Publications by authors named "Karl Gordon"

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula.

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Forty years ago, it was proposed that gas-phase organic chemistry in the interstellar medium can be initiated by the methyl cation CH (refs. ), but so far it has not been observed outside the Solar System. Alternative routes involving processes on grain surfaces have been invoked.

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The fall armyworm (FAW) Spodoptera frugiperda is thought to have undergone a rapid 'west-to-east' spread since 2016 when it was first identified in western Africa. Between 2018 and 2020, it was recorded from South Asia (SA), Southeast Asia (SEA), East Asia (EA), and Pacific/Australia (PA). Population genomic analyses enabled the understanding of pathways, population sources, and gene flow in this notorious agricultural pest species.

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The fall armyworm (FAW; Spodoptera frugiperda) is one of the major agricultural pest insects. FAW is native to the Americas, and its invasion was first reported in West Africa in 2016. Then it quickly spread through Africa, Asia, and Oceania, becoming one of the main threats to corn production.

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Native to the Americas, the invasive Spodoptera frugiperda (fall armyworm; FAW) was reported in West Africa in 2016, followed by its chronological detection across the Old World and the hypothesis of an eastward Asia expansion. We explored population genomic signatures of American and Old World FAW and identified 12 maternal mitochondrial DNA genome lineages across the invasive range. 870 high-quality nuclear single nucleotide polymorphic DNA markers identified five distinct New World population clusters, broadly reflecting FAW native geographical ranges and the absence of host-plant preferences.

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Field evolved resistance to insecticides is one of the main challenges in pest control. The fall armyworm (FAW) is a lepidopteran pest species causing severe crop losses, especially corn. While native to the Americas, the presence of FAW was confirmed in West Africa in 2016.

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Stress is a widespread phenomenon that all organisms must endure. Common in nature is oxidative stress, which can interrupt cell homeostasis to cause cell damage and may be derived from respiration or from environmental exposure through diet. As a result of the routine exposure from respiration, many organisms can mitigate the effects of oxidative stress, but less is known about responses to oxidative stress from other sources.

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The fall armyworm (FAW), Spodoptera frugiperda, is a major pest native to the Americas that has recently invaded the Old World. Point mutations in the target-site proteins acetylcholinesterase-1 (ace-1), voltage-gated sodium channel (VGSC) and ryanodine receptor (RyR) have been identified in S. frugiperda as major resistance mechanisms to organophosphate, pyrethroid and diamide insecticides respectively.

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Hybridization between invasive and native species has raised global concern, given the dramatic increase in species range shifts and pest outbreaks due to anthropogenic dispersal. Nevertheless, secondary contact between sister lineages of local and invasive species provides a natural laboratory to understand the factors that determine introgression and the maintenance or loss of species barriers. Here, we characterize the early evolutionary outcomes following secondary contact between invasive Helicoverpa armigera and native H.

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The Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested.

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Background: A major challenge to sustainable agricultural pest control is the rapid evolution of insecticide resistance. This is caused by mechanisms that reduce insecticide efficacy. Understanding the genetic mechanisms of resistance is essential for DNA-based monitoring of resistance in field populations.

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The spread of invasive insect pests is becoming an increasing problem for agriculture globally. We discuss a number of invasive insects, already of major economic significance that have recently expanded their range to become truly global threats. These include the noctuid moths Helicoverpa and Spodoptera, whose caterpillars have long been among the worst pests in their native Old and New World habitats, respectively, and the whitefly Bemisia, a major vector of plant virus diseases.

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Five species of noctuid moths, , , , and are major agricultural pests inhabiting various and often overlapping global distributions. Visual identification of these species requires a great deal of expertise and misidentification can have repercussions for pest management and agricultural biosecurity. Here, we report on the complete mitochondrial genomes of and , , and and assembled from high-throughput sequencing data.

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Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory- and field-selected resistance to Bt toxins are similar.

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Within the mega-pest lineage of heliothine moths are a number of polyphagous, highly mobile species for which the exchange of adaptive traits through hybridization would affect their properties as pests. The recent invasion of South America by one of the most significant agricultural pests, , raises concerns for the formation of novel combinations of adaptive genes following hybridization with the closely related To investigate the propensity for hybridization within the genus , we carried out whole-genome resequencing of samples from six species, focusing in particular upon population structure and its relationship with We show that both subspecies have greater genetic diversity and effective population sizes than do the other species. We find no signals for gene flow among the six species, other than between and , with nine Brazilian individuals proving to be hybrids of those two species.

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Molecular species identification using suboptimal PCR primers can over-estimate species diversity due to coamplification of nuclear mitochondrial (NUMT) DNA/pseudogenes. For the agriculturally important whitefly Bemisia tabaci cryptic pest species complex, species identification depends primarily on characterization of the mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene. The lack of robust PCR primers for the mtDNA COI gene can undermine correct species identification which in turn compromises management strategies.

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Emergence of polyphagous herbivorous insects entails significant adaptation to recognize, detoxify and digest a variety of host-plants. Despite of its biological and practical importance - since insects eat 20% of crops - no exhaustive analysis of gene repertoires required for adaptations in generalist insect herbivores has previously been performed. The noctuid moth Spodoptera frugiperda ranks as one of the world's worst agricultural pests.

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Background: The whitefly Bemisia tabaci complex harbours over 40 cryptic species that have been placed in 11 phylogenetically distinct clades based on the molecular characterization of partial mitochondrial DNA COI (mtCOI) gene region. Four cryptic species are currently within the invasive clade, i.e.

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Article Synopsis
  • The Old World bollworm Helicoverpa armigera has been identified in Brazil, but tracing its origins and paths of entry has been challenging due to limited data.
  • Research utilized international trade data and mitochondrial DNA markers, revealing 20 genetic variations in Brazil, with some linked to Asia, Africa, and Europe.
  • The findings indicate multiple introductions of the pest, highlighting the increasing agricultural trade as a serious biosecurity threat and emphasizing the need for better pest origin identification and improved risk management strategies.
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Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M.

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Article Synopsis
  • Research shows that the size of gene families related to detoxifying toxins in insects can relate to their diet complexity and likelihood of developing resistance to insecticides.
  • A study analyzed cytochrome P450, carboxyl/cholinesterase, and glutathione S-transferase genes in 65 insect species, revealing a 2-4 fold variation in gene numbers.
  • There’s a strong link between gene numbers and feeding preferences in some insect groups like Hymenoptera, but not in others like Lepidoptera; larger gene families also tend to be associated with species that have a higher chance of insecticide resistance.
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We report the complete mitochondrial DNA genome of the soybean stem fly (SSF) Melanagromyza sojae from Brazil Santa Catarina state based on Illumina MiSeq sequence data. The estimated mitogenome is 15 475 base pairs (bp) (KT597923), with 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, and 22 tRNAs, and an estimated 579 bp AT-rich control region. Similar to other insects, the SSF mitogenome is A-T bias with 40.

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The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g.

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Galaxies observed at redshift z > 6, when the Universe was less than a billion years old, thus far very rarely show evidence of the cold dust that accompanies star formation in the local Universe, where the dust-to-gas mass ratio is around one per cent. A prototypical example is the galaxy Himiko (z = 6.6), which--a mere 840 million years after the Big Bang--is forming stars at a rate of 30-100 solar masses per year, yielding a mass assembly time of about 150 × 10(6) years.

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