From the Atlantic Forest to the borders of Amazonia: species richness, distribution, and host association of ectoparasitic flies (Diptera: Nycteribiidae and Streblidae) in northeastern Brazil

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.

Hershkovitzia (Diptera: Nycteribiidae): revision, phylogeny, and cophylogeny

Hershkovitzia Guimares & DAndretta, 1956 belongs to Nycteribiidae (Diptera), a family of hematophagous and obligate ectoparasites of bats. Hershkovitzia parasitize bats in the Thyropteridae family, which includes only one genus, Thyroptera Spix, 1823. Hershkovitzia species mostly have a one-to-one association pattern with their hosts, except for H. cabala Peterson & Lacey, 1985 and Hershkovitzia autinoae sp. nov., which share the same host. A review is presented of the species known to date, i.e., H. primitiva Guimares & DAndretta, 1956, H. coeca Theodor, 1967, H. inaequalis Theodor, 1967, H. cabala, and H. mariae Hrycyna, Santos, Rbelo & Graciolli, 2022, and a new species, H. autinoae sp. nov., is described herein. A parsimony analysis of Hershkovitzia was carried out based on a matrix of morphological characters. A cophylogenetic analysis of these parasites and their hosts was performed using a phylogeny of Thyroptera based on a modified version of a previously-published character matrix. As a result, both Hershkovitzia and Thyroptera are monophyletic. Hershkovitzia was divided and organized into two morphological groups based on its phylogeny. As the host of H. coeca is not known, five hypothetical coevolutionary scenarios were performed with each species of Thyroptera. For each coevolutionary scenario only one solution was generated, and all scenarios indicate that the hypothetical ancestor of Hershkovitzia emerged together with the hypothetical ancestor of Thyroptera. An identification key to Hershkovitzia species is presented together with schematic drawings of the abdomen, head, and legs of each species.

Parasitism on bats by bat flies in remnants of a humid forest enclave area in Northeastern Brazil

Flies are the main bloodsucking ectoparasites of Neotropical bats. The aim of this study was to describe the community of flies on bats from a humid forest enclave, surrounded by the semiarid landscape of the Caatinga domain, in Northeastern Brazil. In addition, we tested the influence of dry and rainy periods on the parasitological indices. Fieldwork was carried out in three anthropized remnants of a humid forest enclave in the Agreste mesoregion of Pernambuco state, Northeastern Brazil. Bats were captured monthly, from August 2018 to July 2019, and the ectoparasites were collected. Overall, 807 bats of 14 species and 11 genera of the families Phyllostomidae (13 spp.) and Vespertilionidae (1 sp.) were captured. Only four bat species had >50 individuals captured, and Carollia perspicillata was the most abundant species (259/807; 32%). Five hundred and seventy-one bat flies from 13 species (11 Streblidae and 2 Nycteribiidae) were collected, of which Trichobius joblingi was the most prevalent fly (197/571; 34.5%). Only the parasitism by T. joblingi was influenced by seasonality, with higher prevalence (P = 0.01) and intensity of infestation (P = 0.02) in the dry season. No lesions associated with parasitism were observed in any of the captured bats. Our results suggest that the bat-fly relationship can be affected in different ways by environmental variables, depending on the species involved. The results of this work contribute to the knowledge about ectoparasites of bats in the Neotropical region, with emphasis on humid forest enclaves, where studies of the host-parasite-environment relationship are scarce.

Ticket to ride: fungi from bat ectoparasites in a tropical cave and the description of two new species

Bat flies are obligate ectoparasitic dipterans that are highly specialised to bats and have apomorphic characteristics, such as absent or reduced wings, and specialised legs and claws, which contribute to their survival. They are often associated with fungi and harbour a fungal diversity that is still poorly understood. Fungi were found in association with the bat flies in a cave of the Caatinga dry forest in Brazil. In total, 43% of the captured bat flies were associated with fungi. Seventy-six flies were collected. DNA sequence analyses of 39 isolates showed that the isolates belonged to 13 species within nine genera, with 38 isolates belonging to Ascomycota and one isolate to Basidiomycota, and Aspergillus was the most frequently isolated genus. Most of the genera found have also been isolated from bat bodies and other substrates/hosts in caves in different regions of the world. Based on morphological and multi-locus phylogenetic analyses, two new species of Ascomycota were described: Allophoma brasiliensis sp. nov. and Pyrenochaetopsis cecavii sp. nov.

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.

