Project description:BackgroundPhlebotomine sand flies are a medically important group of insects that is responsible for the transmission of leishmaniasis. Surveillance plays a major role in vector control programmes through exploring species abundance, potential entomological risk and designing appropriate control measures. In field surveillance programmes of such nature, morphological identification of vector species is of paramount importance. However, in Sri Lanka, there is no published taxonomic key available for the identification of leishmaniasis vectors.MethodIdentification keys for both male and females of the sand flies recorded in Sri Lanka were developed using morphological features. Main identification features were compared with the original observation of specimens collected from surveys and the use of published literature. Photographic illustrations of morphological features are included with the intention of making the keys user-friendly for non-taxonomists.ResultsA total of 22 sand fly species (Diptera: Psychodidae) of the genera Phlebotomus and Sergentomyia reported in Sri Lanka from 1910 to 2019 are included in the present work.ConclusionThis simplified key, along with photographs taken from specimens would be beneficial to the health staff, entomologists and research staff who deal with leishmaniasis control programmes and vector-related studies.
Project description:We propose a general working strategy to deal with incomplete reference libraries in the DNA barcoding identification of species. Considering that (1) queries with a large genetic distance with their best DNA barcode match are more likely to be misidentified and (2) imposing a distance threshold profitably reduces identification errors, we modelled relationships between identification performances and distance thresholds in four DNA barcode libraries of Diptera (n?=?4270), Lepidoptera (n?=?7577), Hymenoptera (n?=?2067) and Tephritidae (n?=?602 DNA barcodes). In all cases, more restrictive distance thresholds produced a gradual increase in the proportion of true negatives, a gradual decrease of false positives and more abrupt variations in the proportions of true positives and false negatives. More restrictive distance thresholds improved precision, yet negatively affected accuracy due to the higher proportions of queries discarded (viz. having a distance query-best match above the threshold). Using a simple linear regression we calculated an ad hoc distance threshold for the tephritid library producing an estimated relative identification error <0.05. According to the expectations, when we used this threshold for the identification of 188 independently collected tephritids, less than 5% of queries with a distance query-best match below the threshold were misidentified. Ad hoc thresholds can be calculated for each particular reference library of DNA barcodes and should be used as cut-off mark defining whether we can proceed identifying the query with a known estimated error probability (e.g. 5%) or whether we should discard the query and consider alternative/complementary identification methods.
Project description:BackgroundPrior to this study, 141 species of Tephritidae were known to occur in Italy.New informationItalian records of nine species of the family Tephritidae (Diptera) are provided. Five species, Eurasimonastigma (Loew, 1840), Noeetabisetosa Merz, 1992, Campiglossadoronici (Loew, 1856), Xyphosialaticauda (Meigen, 1826) and Rhagoletisberberidis Jermy, 1961 are recorded from Italy for the first time, whereas four species, Inuromaesamaura (Frauenfeld, 1857), Urophoracuspidata (Meigen, 1826), Tephritisconyzifoliae Merz, 1992 and T.mutabilis Merz, 1992, previously recorded in the Fauna Europaea database without reference to collection material, are confirmed and supplemented with host plant data and other collection data.
Project description:The fruit fly (Diptera: Tephritidae) species, Ceratitis capitata, Ceratitis cosyra, Ceratitis rosa, Ceratitis quilicii, and Bactrocera dorsalis are of economic importance in South Africa. These agricultural pests cause extensive damage to a range of commercially produced fruit, primarily for export. These pests are of phytosanitary significance, and their presence in fruit-producing regions in South Africa has led to restrictions in export trade of fresh produce. Accurate identification of these flies, particularly at immature stages intercepted in fruit consignments originating from South Africa, is essential but remains an ongoing challenge. A rapid and accurate identification assay to differentiate these five species is needed for inspection and pest surveillance. High throughput sequencing data were generated for each of the five fruit fly species, and five sets of species-specific primers were designed for use in a multiplex PCR. Each primer set amplifies an amplicon of a different size for each species allowing for accurate identification. PCR sensitivity tests demonstrate that the limit of detection for this assay is 10 ng and 4 ng of DNA when extracted from larvae and adult specimens, respectively. The assay developed can be applied in fruit inspection and survey activities within the country and at ports of entry.
Project description:A diverse orchard with fruit fly hosts may provide information about trophic relationships, including new insights into beneficial insects. We evaluated the composition of the fruit fly complex to provide information on tephritid species, parasitoids and multitrophic interactions for the southern region of Minas Gerais, Brazil. Sampling was carried out using traps and by collecting fruits from plants and/or the ground according to availability/the fruiting period. Occurrences of Anastrepha amita Zucchi and A. punctata Hendel were recorded for the first time in the state of Minas Gerais, and new trophic associations were obtained for A. bahiensis Lima, A. bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart) and Ceratitis capitata (Wiedemann). Ten tephritid species were obtained from trap sampling, with C. capitata, A. fraterculus and A. obliqua being the most abundant. Five species of fruit flies and seven species of parasitoids were obtained from fruits. The braconid Doryctobracon areolatus (Szépligeti) was the most frequently collected among the parasitoid species. Pitanga (Eugenia uniflora L.) and purple guava (Psidium myrtoides O. Berg) fruits were classified as repositories of fruit fly parasitoids.
