DNA barcoding of sand flies (Diptera, Psychodidae, Phlebotominae) from the western Brazilian Amazon

Hidden diversity in anthropophilic sand flies of the Monticola Series (Diptera, Psychodidae)

The Monticola series comprises two anthropophilic and widely distributed species in Brazil: Pintomyia (Pifanomyia) monticola (Costa Lima, 1932) and Pintomyia (Pifanomyia) misionensis (Castro, 1959). They mainly occur in the Atlantic Rainforest, and it is known that Pi. monticola comprises at least two well-structured genetic lineages regarding a fragment of the cytochrome c oxidase subunit I (COI) gene. Here, we aim to elucidate the taxonomic status of this group using integrative taxonomy tools. Collections were performed in nine localities of four Brazilian states, and COI fragments were sequenced and merged with publicly available data. Several single-locus species delimitation algorithms, genetic distance metrics, phylogenetic trees, and haplotype networks were used to uncover cryptic diversity and population structure within Pi. monticola and Pi. misionensis. The resulting genetic clusters were then tested for morphological differences through linear and geometric morphometry of several characters. We analyzed 152 COI sequences, comprising 48 haplotypes. The maximum intraspecific p distances were 8.21% (mean 4.17%) and 9.12% (mean 4.4%) for Pi. monticola and Pi. misionensis, respectively, while interspecific ones ranged from 10.94 to 14.09% (mean 12.33%). Phylogenetic gene trees showed well-supported clades for both species, with clear structuring patterns within them. Species-delimitation algorithms split our dataset into at least three putative species for each taxon. Moreover, population structure analysis showed a strong correlation between Atlantic Forest areas of endemism as sources of molecular variation in Pi. monticola. Morphometric analyses were significant for wing shape variation and some linear measurements (mainly of the head) when comparing specimens of different genetic clusters for both taxa. These results indicate strong genetic structuring of Monticola series species, confirmed by morphometry, indicating two possible cryptic species complexes.

Improving DNA barcoding library of armored scale insects (Hemiptera: Diaspididae) in China

DNA barcoding is used to identify cryptic species, survey environmental samples, and estimate phyletic and genetic diversity. Armored scale insects are phytophagous insects and are the most species-rich taxa in the Coccoidea superfamily. This study developed a DNA barcode library for armored scale insect species collected from southern China during 2021-2022. We sequenced a total of 239 specimens, recognized as 50 morphological species, representing two subfamilies and 21 genera. Sequencing analysis revealed that the average G + C content of the cytochrome oxidase subunit I (COI) gene sequence was very low (~18.06%) and that the average interspecific divergence was 10.07% while intraspecific divergence was 3.20%. The intraspecific divergence value was inflated by the high intraspecific divergence in ten taxa, which may indicate novel species overlooked by current taxonomic treatments. All the Automated Barcode Gap Discovery, Assemble Species by Automatic Partitioning, Taxon DNA analysis and Bayesian Poisson Tree Process methods yielded largely consistent results, indicating a robust and credible species delimitation. Based on these results, an intergeneric distance threshold of ≤ 5% was deemed appropriate for the differentiation of armored scale insect species in China. This study establishes a comprehensive barcode library for the identification of armored scale insects, future research, and application.

Molecular and morphometric study of Brazilian populations of Psychodopygus davisi

