The genetic structure of populations can be both a cause and a consequence of ecological interactions. For parasites, genetic structure may be a consequence of preferences for host species or of mating behaviour. Conversely, genetic structure can influence where conspecific interactions among parasites lay on a spectrum from cooperation to conflict. We used microsatellite loci to characterize the genetic structure of a population of the socially parasitic dulotic (aka “slave‐making”) ant (Polyergus mexicanus ), which is known for its host‐specificity and conspecific aggression. First, we assessed whether the pattern of host species use by the parasite has influenced parasite population structure. We found that host species use was correlated with subpopulation structure, but this correlation was imperfect: some subpopulations used one host species nearly exclusively, while others used several. Second, we examined the viscosity of the parasite population by measuring the relatedness of pairs of neighbouring parasitic ant colonies at varying distances from each other. Although natural history observations of local dispersal by queens suggested the potential for viscosity, there was no strong correlation between relatedness and distance between colonies. However, 35% of colonies had a closely related neighbouring colony, indicating that kinship could potentially affect the nature of some interactions between colonies of this social parasite. Our findings confirm that ecological forces like host species selection can shape the genetic structure of parasite populations, and that such genetic structure has the potential to influence parasite‐parasite interactions in social parasites via inclusive fitness.

中文翻译：

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具有社会寄生性的墨西哥蚂蚁具有与宿主相关的遗传种群结构和相关的邻近菌落。

种群的遗传结构既可以是生态相互作用的原因，也可以是生态相互作用的结果。对于寄生虫，遗传结构可能是宿主物种偏好或交配行为的结果。相反，遗传结构可以影响寄生虫之间的种间相互作用在从合作到冲突的整个范围内。我们用微卫星基因座表征社会寄生dulotic（又名“从属制作”）蚁群体的遗传结构（悍蚁mexicanus），以其宿主特异性和同种侵略性而闻名。首先，我们评估了寄生虫利用宿主物种的模式是否影响了寄生虫种群结构。我们发现宿主物种的使用与亚种群结构相关，但这种关联并不完美：一些亚种群几乎只使用一种宿主物种，而另一些则使用几种。其次，我们通过测量成对的相邻寄生蚂蚁菌落对之间的距离，来检测寄生虫种群的黏性。尽管皇后对自然扩散的自然历史观察表明存在潜在的黏性，但相关性与菌落之间的距离之间并没有很强的相关性。但是，有35％的殖民地有密切相关的邻近殖民地，表明亲属关系可能会影响该社交寄生虫的菌落之间某些相互作用的性质。我们的发现证实，诸如寄主物种选择之类的生态力量可以塑造寄生虫种群的遗传结构，并且这种遗传结构具有通过包容性适应影响寄生虫在社会寄生虫中相互作用的潜力。