Bat-ectoparasitic fly relationships in a seasonally dry tropical forest in Brazil

Bat ectoparasitic flies are hematophagous insects highly specialized to parasitize only bats. Knowledge about how biotic and abiotic factors can influence ecological relationships between parasites and hosts is in general incipient. Large information gaps are even worst in biodiversity-rich, but poorly sampled areas like Brazil's Caatinga, the largest tropical dry forest in South America. We used bats and their highly specialized ectoparasitic flies as a study model to clarify some aspects of this host-parasite system in this semiarid environment. We conducted fieldwork at 55 sites in the Caatinga, between April 2017 and March 2020 and collected 1300 flies (19 species) on 333 bats (15 species). Bat ectoparasitic flies were highly host-specific, had an aggregated distribution, frequently formed infracommunities with only one species, and had a male-biased sex ratio. Except for the prevalence of the streblid fly Strebla guajiro on Carollia perspicillata, which was significantly higher in the rainy season, bat flies showed no preference - expressed by frequency and intensity of infestation - for host sex, and their interspecific relationships were not mediated by rainfall. Other variables that could potentially be interfering in this host-parasite relationship deserve further attention, especially in environments such as the Caatinga where there is great seasonal variation. Furthermore, the existence of species-specific responses must be taken into account.

Host ecology moderates the specialization of Neotropical bat-fly interaction networks

The transmission of diseases through parasites is a key mechanism in the regulation of plant and animal populations in ecosystems. Therefore, it is necessary to investigate the relative effect of the variables that can shape the specificity of host-parasite interactions. Previous studies have found that specialization of antagonistic interactions between fly ectoparasites and bats changes according to forest type, host richness, and roosting ecology of bats. In this study, we tested these hypotheses using data from 48 bat communities. In general, our results support previous findings that bat-fly interactions are specialized, resulting in lower niche overlap among bat flies species. In addition, we found that the specificity of bat-fly interactions is lower in tropical mountain forests and is positively related with the richness of bat host species of each study site. Finally, there was a higher bat flies niche overlap in smaller bat-fly interaction networks recorded in bat roosts in caves. We conclude that the roosting ecology of bats could be a key factor to understand the mechanisms related to the horizontal transmission of ectoparasitic flies among bats.

Structure and composition of Nycteribiidae and Streblidae flies on bats along an environmental gradient in northeastern Brazil

Bats can be parasitized by several arthropod groups, including ectoparasitic flies. The high host specificity is a common phenomenon between flies and bats. In recent years, more efforts have been employed to understand how environmental variables can influence richness and parasitic load (PL). However, many gaps still need to be filled to better understand this issue. We analyzed the PL of flies on bats sampled in three environments with different rain volume and vegetation types to verify if PL is correlated with rainfall and if there are differences in the PL on bats within and between environments. Overall, there was no correlation between rainfall and PL in the same environment, nor a difference between the three environments. When tested separately, Seba’s short-tailed bats (Carollia perspicillata (Linnaeus, 1758)) had a difference in prevalence of flies between environments and flat-faced fruit-eating bats (Artibeus planirostris (Spix, 1823)) had a greater abundance of flies in the rainy season in a semiarid area. There was no difference in PL between male and female bats. Our results suggest that bat–fly interactions are driven by several factors, not only by the amount of rainfall or vegetation, and that different host species may respond differently with no obvious general pattern.

Infracommunities of bat flies (Diptera: Streblidae and Nycteribiidae) of bats (Mammalia: Chiroptera) in three conservation units in the State of Amapá, Brazil

Abstract: Diptera belonging to the families Nycteribiidae and Streblidae are hematophagous ectoparasites, exclusively of bats. The Amapá State is located in the North Region of Brazil. The Amapá represents one of with the lowest rates of deforestation in the country, with approximately 80% of the territory preserved. Within the State, there are conservation units, Floresta Nacional do Amapá (FNA), Parque Nacional Montanhas do Tumucumaque (PNMT) and Reserva de desenvolvimento Sustentável do Rio Iratapurú (RDSI). These areas represent priority areas for the Conservation of Amazonian Biodiversity. Recently in Amapá studied on the diversity and distribution of bats, however, there are no records of associated arthropod ectoparasites. Therefore, the objective was to describe the pattern of association of Nycteribiidae and Streblidae species on bats in three protected areas of Amapá. Bats were collected through mist nets, where each host had its body visually revised and the Diptera collected were identified through a specific bibliography. One thousand and eighty- six individuals of bats flies were identified, distributed in 52 species (Streblidae = 49 and Nycteribiidae = three). Among the three infracommunities, the PNMT infracommunities was the largest found with abundance and richness of bats flies. All species found, represent new occurrences for the Amapá, being these, 18 new records for the North Region and seven new records for Brazil.