Virome characterization and identification of a putative parvovirus and poxvirus in bat ectoparasites of Yunnan Province, China

Ectoparasites found on bats are known to contain important microbes. However, the viruses hosted by these obligate parasites are understudied. This has led to the near oversight of the potential role of these ectoparasites in virus maintenance and transmission from bats to other interacting species and the environment. Here, we sampled bat ectoparasites parasitizing a diverse selection of bat species in the families Rhinolophidae, Vespertilionidae, Megadermatidae, Hipposideridae and Pteropodidae in Yunnan Province, China. We show that the ectoparasite prevalence was generally higher in male compared to female bats. Most ectoparasites were found to fall within the Nycteribiidae, Spinturnicidae and Streblidae bat ectoparasite families. We subsequently applied a non-biased sequencing of libraries prepared from the pooled ectoparasites, followed by an in-silico virus-centric analysis of the resultant reads. We show that ectoparasites hosted by the sampled families of bats are found to carry, in addition to a diverse set of phages, vertebrate and insect viruses in the families Aliusviridae, Ascoviridae, Chuviridae, Circoviridae, Flaviviridae, Hepadnaviridae, Hepeviridae, Herpesviridae, Iridoviridae, Marseilleviridae, Nairoviridae, Orthomyxoviridae, Parvoviridae, Poxviridae, Reoviridae, Retroviridae, and Rhabdoviridae. We further report a partial Parvovirus VP1/VP2 gene and partial Poxvirus ubiquitin-like gene predicted by two independent next generation sequencing data analysis pipelines. This study describes the natural virome of bat ectoparasites, providing a platform for understanding the role these ectoparasites play in the maintenance and spread of viruses to other animals.

Exploring the relationship between bats (Mammalia, Chiroptera) and ectoparasitic flies (Diptera, Hippoboscoidea) of the Orinoquia Region in South America

Bat flies (Nycteribiidae and Streblidae) have been used to study co-evolutionary patterns between ectoparasites and bats. In the world, Nycteribiidae and Streblidae are represented by approximately 276 and 237 species, respectively. In regions such as the Orinoquia located in the north of South America (Colombia and Venezuela), the richness of bats is high (more than 100 documented species), but studies on Nycteribiidae and Streblidae are scarce and discontinuous. To contribute to the knowledge of ectoparasitic flies in the Orinoquia, records of flies and their interactions with bats were reviewed, including new records and associations using interaction networks. We documented 124 species of Streblidae and only 12 of Nycteribiidae for the Orinoquia in approximately 102 bat species reported in Colombia and Venezuela. New records for six species of bat flies in Colombia were found (Mastopteraguimaraesi, Noctiliostreblamaai, Paradyschiriaparvuloides, Trichobiusjubatus, Trichobiusparasiticus, and Basiliaferrisi) associated with six species of bats (Cynomopsplanirostris, Desmodusrotundus, Myotishandleyi, Molossusrufus, Noctilioalbiventris, and Phyllostomushastatus). The bat-ectoparasite interaction networks in the Orinoquia revealed a pattern of antagonistic relationships, with high specialization, modularity, and low connectivity and nesting. The identified networks are between bat fly species belonging to different ecomorphological groups with unique host species. This supports the idea of ecological niche partitioning among ectoparasitic bat flies and hosts. Our study expanded the knowledge of the distribution of some fly species and the associations with bat hosts in Colombia, by presenting morphological descriptions and new observations, which are key to understanding the ecology, diversity, and distribution of these species.

Complete mitogenome of Nycteribia allotopa Speiser, 1901 (Diptera, Hippoboscoidea, Nycteribiidae) and comparative analysis of mitochondrial genomes of Nycteribiidae

In recent years, the global pandemic of bat-associated pathogens has led to increasing attention on bat ectoparasites. Numerous studies have identified human-associated pathogens in Nycteribiidae, indicating their potential as vectors. In this study, the first complete sequencing of the mitochondrial genome of Nycteribia allotopa Speiser, 1901 was sequenced and analyzed. We also compared the mitochondrial sequences of N. allotopa with those available in the database for other Nycteribiidae species. The complete mitochondrial genome of N. allotopa was found to be 15,161 bp in size with an A + T content of 82.49%. Nucleotide polymorphism analysis of 13 protein-coding genes from five species of Nycteribiidae showed that nad6 exhibited the most significant variation, while cox1 was the most conserved. Furthermore, selection pressure analysis revealed cox1 to exhibit the strongest purifying selection, while atp8, nad2, nad4L, and nad5 showed slightly looser purifying selection. Pairwise genetic distances indicated that cox1 and cox2 were evolving comparatively slowly, whereas atp8, nad2, and nad6 were evolving comparatively quickly. Phylogenetic trees constructed using Bayesian inference and maximum likelihood methods demonstrated that all four families within the superfamily Hippoboscoidea clustered into one branch each, indicating their monophyly. N. allotopa was found to be most closely related to the same genus N. parvula. This study significantly enriches the molecular database for Nycteribiidae and provides invaluable reference data for future species identification, phylogenetic analysis, and exploration of their potential as vectors for human-associated pathogens.

