Anthropization Affects the Assembly of Bat-Bat Fly Interaction Networks

Increasing anthropization is detrimental to the natural environment and the quality of life, affecting populations, communities, and the relationships between organisms. One of the most unique relationships in the animal world is parasitism, which often involves tightly specialized interactions between pairs of species. Bat flies, for example, are obligate ectoparasites represented by two highly adapted dipteran families that usually parasite a single bat species or genus. Recent studies have shown that bat flies could carry pathogens such as bacteria and viruses, transmitting them among bat individuals in a colony. Because host roost characteristics can influence bat-fly parasitism, we aimed to assess whether the ecological networks between parasites and their host bats are influenced by the degree of habitat anthropization. Our hypothesis was that bat-fly interaction networks would be less specialized and more nested in highly anthropized sites. We collected bat fly individuals from bats captured at 21 sampling sites located in the Federal District of Brazil and quantified the amount of natural and anthropized area within a 3-km buffer from the sampling site. Areas consisting of agriculture, construction, mining, roads, or any man-made structure were considered anthropized. Sites presented different degrees of anthropization, with areas ranging from 100% anthropized to areas retaining full natural cover. We built bat-bat fly networks for each of the sites and excluded those with less than 0.7% of sampling completeness. We calculated key weighted structural metrics for each network, such as nestedness, specialization, and modularity. The effect of the reduction in natural cover on structural metrics was assessed through GLMMs, controlling for network size and ectoparasite diversity. Nestedness increased with the amount of anthropization, while specialization and modularity did not change and were overall high in all networks. This result suggests that anthropization may influence the assembly of bat-bat fly networks, leading to the emergence of a hierarchical assembly of interactions as parasites become less specialized and interact with a wider variety of hosts. Less specialized relationships could influence parasite fitness or even increase the likelihood of transmitting pathogens between populations of different bat species.

Ascodipteron sanmingensis sp. nov., a new bat fly (Hippoboscidae: streblid grade) from Fujian, China

The bat fly genus Ascodipteron Adensamer, 1896 currently contains 15 species, all of which occur in tropical and subtropical areas of the Eastern Hemisphere. A new species of endoparasitic bat fly, Ascodipteron sanmingensis sp. nov., was collected from the Great Himalayan Leaf-nosed Bat, Hipposideros armiger (Hodgson, 1853), during ecological studies on bats in Fujian, China. A new species, Ascodipteron sanmingensis sp. nov., is described, based on dealate neosomic females and is supported by molecular data from a 368 bp fragment of the cytochrome B (Cytb) gene. Habitus and diagnostic details, as well as the attachment sites on the host, are documented with photographs. A detailed comparison of the new species with related species is provided and the new species is accommodated in the most recent key to the world species of Ascodipteron.

Effect of seasonality and microclimate on the variation in bat-fly load (Diptera: Streblidae) in a cave bat assemblage in a dry forest

Seasonality causes fluctuations in the availability of resources, affecting the presence and abundance of animal species. These fluctuations can have an impact on parasite-host relationships, which in turn can be exacerbated by microclimatic changes to which bat-flies are exposed. We characterized the bat-fly load and evaluated the effect of seasonality on five bat species in a dry forest. We evaluated variations in microclimatic conditions inside the cave Cerro Huatulco between seasons and the response of the bat-fly load. We collected 1165 bat-fly specimens belonging to 16 species from 688 bats. The obtained results indicate that the mean abundance and infestation intensity exhibited changes between seasons in Artibeus jamaicensis, Desmodus rotundus, Glossophaga soricina, and Pteronotus parnellii. In the case of the effect of microclimate conditions, we observed that prevalence is negatively correlated with temperature in G. soricina, while mean abundance and mean infestation intensity were negatively related to temperature in A. jamaicensis and G. soricina. The present study provides significant information about host-parasite relationships in a dry forest and discusses the relevance of abiotic and biotic factors that could affect host-parasite interactions, as well as the importance of each parasite load parameter for the understanding of this interaction.

New records of bat flies (Diptera: Nycteribiidae), with an updated checklist of the nycteribiids of Russia

We assembled a checklist by documenting and curating previously published data as well as previously unpublished records of bat flies from the Russian Federation. A total of 20 bat fly species are listed, belonging to 4 genera. Basilia mongolensis nudior Hůrka, 1972 and Basilia nattereri (Kolenati, 1857) are recorded from Russia for the first time. The following new host associations are reported: Basilia mongolensis nudior ex Myotis nattereri (Kuhl), Basilia nattereri ex Eptesicus nilssonii (Keyserling & Blasius), Basilia rybini Hůrka, 1969 ex Myotis dasycneme (Boie) and Eptesicus nilssonii, and Nycteribia quasiocellata Theodor, 1966 ex Vespertilio murinus Linnaeus. We provide data on nine major Russian regions for which nycteribiid records were previously lacking.

First report of the bat fly species Basilia italica in Romania

Bat flies are haematophagous ectoparasites, highly specialised to bats and are also considered to have vectorial potential for several pathogens like Bartonella spp. or Polychromophilus spp. In Romania, past studies mostly focused on the ectoparasitic fauna of cave-dwelling bats, listing the occurrence of 10 bat fly species in the country, with only scarce information on bat flies infesting crevice-roosting bat species. Here we report the occurrence of Basilia italica, a rare nycteribiid species infesting primarily forest-dwelling bats. This is the first country-record for Romania and also represents the easternmost occurrence of this species. Further studies are needed to evaluate the vectorial potential of B. italica.

Modularity and specialization in bat–fly interaction networks are remarkably consistent across patches within urbanized landscapes and spatial scales

Patterns of specialization and the structure of interactions between bats and ectoparasitic flies have been studied mostly on non-urban environments and at local scales. Thus, how anthropogenic disturbances influence species interactions and network structure in this system remain poorly understood. Here, we investigated patterns of interaction between Phyllostomidae bats and ectoparasitic Streblidae flies, and variations in network specialization and structure across Cerrado patches within urbanized landscapes in Brazil and between local and regional scales. We found high similarity in the richness and composition of bat and fly species across communities, associated with low turnover of interactions between networks. The high specialization of bat–streblid interactions resulted in little connected and modular networks, with the emergence of modules containing subsets of species that interact exclusively or primarily with each other. Such similarities in species and interaction composition and network structure across communities and scales suggest that bat–fly interactions within Cerrado patches are little affected by the degree of human modification in the surrounding matrix. This remarkable consistency is likely promoted by specific behaviors, the tolerance of Phyllostomidae bats to surrounding urbanized landscapes as well as by the specificity of the streblid–bat interactions shaped over evolutionary time.