Latitudinal migration increases fitness of migrants by allowing them to exploit favorable conditions in nonadjacent geographic regions. Other consequences also may follow, such as interactions with parasites. Migrants may have lower parasite prevalence and abundance than resident individuals because of their ability to abandon infested areas or due to mortality of highly infested hosts. To further understand whether variation in ectoparasite loads is influenced by migration, we investigated whether prevalence and abundance of two species of obligate ectoparasites, the wing mite Periglischrus paracaligus (Mesostigmata: Spinturnicidae) and the bat fly Nycterophilia coxata (Diptera: Streblidae, Nycterophiliinae), of the lesser long-nosed bat, Leptonycteris yerbabuenae, varied between migratory and resident populations throughout their range in Mexico. We examined the presence or absence of migratory behavior, as well as sex and reproductive status of the host because ectoparasitism differentially affects the sexes. Our results showed that the prevalence of both ectoparasites did not vary between migrant and resident females or males, but abundance of the wing mite P. paracaligus was lower in migrant females compared with resident females, with an important influence from the reproductive status of the host. A partial negative relationship between ectoparasite loads and latitudinal migration therefore was demonstrated.

中文翻译：

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横向迁移是否代表了在 Leptonycteris yerbabuenae (Chiroptera) 中减少外寄生负荷的优势？

横向迁徙通过让迁徙者利用不相邻地理区域的有利条件来提高迁徙者的适应度。其他后果也可能随之而来，例如与寄生虫的相互作用。移民的寄生虫流行率和丰度可能低于居民个体，因为他们能够放弃受感染的地区或由于高感染宿主的死亡。为了进一步了解外寄生物负荷的变化是否受迁移的影响，我们调查了两种专性外寄生物的流行和丰度，翼螨 Periglischrus paracaligus（Mesostigmata：Spinturnicidae）和蝙蝠蝇 Nycterophilia coxata（双翅目：Streblidae，Nycterophilinae）较小的长鼻蝙蝠中的 Leptonycteris yerbabuenae 在墨西哥的整个分布范围内在迁徙种群和常住种群之间存在差异。我们检查了迁徙行为的存在与否，以及宿主的性别和生殖状态，因为外寄生对性别的影响不同。我们的结果表明，两种外寄生虫的患病率在迁徙和常住雌性或雄性之间没有差异，但与常驻雌性相比，迁徙雌性中翼螨 P. paracaligus 的丰度较低，这受到宿主生殖状态的重要影响. 因此，证明了外寄生虫负荷与纬度迁移之间存在部分负相关。我们的结果表明，两种外寄生虫的患病率在迁徙和常住雌性或雄性之间没有差异，但与常驻雌性相比，迁徙雌性中翼螨 P. paracaligus 的丰度较低，这受到宿主生殖状态的重要影响. 因此，证明了外寄生虫负荷与纬度迁移之间存在部分负相关。我们的结果表明，两种外寄生虫的患病率在迁徙和常住雌性或雄性之间没有差异，但与常驻雌性相比，迁徙雌性中翼螨 P. paracaligus 的丰度较低，这受到宿主生殖状态的重要影响. 因此，证明了外寄生虫负荷与纬度迁移之间存在部分负相关。