Project description:Leafminer insects of the genus Liriomyza are small flies whose larvae feed on the internal tissue of some of the most important crop plants for the human diet. Several of these pest species are highly uniform from the morphological point of view, meaning molecular data represents the only reliable taxonomic tool useful to define cryptic boundaries. In this study, both mitochondrial and nuclear molecular markers have been applied to investigate the population genetics of some Tunisian populations of the polyphagous species Liriomyza cicerina, one of the most important pest of chickpea cultivars in the whole Mediterranean region. Molecular data have been collected on larvae isolated from chickpea, faba bean, and lentil leaves, and used for population genetics, phylogenetics, and species delimitation analyses. Results point toward high differentiation levels between specimens collected on the three different legume crops, which, according to the species delimitation methods, are also sufficient to define incipient species differentiation and cryptic species occurrence, apparently tied up with host choice. Genetic data have also been applied for a phylogenetic comparison among Liriomyza species, further confirming their decisive role in the systematic studies of the genus.
Project description:Liriomyza trifolii is an economically-significant polyphagous pest that infests plants grown in both field and greenhouse conditions. Unfortunately, the lack of genomic resources has hindered our understanding of its ecological adaptation and invasiveness. To address this, we assembled a chromosome-level genome sequence of L. trifolii using a combination of short Illumina reads, PacBio HiFi long sequencing, and Hi-C scaffolding technology. The genome size was calculated at 122.64 Mb, the scaffold N50 value was 23.84 Mb, and 96.25% of the assembled sequences mapped to five chromosomes. BUSCO analysis showed high completeness with 95.28% gene coverage. A total of 11,883 protein-coding genes were identified along with 20.60 Mb of transposable elements. In summary, the genome of L. trifolii provides a valuable genetic resource for understanding invasive pests and developing effective management strategies.
Project description:The pea leafminer (Liriomyza huidobrensis) is a notorious pest of vegetables and ornamental plants worldwide. Despite a large number of studies on its biology and ecology, the courtship behavior and sexual communication of this species remain unclear. Here, we studied vibrational communication in the sexual interaction of the pea leafminer. On host plant leaves, females and males behaviorally displayed the bobbing-quivering alternation, which finally led to copulation. Moreover, records of laser vibrometry revealed three-signal duets underlying the behavioral alternation. Sexually mature males spontaneously emitted calls (MCs) to initiate the duets. The females rapidly responded to MCs by emitting replies (FRs) that are longer in duration. The FRs further triggered male replies (MRs) in their search for potential partners. Leafminer-produced vibrational signals convey efficient information to partners and generate pair formation on stretched substrates, such as plant leaves and nylon mesh, but cannot elicit responses on dense substrates, such as glass and plastic. Vibrational playbacks of both MCs and FRs can elicit replies in females and males, respectively. This study completely characterizes substrate-borne vibrational duets in a dipteran insect. The discovery of vibrational sex signals in the pea leafminer provides new insights for the development of novel approaches to control the pest and its relative species.
Project description:Liriomyza huidobrensis is a leafminer fly and significant horticultural pest. It is a quarantine listed species in many countries and is now present as an established pest in Australia. Liriomyza huidobrensis uses a broad range of host plants and has potential for spread into various horticultural systems and regions of Australia. Rapid in-field identification of the pest is critically needed to assist efforts to manage this pest. Morphological identification of the pest is effectively limited to specialist examinations of adult males. Generally, molecular methods such as qPCR and DNA barcoding for identification of Liriomyza species require costly laboratory-based hardware. Herein, we developed two independent and rapid LAMP assays targeted to independently inherited mitochondrial and nuclear genes. Both assays are highly sensitive and specific to L. huidobrensis. Positive signals can be detected within 10 min on laboratory and portable real-time amplification fluorometers. Further, we adapted these assays for use with colorimetric master mixes, to allow fluorometer free in-field diagnostics of L. huidobrensis. Our LAMP assays can be used for stand-alone testing of query specimens and are likely to be essential tools used for rapid identification and monitoring of L. huidobrensis.
Project description:Liriomyza trifolii is a highly-invasive leafmining insect that causes significant damage to vegetables and horticultural crops worldwide. Relatively few studies have quantified gene expression in L. trifolii using real-time quantitative PCR (RT-qPCR), which is a reliable and sensitive technique for measuring gene expression. RT-qPCR requires the selection of reference genes to normalize gene expression data and control for internal differences between samples. In this study, nine housekeeping genes from L. trifolii were selected for their suitability in normalizing gene expression using geNorm, Normfinder, BestKeeper, the ΔCt method and RefFinder. HSP21.7, which encodes heat shock protein 21.7, was used as a target gene to validate the expression of candidate reference genes. Results indicated that ACTIN and 18S were optimal for developmental stage and low temperature, TUB and 18S showed the most stable expression for sex, and GAPDH and ACTIN were the best reference genes for monitoring gene expression at high temperature. Selection and validation of appropriate reference genes are critical steps in normalizing gene expression levels, which improve the accuracy and quality of expression data. Results of this study provide vital information on reference genes and is valuable in developing a standardized RT-qPCR protocol for functional genomics research in L. trifolii.