Remarkably low host specificity in the bat fly Penicillidia fulvida (Diptera: Nycteribiidae) as assessed by mitochondrial COI and nuclear 28S sequence data

BACKGROUND

The recognition and delineation of morphologically indistinguishable cryptic species can have broad implications for wildlife conservation, disease ecology and accurate estimates of biodiversity. Parasites are intriguing in the study of cryptic speciation because unique evolutionary pressures and diversifying factors are generated by ecological characteristics of host-parasite relationships, including host specificity. Bat flies (Diptera: Nycteribiidae and Streblidae) are obligate, hematophagous ectoparasites of bats that generally exhibit high host specificity. One rare exception is Penicillidia fulvida (Diptera: Nycteribiidae), an African bat fly found in association with many phylogenetically distant hosts. One explanation for P. fulvida's extreme polyxeny is that it may represent a complex of host-specific yet cryptic species, an increasingly common finding in molecular genetic studies of supposed generalist parasites.

METHODS

A total of 65 P. fulvida specimens were collected at 14 localities across Kenya, from bat species representing six bat families. Mitochondrial cytochrome c oxidase subunit 1 (COI) and nuclear 28S ribosomal RNA (rRNA) sequences were obtained from 59 specimens and used to construct Bayesian and maximum likelihood phylogenies. Analysis of molecular variance was used to determine how genetic variation in P. fulvida was allocated among host taxa.

RESULTS

The 28S rRNA sequences studied were invariant within P. fulvida. Some genetic structure was present in the COI sequence data, but this could be more parsimoniously explained by geography than host family.

CONCLUSIONS

Our results support the status of P. fulvida as a rare example of a single bat fly species with primary host associations spanning multiple bat families. Gene flow among P. fulvida utilizing different host species may be promoted by polyspecific roosting behavior in bats, and host preference may also be malleable based on bat assemblages occupying shared roosts. The proclivity of generalist parasites to switch hosts makes them more likely to vector or opportunistically transmit pathogens across host species boundaries. Consequently, the presence of polyxenous bat flies is an important consideration to disease ecology as bat flies become increasingly known to be associated with bat pathogens.

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.

Co-occurrence of Ectoparasites (Insecta and Arachnida) on Bats (Chiroptera) in an Atlantic Forest Remnant, Southeastern Brazil

PURPOSE

Neotropical bats are infested by multiple ectoparasites (like bat fly and mite species) and investigations on these invertebrates on their hosts are crucial to better understand the ectoparasite-ectoparasite and ectoparasite-host associations. The goal of this study was to report ectoparasites species (bat flies and mites) on bats, emphasizing ectoparasite co-occurrences and host-ectoparasite associations. We also test if there is relationship between bat flies and mites on their hosts.

METHODS

This study occurred twice a month from September 2011 to September 2012 in an Atlantic Forest remnant in Rio de Janeiro State, Brazil. Spearman correlation was used to test relationship between bat flies and mites.

RESULTS

We found 27 species of ectoparasites on 13 species of bats. Ectoparasites belonged to the bat fly families Streblidae and Nycteribiidae, and the mite families Spinturnicidae, Macronyssidae, Sarcoptidae, and Trombiculidae. Streblid-streblid association was more frequent, but we also recorded streblid-spinturnicid, streblid-sarcoptid and spinturnicid-spinturnicid associations. The abundance of spinturnicid species was negatively related to the abundance of streblid species. We record the first occurrence of Strebla chrotopteri associated with Chrotopterus auritus, Periglischrus paracutisternus associated with Trachops cirrhosus and Basilia juquiensis associated with Myotis riparius for Rio de Janeiro State.

CONCLUSION

There were several co-occurrences between different taxa and between species of the same family. These results show the importance of the integrated taxonomic record. The negative interspecific interactions between spinturnicid and streblid may affect distributions, structuring ectoparasite communities on hosts.

