Scaptomyza Flava Research Articles

Insights into the evolution of herbivory from a leaf-mining fly.

Herbivorous insects and their host plants comprise most known species on Earth. Illuminating how herbivory repeatedly evolved in insects from non-herbivorous lineages is critical to understanding how this biodiversity is created and maintained. We characterized the trophic niche of Scaptomyza flava, a representative of a lineage nested within the Drosophila that transitioned to herbivory ~10-15 million years ago. We used natural history studies to determine if S. flava is a true herbivore or a cryptic microbe-feeder, given that the ancestral character state for the family Drosophilidae is likely microbe-feeding. Specifically, we quantified oviposition substrate choice and larval viability across food-types, trophic-related morphological traits, and nitrogen isotope and sterol profiles across putatively herbivorous and non-herbivorous drosophilids. The results of these studies show that S. flava is an obligate herbivore of living plants. Paired with its genetic model host, Arabidopsis thaliana, S. flava is a novel and powerful system for exploring mechanisms underlying the evolution of herbivory, a complex trait that enabled the exceptional diversification of insects.

Chemical Control of the Leaf Miner Scaptomyza flava Fallen (Diptera: Drosophilidae) and Determination of Acetamipride and Abamectin Residues on Radish Plant

Scaptomyza flava (Diptera: Drosophilidae) is a serious pest that attacks Brassicaceae, causing significant production losses. The current study was carried out to evaluate the relative efficiency of deltamethrin 2.5 EC, abamectin 1.8 EC, and acetamiprid 20 SP insecticides. In addition to determining the acetamiprid 20 SP and abamectin1.8 EC residues in the leaves and roots of radish. The mortality score revealed that acetamiprid 20 SP, and abamectin 1.8 EC achieved 87.3% and 72.8% respectively after 72 hours compared to deltamethrin 2.5 EC, which scored 54.42%. The chromatogram outcomes of acetamiprid 20 SP and Abamectin1.8EC demonstrated that the acetamiprid 20 SP residues sharply decreased. They reduced from 1856.8 and 25.9 to 0 mg.L-1 in both leaves and roots respectively after ten days of application. While the Abamectin1.8 EC residue was decreasing from 954.12 to 0 mg.L-1 after ten days. Furthermore, abamectin 1.8 EC residues have not been detected in the radish roots. The overall consequence proposed that both acetamiprid 20 SP and abamectin1.8 EC are highly efficient in the controlling of Scaptomyza flava larva and there are no harmful impacts for both on the edible vegetable.

Molecular Identification of Three Species of Leaf Miners from the Order Diptera on Brassicaceae Crops in Basra Governorate

The leafminer (Order: Diptera) is an insect that can be found throughout the Middle East and many other parts of the world. It feeds on a range of plants. It was discovered on several Brassicaceae family leaves in Iraq. In this study, the leafminer samples were collected from the Agricultural Experimental Station – the University of Basrah campus. These samples were microscopically analysed and morphologically characterized to distinguish leafminer genera. Our results revealed that the Agromyzidae family included two species Liriomyza sativae, and Chromatomyia horticola. While the Drosophilidae family involved Scaptomyza flava. These three genera belong to the 420 bases pair. For both intra- and interspecific variation, the mitochondrial region’s COX area has been thoroughly investigated. The results of all these studies combine to create a sizable collection of sequencing data for the Agromyzidae and Drosophilidae families.

Scaptomyza flava (miner, imported leaf)

This datasheet on Scaptomyza flava covers Identity, Distribution, Hosts/Species Affected.

Evolution of Olfactory Receptors Tuned to Mustard Oils in Herbivorous Drosophilidae.

