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Network and parasitological analyses reveal latitudinal gradient in bats-ectoparasitic flies interactions across the Neotropic
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  • Luana da Silva Biz,
  • Vinicius Bastazini,
  • Fernando Carvalho,
  • Maria Ramos Pereira
Luana da Silva Biz
Universidade Federal do Rio Grande do Sul

Corresponding Author:[email protected]

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Vinicius Bastazini
University of Évora
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Fernando Carvalho
Universidade do Extremo Sul Catarinense
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Maria Ramos Pereira
Universidade Federal do Rio Grande do Sul
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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 theory, we evaluated how spatial gradients affect species interactions and parasitic indices at the macroscale level, predicting that interaction networks should become richer in species, leading to increases in network modularity, size, and specialization, and to a decrease in nestedness and connectance. We conducted a literature review, focusing on studies done in the Neotropical region, and data of our own authorship. We obtained a richness of 97 species of bats parasitized by 128 species of ectoparasitic flies, distributed into 57 interaction networks between latitudes 29ºS and 19ºN in the Neotropic. Network metrics and parasitic indices varied along the latitudinal gradient, with changes in 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 networks 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 by other environmental factors acting directly on their distribution and survival.
26 May 2023Submitted to Ecology and Evolution
14 Jun 2023Assigned to Editor
14 Jun 2023Submission Checks Completed
14 Jun 2023Review(s) Completed, Editorial Evaluation Pending
04 Jul 2023Editorial Decision: Revise Minor
29 Aug 20231st Revision Received
30 Aug 2023Submission Checks Completed
30 Aug 2023Assigned to Editor
30 Aug 2023Review(s) Completed, Editorial Evaluation Pending
30 Aug 2023Editorial Decision: Accept