Laboulbeniales (Fungi: Ascomycota) infection of bat flies (Diptera: Nycteribiidae) from Miniopterus schreibersii across Europe

BACKGROUND

Bat flies (Diptera: Nycteribiidae and Streblidae) are obligate, blood-sucking ectoparasites of bats with specialized morphology, life-cycle and ecology. Bat flies are occasionally infected by different species of Laboulbeniales (Fungi: Ascomycota), microscopic fungal ectoparasites belonging to three genera: Arthrorynchus spp. are restricted to the Eastern Hemisphere, while species of Gloeandromyces and Nycteromyces occur on Neotropical bat flies. Little is known about the distribution and host specificity of Arthrorynchus spp. on bat flies. In this study, we focused on sampling bat flies from the cave-dwelling bat species Miniopterus schreibersii. Bat and ectoparasite collection took place in Albania, Croatia, Hungary, Italy, Portugal, Slovakia, Spain and Switzerland. Flies were inspected for Laboulbeniales infections.

RESULTS

Six hundred sixty seven bat flies of five species were collected: Nycteribia latreillii, N. pedicularia, N. schmidlii, Penicillidia conspicua, and P. dufourii. Laboulbeniales infection was observed on 60 specimens (prevalence = 9%). Two Laboulbeniales species, Arthrorhynchus eucampsipodae and A. nycteribiae, were present on three bat fly species. All observations of A. eucampsipodae were on N. schmidlii, and A. nycteribiae was present on P. conspicua and P dufourii. Arthrorhynchus eucampsipodae is, for the first time, reported from Slovakia and Spain. Arthrorhynchus nycteribiae represents a new country record for Portugal and Slovakia. There were no significant differences among infection rates in different countries. Females of N. schmidlii showed a higher infection rate than males with an observable trend (P = 0.0502). No sex differences in infection rate for P. conspicua and P. dufourii were detected. Finally, thallus density was significantly lower in N. schmidlii compared to P. conspicua and P. dufourii.

CONCLUSIONS

With this study, we contribute to the knowledge of the geographical distribution and host specificity of Laboulbeniales fungi associated with ectoparasitic bat flies within Europe. We discuss parasite prevalence and host specificity in the light of our findings and the available literature. Penicillidia conspicua is unambiguously the main host species for A. nycteribiae based on our and previous findings. Differences in parasite intensity and sex-biased infections of the fungi are possible depending on the species.

Leg structure explains host site preference in bat flies (Diptera: Streblidae) parasitizing neotropical bats (Chiroptera: Phyllostomidae)

Bat flies (Streblidae) are diverse, obligate blood-feeding insects and probably the most conspicuous ectoparasites of bats. They show preferences for specific body regions on their host bat, which are reflected in behavioural characteristics. In this study, we corroborate the categorization of bat flies into three ecomorphological groups, focusing only on differences in hind leg morphology. As no detailed phylogeny of bat flies is available, it remains uncertain whether these morphological differences reflect the evolutionary history of bat flies or show convergent adaptations for the host habitat type. We show that the division of the host bat into three distinct habitats contributes to the avoidance of interspecific competition of bat fly species. Finally, we found evidence for density-dependent competition between species belonging to the same ecomorphological group.

Hidden diversity of Nycteribiidae (Diptera) bat flies from the Malagasy region and insights on host-parasite interactions

Background

We present information on Nycteribiidae flies parasitizing the bat families Pteropodidae, Miniopteridae and Vespertilionidae from the Malagasy Region, contributing insight into their diversity and host preference.

Results

Our phylogenetic analysis identified nine clusters of nycteribiid bat flies on Madagascar and the neighbouring Comoros Archipelago. Bat flies sampled from frugivorous bats of the family Pteropodidae are monoxenous: Eucampsipoda madagascariensis, E. theodori and Cyclopodia dubia appear wholly restricted to Rousettus madagascariensis, R. obliviosus and Eidolon dupreanum, respectively. Two different host preference patterns occurred in nycteribiids infecting insectivorous bats. Flies parasitizing bats of the genera Miniopterus (Miniopteridae) and Myotis (Vespertilionidae), namely Penicillidia leptothrinax, Penicillidia sp. and Nycteribia stylidiopsis, are polyxenous and showed little host preference, while those parasitizing the genera Pipistrellus and Scotophilus (both Vespertilionidae) and referable to Basilia spp., are monoxenous. Lastly, the inferred Bayesian phylogeny revealed that the genus Basilia, as currently configured, is paraphyletic.