The diversity of herbivorous insects is attributed to their propensity to specialize on toxic plants. In an evolutionary twist, toxins betray the identity of their bearers when herbivores coopt them as cues for host-plant finding, but the evolutionary mechanisms underlying this phenomenon are poorly understood. We focused on Scaptomyza flava, an herbivorous drosophilid specialized on isothiocyanate (ITC)-producing (Brassicales) plants, and identified Or67b paralogs that were triplicated as mustard-specific herbivory evolved. Using in vivo heterologous systems for the expression of olfactory receptors, we found that S. flava Or67bs, but not the homologs from microbe-feeding relatives, responded selectively to ITCs, each paralog detecting different ITC subsets. Consistent with this, S. flava was attracted to ITCs, as was Drosophila melanogaster expressing S. flava Or67b3 in the homologous Or67b olfactory circuit. ITCs were likely coopted as olfactory attractants through gene duplication and functional specialization (neofunctionalization and subfunctionalization) in S. flava, a recently derived herbivore.

Molecular Identification of Leafmining Flies From Australia Including New Liriomyza Outbreaks.

Some leafmining fly species are pests of agricultural and ornamental plants but they also include many species with little economic importance. The taxonomy of leafmining flies is often challenging because of putative cryptic species. Following new outbreaks of Liriomyza (Diptera:Agromyzidae) in Australia, we here characterize 13 dipteran leafminer species collected from Australia based on cytochrome c oxidase subunit 1 (COI) DNA barcodes, and we compare these with overseas data. We confirm barcodes of nine species from the Agromyzidae (Liriomyza sativae, L. huidobrensis, L. trifolii, L. bryoniae, L. chinensis, L. brassicae, L. chenopodii, Phytomyza plantaginis and P. syngenesiae) and one species from the Drosophilidae (Scaptomyza flava); we describe new haplotypes for some of these species. Furthermore, we provide the first DNA barcodes for two species (Cerodontha milleri and Phytoliriomyza praecellens) from the Agromyzidae and one species (Scaptomyza australis) from the Drosophilidae. These findings provide a baseline for DNA-based identification of pest Liriomyza incursions spreading across the Australian east coast in relation to other species already present in Australia.

Pseudomonas syringae enhances herbivory by suppressing the reactive oxygen burst in Arabidopsis

Plant–herbivore interactions have evolved in the presence of plant-colonizing microbes. These microbes can have important third-party effects on herbivore ecology, as exemplified by drosophilid flies that evolved from ancestors feeding on plant-associated microbes. Leaf-mining flies in the genus Scaptomyza, which is nested within the paraphyletic genus Drosophila, show strong associations with bacteria in the genus Pseudomonas, including Pseudomonas syringae. Adult females are capable of vectoring these bacteria between plants and larvae show a preference for feeding on P. syringae-infected leaves. Here we show that Scaptomyza flava larvae can also vector P. syringae to and from feeding sites, and that they not only feed more, but also develop faster on plants previously infected with P. syringae. Our genetic and physiological data show that P. syringae enhances S. flava feeding on infected plants at least in part by suppressing anti-herbivore defenses mediated by reactive oxygen species.

Evolution of herbivory in Drosophilidae linked to loss of behaviors, antennal responses, odorant receptors, and ancestral diet

Herbivory is a key innovation in insects, yet has only evolved in one-third of living orders. The evolution of herbivory likely involves major behavioral changes mediated by remodeling of canonical chemosensory modules. Herbivorous flies in the genus Scaptomyza (Drosophilidae) are compelling species in which to study the genomic architecture linked to the transition to herbivory because they recently evolved from microbe-feeding ancestors and are closely related to Drosophila melanogaster. We found that Scaptomyza flava, a leaf-mining specialist on plants in the family (Brassicaceae), was not attracted to yeast volatiles in a four-field olfactometer assay, whereas D. melanogaster was strongly attracted to these volatiles. Yeast-associated volatiles, especially short-chain aliphatic esters, elicited strong antennal responses in D. melanogaster, but weak antennal responses in electroantennographic recordings from S. flava. We sequenced the genome of S. flava and characterized this species' odorant receptor repertoire. Orthologs of odorant receptors, which detect yeast volatiles in D. melanogaster and mediate critical host-choice behavior, were deleted or pseudogenized in the genome of S. flava. These genes were lost step-wise during the evolution of Scaptomyza. Additionally, Scaptomyza has experienced gene duplication and likely positive selection in paralogs of Or67b in D. melanogaster. Olfactory sensory neurons expressing Or67b are sensitive to green-leaf volatiles. Major trophic shifts in insects are associated with chemoreceptor gene loss as recently evolved ecologies shape sensory repertoires.

