Data from: Sex-based population structure of ectoparasites from Neotropical bats

The structure and composition of populations may be molded by multiple evolutionary and ecological mechanisms, with natural selection affecting sex ratios, as well as the distributions of each sex throughout the environment. To address sex-based aspects of population structure, I evaluated sex ratios, co-occurrence of the sexes, correlations of abundance of the sexes, and dispersion of individuals of each sex for each of 34 host-ectoparasite associations from Paraguayan bats. Of the 34 host-ectoparasite associations, 23 exhibited positive co-occurrence, 27 exhibited positive correlation of abundances, 4 exhibited male sex bias, 1 exhibited female sex bias, 27 had clumped distributions of males, and 26 had clumped distributions of females. No associations exhibited negative co-occurrence, negative correlation of abundance, or hyper-dispersed males or females. There was no evidence for sexual segregation, sex-based niche partitioning, or intrasexual selection in any host-ectoparasite association. Previously proposed mechanisms (e.g. pre-partum sex bias, local mate competition, or mortality from host grooming) fail to explain observed patterns of sex bias. For ectoparasites of hosts that occupy permanent roost sites, sex-specific behaviour related to reproduction may make females more susceptible to off-host predation and less likely to be present in samples from bats captured away from the roost.种群的结构与组成可受多种进化与生态机制共同塑造，其中自然选择既会影响种群性比，也会调控两性在环境中的分布格局。为探究种群结构的性别相关特征，本研究针对巴拉圭蝙蝠的34组宿主-外寄生物关联（host-ectoparasite associations）开展分析，依次评估了各组的性比、两性共存情况、两性丰度相关性，以及各性别个体的空间分布离散度。在这34组宿主-外寄生物关联中，23组呈现两性正共存格局，27组表现出两性丰度正相关，4组存在雄性性别偏倚，1组存在雌性性别偏倚；27组的雄性个体呈聚集分布，26组的雌性个体呈聚集分布。未发现任何一组存在两性负共存、丰度负相关，或雄性/雌性个体呈超离散分布的情况。所有宿主-外寄生物关联中均未发现性隔离、基于性别的生态位分化，或性内选择的相关证据。此前提出的多种解释机制（如产前性别偏倚、局部配偶竞争，或宿主理毛导致的死亡）均无法合理解释本次观测到的性别偏倚格局。对于栖息于永久性栖息场所的宿主外寄生物而言，与繁殖相关的性别特异性行为可能会使雌性更易在离开宿主后遭遇捕食，因此在远离栖息场所捕获的蝙蝠样本中，雌性外寄生物的检出概率更低。