Conclusion

This study provides new information on the differentiation of nycteribiid taxa, including undescribed species. Host preference is either strict as exemplified by flies parasitizing fruit bats, or more relaxed as found on some insectivorous bat species, possibly because of roost site sharing. Detailed taxonomic work is needed to address three undescribed nycteribiid taxa found on Pipistrellus and Scotophilus, tentatively allocated to the genus Basilia, but possibly warranting different generic allocation.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2582-x) contains supplementary material, which is available to authorized users.

Relationships among different facets of host specificity in three taxa of haematophagous ectoparasites

Host specificity is a fundamental trait of a parasite species. Recently, multiple aspects of host specificity have been recognized, but the relationships between these facets are still poorly understood. Here, we studied pairwise relationships between basic, structural, phylogenetic and geographic host specificity in three taxa of haematophagous ectoparasitic arthropods that differ in tightness of their association with the host. We asked which metrics of host specificity are correlated within each parasite taxon and whether the patterns of the association between different facets of host specificity are similar among parasite taxa. Data on bat flies were taken from published surveys across the Neotropics while data on fleas and mites parasitic on small mammals were compiled from multiple published surveys across the Palaearctic. Basic, structural, phylogenetic and geographic specificity indices were calculated for 18 bat fly species recorded on 40 host species from 15 regions, 109 flea species recorded on 120 host species from 51 regions and 34 mite species recorded on 67 host species from 28 regions. Then, we tested for the correlation between any two measures of host specificity using model II regressions. We found that structural and basic specificity, as well as structural and geographic specificity, exhibited a positive association in all three taxa. However, basic and geographic specificity, as well as basic and phylogenetic specificity, were significantly positively associated in fleas but did not correlate in bat flies or mites. In addition, we found a significant negative association between structural and phylogenetic specificity in bat flies but no association in the remaining taxa. Moreover, geographic and phylogenetic specificity were not associated in any parasite taxon. Our results suggest that different facets of host specificity were shaped differently by natural selection in different taxa.

Parasites of parasites of bats: Laboulbeniales (Fungi: Ascomycota) on bat flies (Diptera: Nycteribiidae) in central Europe

BACKGROUND

Bat flies (Streblidae and Nycteribiidae) are among the most specialized families of the order Diptera. Members of these two related families have an obligate ectoparasitic lifestyle on bats, and they are known disease vectors for their hosts. However, bat flies have their own ectoparasites: fungi of the order Laboulbeniales. In Europe, members of the Nycteribiidae are parasitized by four species belonging to the genus Arthrorhynchus. We carried out a systematic survey of the distribution and fungus-bat fly associations of the genus in central Europe (Hungary, Romania).

RESULTS

We encountered the bat fly Nycteribia pedicularia and the fungus Arthrorhynchus eucampsipodae as new country records for Hungary. The following bat-bat fly associations are for the first time reported: Nycteribia kolenatii on Miniopterus schreibersii, Myotis blythii, Myotis capaccinii and Rhinolophus ferrumequinum; Penicillidia conspicua on Myotis daubentonii; and Phthiridium biarticulatum on Myotis capaccinii. Laboulbeniales infections were found on 45 of 1,494 screened bat flies (3.0%). We report two fungal species: Arthrorhynchus eucampsipodae on Nycteribia schmidlii, and A. nycteribiae on N. schmidlii, Penicillidia conspicua, and P. dufourii. Penicillidia conspicua was infected with Laboulbeniales most frequently (25%, n = 152), followed by N. schmidlii (3.1%, n = 159) and P. dufourii (2.0%, n = 102). Laboulbeniales seem to prefer female bat fly hosts to males. We think this might be due to a combination of factors: female bat flies have a longer life span, while during pregnancy female bat flies are significantly larger than males and accumulate an excess of fat reserves. Finally, ribosomal DNA sequences for A. nycteribiae are presented.

CONCLUSIONS

We screened ectoparasitic bat flies from Hungary and Romania for the presence of ectoparasitic Laboulbeniales fungi. Arthrorhynchus eucampsipodae and A. nycteribiae were found on three species of bat flies. This study extends geographical and host ranges of both bat flies and Laboulbeniales fungi. The sequence data generated in this work contribute to molecular phylogenetic studies of the order Laboulbeniales. Our survey shows a complex network of bats, bat flies and Laboulbeniales fungi, of which the hyperparasitic fungi are rare and species-poor. Their host insects, on the other hand, are relatively abundant and diverse.