrates that differences between the social systems of carrion crows might result in different associations between the social environment and parasite product excretion patterns.

Significance statement

One major cost of group living is increased susceptibility to parasites. Not all individuals are affected by this in the same way. A better understanding of the relationship between social behaviour and parasite burden can help to better understand evolution of group living. I investigate associations between dominance rank, affiliative relationships, group size, and gastrointestinal parasite product excretion in a group of captive carrion crows. Lower-ranking individuals excreted more samples containing parasite oocysts compared to higher-ranking individuals, confirming an association between social relationships and parasite excretion patterns.

中文翻译：

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一组非合作繁殖的腐肉乌鸦中社会因素与胃肠道寄生虫产品排泄之间的关联

摘要

在集体生活的动物中，人们认为社会环境会影响寄生虫传播的可能性。在这里，我调查了腐肉乌鸦（Corvus corone）中社交行为与胃肠道寄生虫产品排泄之间的关系。）。与分成小群（2或3个）的个体相比，以大群（8或9个个体）的个体，非合作繁殖的腐肉乌鸦群体的排泄出的样本较少，含有球虫卵囊。与等级较高的人相比，等级较低的人排泄了更多的含有寄生虫卵囊的样品。亲属关系的强度和相关个体的数量与包含球虫卵囊的粪便的比例无关。目前的结果证实了社会环境与腐肉乌鸦中寄生虫排泄模式之间的关联，但是本研究中描述的模式与先前发表的来自一组合作繁殖的乌鸦的数据不同。

重要性声明

群体生活的主要成本之一是对寄生虫的敏感性增加。并非所有个人都以相同的方式受到此影响。更好地理解社会行为与寄生虫负担之间的关系可以帮助更好地了解群体生活的演变。我调查了一群圈养腐尸乌鸦中支配地位，亲属关系，群体规模和胃肠道寄生虫产品排泄之间的关联。与等级较高的人相比，等级较低的人排泄了更多的含有寄生虫卵囊的样品，这证实了社会关系与寄生虫的排泄方式之间存在关联。