Seasonal variation and host sex affect bat-bat fly interaction networks in the Amazonian savannahs.

Bats are the second-most diverse group of mammals in the world, and bat flies are their main parasites. However, significant knowledge gaps remain regarding these antagonistic interactions, especially since diverse factors such as seasonality and host sex can affect their network structures. Here, we explore the influence of such factors by comparing species richness and composition of bat flies on host bats, as well as specialization and modularity of bat-bat fly interaction networks between seasons and adult host sexes. We captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of Amapá State, northeastern region of the Brazilian Amazon. Despite female bats being more parasitized and recording greater bat fly species richness in the wet season, neither relationship was statistically significant. The pooled network could be divided into 15 compartments with 54 links, and all subnetworks comprised >12 compartments. The total number of links ranged from 27 to 48 (for the dry and wet seasons, respectively), and female and male subnetworks had 44 and 41 links, respectively. Connectance values were very low for the pooled network and for all subnetworks. Our results revealed higher bat fly species richness and abundance in the wet season, whereas specialization and modularity were higher in the dry season. Moreover, the subnetwork for female bats displayed higher specialization and modularity than the male subnetwork. Therefore, both seasonality and host sex contribute in different ways to bat-bat fly network structure. Future studies should consider these factors when evaluating bat-bat fly interaction networks.

Bats (Mammalia, Chiroptera) and bat flies (Diptera, Streblidae) from the Cazumbá-Iracema and Chico Mendes Reserve, Western Brazilian Amazon.

Bats belong to the order Chiroptera and are composed of 18 families, 202 genera, and 1420 species. Cosmopolitans, they have a high diversity of trophic and behavioral guilds, several ecosystem services, and intraspecific associations with ectoparasites. In Brazil, 68 species of Streblidae have already been recorded, although knowledge about the bat fauna and their ectoparasites is still low. Thus, the objective was to present a list of bat species, and to relate parasites with hosts, for two extractive reserves in the state of Acre, western Brazilian Amazon. The collections took place in ten nights, five in each RESEX, both carried out in August 2019. At each point, 10 mist nets (9 m × 2.5 m) were used, remaining open for 6 h. The captured bats were stored in cotton bags and had their data collected. Subsequently, the search for ectoparasites was carried out throughout the individual's body and extracted with brushes moistened with 96% ethyl alcohol and fine-tipped tweezers. Species of flies were identified to the lowest taxonomic level through specific bibliography. Thirty-three bats from six trophic guilds and 46 ectoparasitic dipterans were sampled, all from the Streblidae family. The most abundant bat family was Phyllostomidae, a recurring result in several studies carried out in the neotropical region. This is related to the selectivity of the mist net in bat sampling, in addition to a close correlation between Phyllostomidae bats and ectoparasitic flies of the Streblidae family.

Global trends in research on the effects of climate change on Aedes aegypti: international collaboration has increased, but some critical countries lag behind.

BACKGROUND: Mosquito-borne diseases (e.g., transmitted by Aedes aegypti) affect almost 700 million people each year and result in the deaths of more than 1 million people annually. METHODS: We examined research undertaken during the period 1951-2020 on the effects of temperature and climate change on Ae. aegypti, and also considered research location and between-country collaborations. RESULTS: The frequency of publications on the effects of climate change on Ae. aegypti increased over the period examined, and this topic received more attention than the effects of temperature alone on this species. The USA, UK, Australia, Brazil, and Argentina were the dominant research hubs, while other countries fell behind with respect to number of scientific publications and/or collaborations. The occurrence of Ae. aegypti and number of related dengue cases in the latter are very high, and climate change scenarios predict changes in the range expansion and/or occurrence of this species in these countries. CONCLUSIONS: We conclude that some of the countries at risk of expanding Ae. aegypti populations have poor research networks that need to be strengthened. A number of mechanisms can be considered for the improvement of international collaboration, representativity and diversity, such as research networks, internationalization programs, and programs that enhance representativity. These types of collaboration are considered important to expand the relevant knowledge of these countries and for the development of management strategies in response to climate change scenarios.

Review of studies about bat-fly interactions inside roosts, with observations on partnership patterns for publications.

Pressures from anthropogenic disturbances have triggered a wealth of studies focusing on the assessment and mitigation of the negative impacts of these disturbances on inter and intraspecific ecological interactions, including bats and bat flies in their roosts. The heterogeneity of research methods employed for these studies and the scientific imbalance between countries may constrain advances and the consolidation of the knowledge on this subject. We reviewed the literature regarding bat and bat-ectoparasite interactions in roosts assessing global research trends and patterns of author collaborative work to be able to identify key questions for future studies and potential initiatives to improve the knowledge on this subject. Current information available has mostly come from the Americas and is predominantly focused on the recognition and description of parasite-host interactions between bats and bat flies. Our findings suggest the value of increasing collaboration for future research, as several countries with largely diverse environments and high organismal richness are disconnected from the countries that produce the most publications in this area, and/or have low records of publications. These regions are in the Global South, mostly in South American and African countries. We suggest that more collaborative networks may increase scientific production in the area, and that investing in local research development and enhancing partnerships for publications may strengthen the field. These research programs and collaborations are key for the development of conservation strategies for bats and bat flies, for their roosts, and for understanding bat and bat-ectoparasite interactions.

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.