Project description:The first checklist of the Tephritidae of Morocco, containing 59 species, is presented here. Out of 38 species collected during the present project, three (Campiglossa martii (Becker, 1908), Tephritis divisa (Rondani, 1871), and Terellia sp. near longicauda) present new records for North Africa, and ten (Carpomya incompleta (Becker, 1903), Chaetorellia conjuncta (Becker, 1913), Chetostoma curvinerve Rondani, 1856, Dacus frontalis (Becker, 1922), D. longistylus (Wiedemann, 1830), Dioxyna sororcula (Wiedemann, 1830), Ensina sonchi (Linnaeus, 1767), Myopites inulaedyssentericae Blot, 1827, M. stylatus Fabricius, 1794, and Tephritis vespertina (Loew, 1844)) are new for Morocco.
Project description:Insects tend to feed on related hosts. Coevolution tends to be dominated by interactions resulting from plant chemistry in defense strategies, and evolution of secondary metabolisms being in response to insect herbivory remains a classic explanation of coevolution. The present study examines whether evolutionary constraints existing in host associations of economically important fruit flies in the species-rich tribe Dacini (Diptera: Tephritidae) and to what extent these species have evolved specialized dietary patterns. We found a strong effect of host phylogeny on associations on the 37 fruit flies tested, although the fruit fly species feeding on ripe commercially grown fruits that lost the toxic compounds after long-term domestication are mostly polyphagous. We assessed the phylogenetic signal of host breadth across the fruit fly species, showing that the results were substantially different depending on partition levels. Further, we mapped main host family associations onto the fruit fly phylogeny and Cucurbitaceae has been inferred as the most likely ancestral host family for Dacini based on ancestral state reconstruction.
Project description:In the tephritids Ceratitis capitata and Bactrocera oleae, the gene transformer acts as the memory device for sex determination, via an auto-regulatory function; and functional Tra protein is produced only in females. This paper investigates the evolution of the gene tra, which was characterised in twelve tephritid species belonging to the less extensively analysed genus Anastrepha. Our study provided the following major conclusions. Firstly, the memory device mechanism used by this gene in sex determination in tephritids likely existed in the common ancestor of the Ceratitis, Bactrocera and Anastrepha phylogenetic lineages. This mechanism would represent the ancestral state with respect to the extant cascade seen in the more evolved Drosophila lineage. Secondly, Transformer2-specific binding intronic splicing silencer sites were found in the splicing regulatory region of transformer but not in doublesex pre-mRNAs in these tephritids. Thus, these sites probably provide the discriminating feature for the putative dual splicing activity of the Tra-Tra2 complex in tephritids. It acts as a splicing activator in dsx pre-mRNA splicing (its binding to the female-specific exon promotes the inclusion of this exon into the mature mRNA), and as a splicing inhibitor in tra pre-mRNA splicing (its binding to the male-specific exons prevents the inclusion of these exons into the mature mRNA). Further, a highly conserved region was found in the specific amino-terminal region of the tephritid Tra protein that might be involved in Tra auto-regulatory function and hence in its repressive splicing behaviour. Finally, the Tra proteins conserved the SR dipeptides, which are essential for Tra functionality.
Project description:BackgroundRapid and reliable identification of quarantine pests is essential for plant inspection services to prevent introduction of invasive species. For insects, this may be a serious problem when dealing with morphologically similar cryptic species complexes and early developmental stages that lack distinctive characters useful for taxonomic identification. DNA based barcoding could solve many of these problems. The standard barcode fragment, an approx. 650 base pairs long sequence of the 5'end of the mitochondrial cytochrome oxidase I (COI), enables differentiation of a very wide range of arthropods. However, problems remain in some taxa, such as Tephritidae, where recent genetic differentiation among some of the described species hinders accurate molecular discrimination.ResultsIn order to explore the full species discrimination potential of COI, we sequenced the barcoding region of the COI gene of a range of economically important Tephritid species and complemented these data with all GenBank and BOLD entries for the systematic group available as of January 2012. We explored the limits of species delimitation of this barcode fragment among 193 putative Tephritid species and established operational taxonomic units (OTUs), between which discrimination is reliably possible. Furthermore, to enable future development of rapid diagnostic assays based on this sequence information, we characterized all single nucleotide polymorphisms (SNPs) and established "near-minimal" sets of SNPs that differentiate among all included OTUs with at least three and four SNPs, respectively.ConclusionsWe found that although several species cannot be differentiated based on the genetic diversity observed in COI and hence form composite OTUs, 85% of all OTUs correspond to described species. Because our SNP panels are developed based on all currently available sequence information and rely on a minimal pairwise difference of three SNPs, they are highly reliable and hence represent an important resource for developing taxon-specific diagnostic assays. For selected cases, possible explanations that may cause composite OTUs are discussed.