We investigated whether small RNA (sRNA) sequenced from field-collected mosquitoes and chironomids (Diptera) can be used as a proxy signature of viral prevalence within a range of species and viral groups, using sRNAs sequenced from wild-caught specimens, to inform total RNA deep sequencing of samples of particular interest. Using this strategy, we sequenced from adult Anopheles maculipennis s.l. mosquitoes the apparently nearly complete genome of one previously undescribed virus related to chronic bee paralysis virus, and, from a pool of Ochlerotatus caspius and Oc. detritus mosquitoes, a nearly complete entomobirnavirus genome. We also reconstructed long sequences (1503-6557 nt) related to at least nine other viruses. Crucially, several of the sequences detected were reconstructed from host organisms highly divergent from those in which related viruses have been previously isolated or discovered. It is clear that viral transmission and maintenance cycles in nature are likely to be significantly more complex and taxonomically diverse than previously expected.
This study provides the first integrated morphological and molecular characterization of Anopheles barbirostris van der Wulp, the nominotypical member of the Barbirostris Complex of malaria vectors in the Oriental Region, and An. vanderwulpisp.n., a sibling species of the complex found in sympatry with An. barbirostris in the vicinity of its type locality in eastern Java, Indonesia. The adult, larval and pupal stages of An. barbirostris are described and compared with those of An. vanderwulpi. The two species, however, are essentially isomorphic. The genetic identity of An. barbirostris s.s. is based on a diagnostic cytochrome oxidase I gene sequence to ensure stable use of the specific name for the prevalent concept of the species. The genetic identity of the new species is also established. Diagnostic DNA sequences for these species serve as a foundation for further taxonomic studies, and for investigations into their roles in the transmission of malaria and filariasis. The discussion includes a brief review of Anopheles classification and species complexes.
Aim The environmental effect of Pleistocene climatic change in the IndoOriental region has resulted in allopatric fragmentation and the generation of diversity in forest-associated species. The aim of this study was to determine the extent to which Pleistocene climatic change has resulted in the fragmentation and speciation of an open-habitat-adapted mosquito, Anopheles vagus s.l., across its range.Location Anopheles vagus s.l. was sampled across the Indo-Oriental region.Methods We generated 116 mitochondrial cytochrome c oxidase subunit I (COI) and 121 nuclear internal transcribed spacer 2 (ITS2) DNA sequences from 18 populations. Relationships between mitochondrial haplotypes were reconstructed using minimum spanning networks, and population structure was examined using analyses of molecular variance. The population history, including lineage divergence times, population expansion and gene flow, was inferred using beast and the isolation with migration (IM) model. ResultsThere was no evidence to support the presence of the endemic Philippines species, A. limosus; instead, Philippine populations were closely related to, and derived from, A. vagus on the eastern Southeast Asian mainland. The most distinct populations were those from Java and East Timor, which differed from all other populations by all individuals having a 4-bp insertion in the ITS2 sequence. The corresponding mitochondrial haplotypes had an estimated divergence time of 2.6 Ma [95% confidence interval (CI) 1.9-3.6 Ma]. Haplotype networks and analysis of molecular variance for COI supported western (Sri Lanka, India and Myanmar) and eastern (Thailand, Singapore, Cambodia, Vietnam and the Philippines) population groupings. This grouping structure results from the divergence of an eastern and a western mitochondrial lineage, estimated to have occurred 0.37 Ma (95% CI 0.26-0.55 Ma). Subsequent migration from the east to the west (0.16 Ma) is inferred to have created an admixture zone in Myanmar and Thailand.Main conclusions With the possible exception of populations from Java and East Timor, A. vagus appears to be one widespread genetically diverse taxon across its extensive range. The abundance of grassland during long interglacial periods may have facilitated population connectivity and range expansion across the Oriental and western Australasian regions.
Introduced species represent a threat to native wildlife worldwide, due to predation, competition, and disease transmission. Concurrent introduction of parasites may also add a new dimension of competition, i.e. parasite-mediated competition, through spillover and spillback dynamics. Urban areas are major hotspots of introduced species, but little is known about the effects of urban habitat structure on the parasite load and diversity of introduced species. Here, we investigated such environmental effects on the ectoparasite load, richness, and occurrence of spillback in two widespread invasive parakeets, Psittacula krameri and Myiopsitta monachus, in the metropolitan area of Rome, central Italy. We tested 231 parakeets and found that in both species parasite load was positively influenced by host abundance at local scale, while environmental features such as the amount of natural or urban habitats, as well as richness of native birds, influenced parasite occurrence, load, and richness differently in the two host species. Therefore, we highlight the importance of host population density and habitat composition in shaping the role of introduced parakeets in the spread of both native and introduced parasites, recommending the monitoring of urban populations of birds and their parasites to assess and manage the potential occurrence of parasite-mediated competition dynamics as well as potential spread of vector-borne diseases.
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