Determining the host specificity of the biological control agent Trichomalus perfectus (Hymenoptera: Pteromalidae): the importance of ecological host range

We determined the host range of the parasitoid Trichomalus perfectus (Walker), a candidate for classical biological control of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), an important pest of canola in Canada. Studies were conducted in Europe and in North America. In laboratory experiments, the levels of parasitism (acceptance) of Ceutorhynchus turbatus Schultze, C. cardariae Korotyaev, C. omissus Fall and C. querceti (Gyllenhal) by T. perfectus were not significantly different than of the target host C. obstrictus. Although C. typhae (Herbst), C. pallidactylus (Marsham), C. americanus Buchanan, C. neglectus Blatchely and Ceutorhynchus sp. nr. nodipennis were parasitised by T. perfectus, the levels of parasitism were significantly lower on these species than on C. obstrictus. Ceutorhynchus peyerimhoffi Hustache, C. erysimi (Fabricius), C. alliariae H. Brisout, C. roberti Gyllenhal, Mogulones borraginis (Fabricius), Mononychus vulpeculus (Fabricius) and the leaf-mining fly Scaptomyza flava (Fallén) were not attacked. Ecological host range surveys in Europe corroborated the prediction that T. perfectus would attack C. cardariae at similar rates to C. obstrictus. In North America, the recent discovery of T. perfectus in a C. omissus population suggests that laboratory findings predicting that C. omissus is a preferred host may be the case in the field. We found that T. perfectus attacks larvae of some Ceutorhynchus spp. feeding on Brassicaceae and does not attack species outside of that host range. Thus, the parasitoid can be defined as narrowly oligophagous. These results demonstrate the value of ecological host range studies in the area of origin to validate hypotheses generated through laboratory host range experiments.

Ecological studies of Scaptomyza flava (Fallen, 1823) (Diptera: Drosophilidae) and its parasitoids

Populations of the leafminer, Scaptomyza flava, were monitored fortnightly in turnip plantings at Pukekohe, south Auckland, for more than 2 years. The fly, and its main parasitoid, Asobara sp. (nr. persimilis) (Hymenoptera: Braconidae), were present throughout the year, with populations peaking in midsummer on spring plantings. A replicated field trial, comparing four planting dates, suggests that new leaves on young plants and on flowering stems were favoured for oviposition by the leafminer. In another experiment, young leaves of flowering Gypsophila sp. were more suitable for oviposition and larval survival than leaves of younger non-flowering plants. Measurements of the mandible and associated skeleton confirmed the existence of three leafminer larval instars. The parasitoid has a partial winter diapause. In midsummer, it achieved over 80% parasitism. A survey found Asobara parasitism of S. flava was restricted to a small area of south Auckland. These data, together with its monophagy in New Zealand and molecular analysis, indicate that it is either a species close to A. persimilis or a distinct population of that species.

Genes involved in the evolution of herbivory by a leaf-mining, Drosophilid fly.

