Biz Luana S, Bastazini Vinicius A G, Carvalho Fernando, Ramos Pereira Maria João
Programa de Pós-graduação em Ecologia Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS) Porto Alegre Brazil.
Departamento de Zoologia, Instituto de Biociências, Bird and Mammal Evolution, Systematics and Ecology Laboratory Universidade Federal do Rio Grande do Sul Porto Alegre Brazil.
Ecol Evol. 2023 Sep 15;13(9):e10527. doi: 10.1002/ece3.10527. eCollection 2023 Sep.
Ecological interactions between parasites and their hosts play a fundamental role in evolutionary processes. Selection pressures are exerted on parasites and their hosts, usually resulting in high levels of specificity. Such is the case of ectoparasitic bat-flies, but how large-scale spatial gradients affect the dynamics of their interactions with their bat hosts is still unknown. In the present study, we investigated interaction patterns between bats and their ectoparasitic flies (Streblidae and Nycteribiidae), both presenting their peak of diversity in the Neotropical region, along a latitudinal gradient. Using network analyses and parasitic indices, grounded on the latitudinal diversity gradient pattern, we evaluated how spatial gradients affect species interactions and parasitic indices at the biogeopraphic scale, with increasing species richness in interaction networks closer to the tropics, leading to increases in network modularity, size, and specialization, and to a decrease in nesting and connectivity. We conducted a literature review, focusing on studies done in the Neotropical region, and own data. We obtained a bat richness of 97 species parasitized by 128 species of ectoparasitic flies, distributed into 57 interaction networks between latitudes 29° S and 19° N in the Neotropic. Network metrics and parasitic indices varied along the latitudinal gradient, with changes in the richness of bats and their ectoparasitic flies and in the structure of their interactions; network specialization, modularity, and connectance increase with latitude, while network size decreases with latitude. Regions closer to the equator had higher parasite loads. Our results show that interaction network metrics present a latitudinal gradient and that such interactions, when observed at a local scale, hide variations that only become perceptible at larger scales. In this way, ectoparasites such as bat flies are not only influenced by the ecology and biology of their hosts, but also by other environmental factors acting directly on their distribution and survival.
寄生虫与其宿主之间的生态相互作用在进化过程中起着基础性作用。寄生虫及其宿主会受到选择压力的影响，通常会导致高度的特异性。外寄生性蝙蝠蝇就是这样，但大规模空间梯度如何影响它们与蝙蝠宿主相互作用的动态仍不清楚。在本研究中，我们沿着纬度梯度调查了蝙蝠与其外寄生性蝇类（蝠蝇科和蛛蝇科）之间的相互作用模式，这两类生物在新热带地区的多样性均达到峰值。基于纬度多样性梯度模式，我们使用网络分析和寄生指数，评估了空间梯度如何在生物地理尺度上影响物种相互作用和寄生指数，随着靠近热带地区的相互作用网络中物种丰富度增加，导致网络模块性、规模和专业化程度提高，嵌套性和连通性降低。我们进行了文献综述，重点关注在新热带地区开展的研究以及我们自己的数据。我们获得了97种蝙蝠被128种外寄生性蝇类寄生的信息，这些分布在新热带地区南纬29°至北纬19°之间的57个相互作用网络中。网络指标和寄生指数沿着纬度梯度变化，蝙蝠及其外寄生性蝇类的丰富度以及它们相互作用的结构也发生了变化；网络专业化、模块性和连通性随纬度增加，而网络规模随纬度减小。更靠近赤道的地区寄生虫负荷更高。我们的结果表明，相互作用网络指标呈现出纬度梯度，并且这种相互作用在局部尺度观察时，隐藏了只有在更大尺度上才会显现的变化。这样一来，像蝙蝠蝇这样的外寄生虫不仅受到其宿主的生态和生物学影响，还受到直接作用于它们分布和生存的其他环境因素的影响。