Project description:Agricultural crops around the world are attacked by approximately 3,000-10,000 species of pest insect. There is increasing interest in resolving this problem using environmentally friendly approaches. Wolbachia (Hertig), an insect endosymbiont, can modulate host reproduction and offspring sex through cytoplasmic incompatibility (CI). The incompatible insect technique (IIT) based on CI-Wolbachia is a promising biological control method. Previous studies have reported an association between CI and Wolbachia density, which may involve a quorum sensing (QS) mechanism. In this study, we investigated the effect of manipulating QS in Wolbachia using several chemicals including 3O-C12-HSL; C2HSL; spermidine (QS inducers), 4-phenylbutanoyl; and 4-NPO (QS inhibitors) on American serpentine leafminer (Liriomyza trifolii [Burgess]), an agricultural pest. The results showed that inducing QS with 3O-C12-HSL decreased the proportion of hatched eggs and increased Wolbachia density, whereas QS inhibition with 4-phenylbutanoyl had the opposite effects. Thus, manipulating QS in Wolbachia can alter cell density and the proportion of hatched eggs in the host L. trifolii, thereby reducing the number of insect progeny. These findings provide evidence supporting the potential efficacy of the IIT based on CI-Wolbachia for the environmentally friendly control of insect pest populations.
Project description:New records are provided of the family Agromyzidae (leaf-miner flies) from Morocco. Thirty agromyzid species are newly recorded, seven of these in Agromyzinae: Agromyza (Agromyzaanthracina, A.conjuncta, A.mobilis, A.myosotidis, A.nigrescens), Hexomyza (H.simples), and Ophiomyia (O.pinguis). The other 23 new records are in Phytomyzinae: Amauromyza (Cephalomyza) karli, Calycomyzaflavomaculata, C.solidaginis, Cerodontha (Butomomyza) eucaricis, C. (Dizygomyza) luctuosa, C. (Icteromyza) geniculata, Chromatomyiacentaurii, Liriomyzaamoena, L.brassicae, L.strigata, Phytoliriomyzaarctica, P.perpusilla, P.pteridii, Phytomyzaanemones, Ph.clematidis, Ph.crassiseta, Ph.notata, Ph.plantaginis, Ph.rufipes, Ph.vitalbae, Pseudonapomyzaconfusa, Ps.palavae, and Ps.vota. The genus Calycomyza Hendel is newly reported from the country. The present study is based on recent entomological surveys and has increased the total number of agromyzid species in Morocco to 92. Information on the distribution and ecology of each species is provided.
Project description:Agromyzidae is a dipteran family that has diversified as internal plant feeders. Although most agromyzid species feed on herbaceous angiosperms, only a limited number of species has been recorded as miners of bryophytes. Extensive searches and rearing of bryophytivores in the Japanese Archipelago were made, resulting in that thallus-mining agromyzids are overwhelmingly widespread and diverse on thalloid liverworts and hornworts. By examining the morphology of adult flies, it was revealed that the agromyzid fauna comprise 39 species, of which 37 species are newly described. All the species are assigned to the genus Phytoliriomyza Hendel based on some shared morphological character states as follows: costa reaching M1; orbital setulae minute and erect (rarely proclinate); male epandrium with combs of fused tubercle-like setae and/or hypertrophied arms bearing tubercle-like setae; male distiphallus comprising a pair of stout, extended tubules; female cercus with two stout, apical, trichoid sensilla. Of the 39 agromyzid species in Japan, 36 species are associated with liverworts: 5 spp. on Marchantia (Marchantiaceae), 2 spp. on Dumortiera (Dumortieraceae), 3 spp. on Plagiochasma, 1 sp. on Asterella, 6 spp. on Reboulia (Aytoniaceae), 1 sp. on Wiesnerella (Wiesnerellaceae), 15 spp. on Conocephalum (Conocephalaceae), and 3 spp. on Riccia (Ricciaceae). Three species are associated with hornworts: 1 sp. on Folioceros (Anthocerotaceae), 1 sp. on Megaceros (Dendrocerotaceae), and 1 sp. on Notothylas,Phaeoceros (Notothyladaceae), and Anthoceros (Anthocerotaceae). The results suggest that 37 of the 39 species are host-specific at least to plant genus level, and that the inter-specific differences in male genitalia and color patterns of scutum, antenna, and maxillary palpus have contributed to reproductive isolation on the bryophytes that the flies share.
Project description:Species level identification of Agromyzidae based on morphology is often challenging due to their small size and morphological homogeneity. DNA barcoding has been used regularly to assist with the identification of economically important species of Agromyzidae, but rarely as a tool for species delineation or identification in biodiversity surveys. The main objective of this study was to investigate whether DNA barcoding and the BIN (Barcoding Index) system could assist with species identification, species delineation, male/ female association, and diversity assessment of Agromyzidae material previously determined to morphospecies from Mitaraka, French Guiana. Amplification success was low, with sequences over 400 bp recovered for only 24 (48%) of the selected specimens. Sequences assigned to 17 morphospecies formed 16 distinct branches or clusters separated by very high (minimum of 10%) sequence divergence. Following the reassessment and subsequent reassignment of one specimen, congruence between morphology and DNA barcodes was high with a single instance of two morphospecies sharing identical sequences. While DNA barcoding did not assist with identification (none of our sequences matched those of named taxa in BOLD or GenBank), it did provide support for most of our morphospecies concepts, including male/female associations. The BIN system also provided access to information about the distribution and habitat preferences of several taxa. We conclude that DNA barcoding was a useful approach to study the species diversity of our samples but that much work remains to be done before it can be used as an identification tool for the Agromyzidae fauna of Mitaraka and the rest of the Neotropical region.
Project description:Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.