Herbivorous insects are among the most successful radiations of life. However, we know little about the processes underpinning the evolution of herbivory. We examined the evolution of herbivory in the fly, Scaptomyza flava, whose larvae are leaf miners on species of Brassicaceae, including the widely studied reference plant, Arabidopsis thaliana (Arabidopsis). Scaptomyza flava is phylogenetically nested within the paraphyletic genus Drosophila, and the whole genome sequences available for 12 species of Drosophila facilitated phylogenetic analysis and assembly of a transcriptome for S. flava. A time-calibrated phylogeny indicated that leaf mining in Scaptomyza evolved between 6 and 16 million years ago. Feeding assays showed that biosynthesis of glucosinolates, the major class of antiherbivore chemical defense compounds in mustard leaves, was upregulated by S. flava larval feeding. The presence of glucosinolates in wild-type (WT) Arabidopsis plants reduced S. flava larval weight gain and increased egg–adult development time relative to flies reared in glucosinolate knockout (GKO) plants. An analysis of gene expression differences in 5-day-old larvae reared on WT versus GKO plants showed a total of 341 transcripts that were differentially regulated by glucosinolate uptake in larval S. flava. Of these, approximately a third corresponded to homologs of Drosophila melanogaster genes associated with starvation, dietary toxin-, heat-, oxidation-, and aging-related stress. The upregulated transcripts exhibited elevated rates of protein evolution compared with unregulated transcripts. The remaining differentially regulated transcripts also contained a higher proportion of novel genes than the unregulated transcripts. Thus, the transition to herbivory in Scaptomyza appears to be coupled with the evolution of novel genes and the co-option of conserved stress-related genes.

A genomically tractable and ecologically relevant model herbivore for a model plant: new insights into the mechanisms of insect–plant interactions and evolution

AbstractThe availability of model microbial pathogens and plants has been key to characterizing resistance and virulence pathways and to shedding light on the mechanisms of host–parasite interactions and co‐evolution (e.g. Allen et al. 2004, Science306, 1957–1960; Bergelson et al. 2001, Science292, 2281–2285). However, the absence of genetically tractable arthropod parasites of model plants has impeded so far our ability to gain better insights into the mechanisms, evolution and ecological consequences of plant–herbivore interactions. In this issue of Molecular Ecology, Whiteman et al. (2011) highlight fascinating features of a drosophilid fly, Scaptomyza flava, that feeds on the model plant Arabidopsis thaliana. They explore the potential of this system for studying insect–plant interactions with a clever mix of phenotypic and genetic experiments providing a comprehensive and persuasive argument for the validity of this model system. This study sets the ground for key developments in the unravelling of mechanisms involved in (i) plant–insect interactions and co‐evolution, and (ii) transition to herbivory in arthropods and evolution of endophagous lifestyles.

Introducing <i>Asobara persimilis</i> for control of <i>Scaptomyza flava</i> in South Island brassica crops

Scaptomyza flava (Diptera Drosophilidae) known as European leaf miner has recently been identified as the pest species causing major damage to seed and other brassica crops grown in the South Island This pest is particularly damaging to hybrid Asian brassica seed crops but is also a major pest of seedlings of radish turnip and broccoli plants A larval/pupal parasitoid Asobara persimilis (Hymenoptera Braconidae) is an effective natural enemy of S flava at Pukekohe at certain times of the year A project funded by MAF Sustainable Farming Fund involves massrearing the parasitoids in Auckland and releasing them in unsprayed brassica crops in Canterbury and North Otago A total of 6550 pupae and 760 emerged adults were released over fortnightly periods at 46 sites from October 2010 to April 2011 The pupae included about 80 parasitised pupae and 20 that were unparasitised as a source of hosts for emerging parasitoids Overwintering surveys and further releases are planned for 2011/12 to try and establish this natural enemy as part of the ongoing development of IPM tools for seed forage and vegetable brassica crops grown in the South Island

Mining the plant-herbivore interface with a leafmining Drosophila of Arabidopsis.