In this study, we analysed the molecular and morphometric differences of several populations of the putative sand fly vector Psychodopygus davisi (Root, 1934) (Diptera, Psychodidae, Phlebotominae) in Brazil. We amplified the 658 base pair fragments of the DNA barcoding region-cytochrome c oxidase subunit 1 (COI) gene-for 57 specimens of P. davisi and three specimens of Psychodopygus claustrei (Abonnenc, Léger & Fauran, 1979). We merged our data with public sequences of the same species available from GenBank. Then, the combined dataset-87 sequences and 20 localities-was analysed using population structure analysis and different species delimitation approaches. Geometric morphometry of wings was performed for 155 specimens of P. davisi populations from the North, Midwest and Southeast Brazilian regions, analysing the differences in centroid sizes and canonical variates. Molecular analysis indicated high intraspecific genetic distance values for P. davisi (maximum p distance = 5.52%). All algorithms identified P. davisi and P. claustrei as distinct molecular taxonomic units, despite the low interspecific distance (p distance to the nearest neighbour = 4.79%). P. davisi sequences were split into four genetic clusters by population structure analysis and at least five genetic lineages using intermediate scenarios of the species delimitation algorithms. The species validation analysis of BPP strongly supported the five-species model in our dataset. We found high genetic diversity in this taxon, which is in agreement with its wide geographic distribution in Brazil. Furthermore, the wing analysis showed that specimens from the Southeast Region of Brazil are different from those in the North and the Midwest. The evolutionary patterns of P. davisi populations in Brazil suggest the presence of candidate species, which need to be validated in future studies using a more comprehensive approach with both genomic data and morphological characters.

New sand fly (Diptera, Psychodidae) records and COI DNA barcodes in the state of Maranhão, Eastern Amazon, Brazil

The sand fly fauna and the usefulness of the DNA barcoding fragment of the cytochrome c oxidase subunit I (COI) gene were accessed in a forest fragment in the municipality of Governador Newton Bello, state of Maranhão, Brazil. We performed entomological collections in three independent campaigns in May and October 2021, and January 2023. Sand flies were morphologically-identified and then DNA barcoded. Sequences were deposited and analyzed in the BOLD System Database, and various species delimitation algorithms, to assess whether DNA sequences merge into taxonomic units in accordance with nominal species. In total, 1,524 sand flies were collected, comprising 32 nominal species. Nyssomyia antunesi was the most abundant species (31.5 %), followed by Psychodopygus davisi (27 %). We reported for the first time in the state of Maranhão, the presence of Lutzomyia evangelistai, Lutzomyia sherlocki, Pressatia equatorialis, and Psathyromyia barrettoi. We amplified and analyzed 67 COI barcodes of 23 species, which were merged with conspecific sequences extracted from GenBank. The maximum intraspecific p distances ranged from 0.0 % to 14.74 %, while the distances to the nearest neighbor varied from 1.67 % to 13.64 %. The phylogenetic gene tree and species delimitation tools clustered sequences into well-supported clades/clusters for each nominal species, except for Pressatia choti/Pr. equatorialis, which have the lowest interspecific genetic distance (1.67 %). We sequenced for the first time COI barcodes of Brumptomyia brumpti, Evandromyia monstruosa, Micropygomyia rorotaensis, Micropygomyia pilosa, Pintomyia christenseni, Pintomyia pacae, Pr. equatorialis, Pa. barrettoi, and Psathyromyia hermanlenti, which will be useful for further molecular identification and classification proposals of Neotropical species. This study updated the current list of the sand fly fauna for the state of Maranhão to 97, and demonstrated that COI barcodes are useful for specific identification.

Trichophoromyia auraensis: evidence for cryptic species and first record in the state of Maranhão, Brazil

Trichophoromyia auraensis (Mangabeira, 1942) (Diptera, Psychodidae, Phlebotominae) has a wide geographic distribution in the western region of the Amazon biome, where it is a putative Leishmania vector. Here, we reported for the first time a population of this species in the Brazilian state of Maranhão, in the eastern Amazon, from which we DNA-barcoded and compared with previously processed specimens from Acre State, in the western Amazon. For this, we analyzed the DNA barcoding fragment (658 bp) of the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear internal transcribed spacer 2 (ITS2) of Trichophoromyia species using phylogenetic gene trees, and species delimitation algorithms. The analyses of COI barcodes showed high values of genetic distance (mean K2P = 5.17) and well-supported clades/MOTUs for the eastern and western populations of T. auraensis, which may indicate a possible complex of cryptic species. The western population of this taxon merged with the close-related sand fly Trichophoromyia velezbernali Posada-López, Galvis and Galati, 2018 from Colombia, which may be associated with the recent speciation history and introgression between these populations. These evidences should be evaluated with a more comprehensive sampling in terms of analyzed populations and molecular markers.