Experimental infections of Arabidopsis thaliana (Arabidopsis) with genomically characterized plant pathogens such as Pseudomonas syringae have facilitated the dissection of canonical eukaryotic defence pathways and parasite virulence factors. Plants are also attacked by herbivorous insects, and the development of an ecologically relevant genetic model herbivore that feeds on Arabidopsis will enable the parallel dissection of host defence and reciprocal resistance pathways such as those involved in xenobiotic metabolism. An ideal candidate is Scaptomyza flava, a drosophilid fly whose leafmining larvae are true herbivores that can be found in nature feeding on Arabidopsis and other crucifers. Here, we describe the life cycle of S.flava on Arabidopsis and use multiple approaches to characterize the response of Arabidopsis to S.flava attack. Oviposition choice tests and growth performance assays on different Arabidopsis ecotypes, defence-related mutants, and hormone and chitin-treated plants revealed significant differences in host preference and variation in larval performance across Arabidopsis accessions. The jasmonate and glucosinolate pathways in Arabidopsis are important in mediating quantitative resistance against S.flava, and priming with jasmonate or chitin resulted in increased resistance. Expression of xenobiotic detoxification genes was reduced in S.flava larvae reared on Arabidopsis jasmonate signalling mutants and increased in plants pretreated with chitin. These results and future research directions are discussed in the context of developing a genetic model system to analyse insect-plant interactions.

Mating behaviour of the European leafminer <i>Scaptomyza flava</i> (Diptera Drosophilidae)

European leafminer Scaptomyza flava (Falln) is an important pest of brassicas peas and gypsophila in New Zealand This study examined the mating behaviour of this species for the first time under laboratory conditions Males were the active sex in the entire mating behavioural sequence involving approaching courting and mounting females and copulation Copulation lasted for about 20 min There was no significant difference in pre courtship courtship and mating durations between virgin and mated males However mated males were significantly more likely to perform courtship and to achieve mating than virgin ones It is suggested that males learn from mating experience which helps them achieve higher mating success Both virgin and mated males tended to disrupt mating couples but could not separate them

Effects of an herbivore-induced plant volatile on arthropods from three trophic levels in brassicas

Synthetic herbivore-induced plant volatiles (HIPVs) attract arthropod natural enemies showing potential for enhancing biological control. However, HIPVs can also affect the behavior of arthropod herbivores and possibly higher-order natural enemies, potentially complicating the use of HIPVs in biological control. The aim of our work is to understand the effects of one HIPV on the abundance of arthropods at three trophic levels. Of particular interest are effects on herbivores and enemies of natural enemies. A field experiment was carried out in turnip Brassica rapa L. (Brassicaceae) (cv. Green Globe). A randomized block design was used with a treatment of synthetic methyl salicylate (MeSA), and a control consisting of the crop alone. Yellow sticky traps were used for sampling aerial brassica pests, their natural enemies and fourth trophic-level natural enemies within the crop. Our results showed that the abundance of the diamondback moth parasitoid, Diadegma semiclausum Hellén (Hymenoptera: Ichneumonidae), the brassica leafmining pest Scaptomyza flava Fallén (Diptera: Drosophilidae), and the lacewing parasitoid, Anacharis zealandica Ashmead (Hymenoptera: Figitidae), increased significantly in the MeSA-treatment compared with the controls. Significantly more D. semiclausum females were attracted to MeSA than were males. However, it still remains unclear whether it is MeSA and/or volatiles produced by induced host plants that are attractive to the arthropods. These results are highly relevant to potential future application of HIPVs in pest management, as the attraction of arthropods within ‘untargeted’ trophic-levels may disrupt trophic cascades and challenges the ideas that the deployment of synthetic HIPVs in pest management may enhance biological control.

Evaluating the impact of insecticides on Scaptomyza flava and its parasitoid, Asobara persimilis

The leaf miner, Scaptomyza flava (Diptera: Drosophilidae), causes commercial losses to brassica crops, particularly in unsprayed Asian brassicas such as ‘Joi Choi’, ‘Pak Choi Sum’, and Chinese cabbage. The objective of this study was to assess the susceptibility of a larval/pupal parasitoid, Asobara persimilis (Hymenoptera: Braconidae), of this pest to insecticides registered for use on brassicas and to an insecticide, abamectin, used to control agromyzid leaf miners overseas, as a contribution to the development of an integrated pest management programme. Adults of A. persimilis were exposed to leaf discs dipped in solutions of field rates of abamectin and 13 insecticides registered for use on vegetable brassicas. Mortality after 24 h varied from 0% to 100%. In four replicated field trials in Pukekohe (South Auckland, New Zealand), Asian brassicas ‘Joi Choi’, ‘Pak Choi Sum’, and Chinese cabbage were sprayed with insecticides and numbers of leaves with leaf mines and fly damage were recorded from 5 plants per plot at harvest. Fly pupae emerging from leaf mines during the 4 days after sampling were kept to assess fly and parasitoid emergence rates. All insecticides tested reduced the numbers of leaves with blotch mines, although results achieved with spinosad were inconsistent. Parasitism by A. persimilis varied from 7.6% to 82% in untreated plants. Parasitoids emerged from pupae reared from plants exposed to all insecticide treatments. Although A. persimilis can reduce populations of leaf miners in summer and prevent crop damage, insecticide applications are required in spring and early summer.

Diurnal periodicity of adult eclosion mating and oviposition of the european leafminer <i>Scaptomyza flava</i> (Falln) (Diptera Drosophilidae)

The European leafminer Scaptomyza flava is an important pest of brassicas peas and gypsophila in New Zealand The patterns of S flava adult eclosion mating and oviposition were determined in the laboratory Most adults (97) emerged in the photophase with maximum adult eclosion occurring between 2 and 3 h into the photophase Mating took place exclusively in the photophase and peaked about 30 min after lights on Both male and female S flava mated more than once Females started oviposition 3 days after emergence and the fecundity (number of eggs laid) and fertility (number of eggs hatched) peaked between 5 and 10 days after emergence The mean lifetime fecundity was 133541 eggs with the fertility rate being 57 during the 40day oviposition period

Susceptibility of <i>Scaptomyza flava</i> (Diptera Drosophilidae) to insecticides

The leaf miner Scaptomyza flava (Diptera Drosophilidae) can damage Asian brassicas Methods of control are required that are compatible with biological control of the lepidopteran pests that also damage this crop Laboratory bioassays compared the susceptibility of adult flies and first instar larvae in leaf mines to 12 insecticides registered for use on brassicas and the insecticide abamectin The efficacy of seven insecticides were compared in two field trials with Joi Choi and Pak Choi and the survival of a larval/pupal parasitoid Asobara persimilis (Hymenoptera Braconidae) was assessed Adult and larval flies were susceptible to nine insecticides In the field trials abamectin deltamethrin endosulfan and fipronil gave good control of fly larvae Parasitoids emerged in treatments where fly larvae survived to pupate ie abamectin endosulfan maldison spinosad and indoxacarb

Species composition and population dynamics of leafmining flies and their parasitoids in Victoria

Abstract Mined leaves were sampled from unsprayed sites in Victoria to record the range of leafminers and their parasitoids. Three agromyzid leafminers, Liriomyza brassicae (Riley), Liriomyza chenopodii (Watt) and Chromatomyia syngenesiae Hardy, and one drosophilid leafminer, Scaptomyza flava (Fallén), were collected, along with 15 parasitoids, mainly Eulophidae. The most common parasitoids were Hemiptarsenus varicornis (Girault) (42.5%), Diglyphus isaea (Walker), 14.6%, Closterocerus mirabilis Edwards & La Salle (10.5%), and Opius cinerariae Fisher (8.5%). Most parasitoids were collected from two or more leafminer hosts. Weekly collections from Chinese cabbage (Brassica rapa var. pekinensis) infested with L. brassicae and S. flava, and beetroot (Beta vulgaris var. crassa) infested with L. chenopodii were made over two seasons at Knoxfield, Victoria to assess the relative impact of these parasitoids on agromyzid fly populations in crops. A further two parasitoid species were identified at low densities. Hemiptarsenus varicornis and D. isaea were the most numerous parasitoids collected in both crops. A different sampling method in the second year showed that O. cinerariae made up 25% of the sample from Chinese cabbage and was probably more common than estimated in the first season. Control exerted by local parasitoids was high, with 100% control of L. chenopodii reached in beets within 1–3 weeks of mines appearing and 100% control of L. brassicae within 6 weeks.