Helicoverpa armigera and H. zea are amongst the most significant polyphagous pest lepidopteran species in the Old and New Worlds respectively. Separation of H. armigera and H. zea is difficult and is usually only achieved through morphological differences in the genitalia. They are capable of interbreeding to produce fertile offspring. The single species status of H. armigera has been doubted, due to its wide distribution and plant host range across the Old World. This study explores the global genetic diversity of H. armigera and its evolutionary relationship to H zea. We obtained partial (511 bp) mitochondrial DNA (mtDNA) Cytochrome Oxidase-I (COI) sequences for 249 individuals of H. armigera sampled from Australia, Burkina Faso, Uganda, China, India and Pakistan which were associated with various host plants. Single nucleotide polymorphisms (SNPs) within the partial COI gene differentiated H. armigera populations into 33 mtDNA haplotypes. Shared haplotypes between continents, low F-statistic values and low nucleotide diversity between countries (0.0017 – 0.0038) suggests high mobility in this pest. Phylogenetic analysis of four major Helicoverpa pest species indicates that H. punctigera is basal to H. assulta, which is in turn basal to H. armigera and H. zea. Samples from North and South America suggest that H. zea is also a single species across its distribution. Our data reveal short genetic distances between H. armigera and H. zea which seem to have been established via a founder event from H. armigera stock at around 1.5 million years ago. Our mitochondrial DNA sequence data supports the single species status of H. armigera across Africa, Asia and Australia. The evidence for inter-continental gene flow observed in this study is consistent with published evidence of the capacity of this species to migrate over long distances. The finding of high genetic similarity between Old World H. armigera and New World H. zea emphasises the need to consider work on both pests when building pest management strategies for either.

/pdf/mitochondrial-dna-analysis-of-field-populations-of-54jv7d1270.pdf

Mitochondrial DNA analysis of field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) and of its relationship to H. zea.

An overlooked component: (Z)-9-tetradecenal as a sex pheromone in Helicoverpa armigera

To slow the resistance evolution of the European corn borer (ECB) to Cry proteins expressed in transgenic Bacillus thuringensis (Bt) corn, the United States Environmental Protection Agency (EPA) has adopted an insect resistance management (IRM) plan that relies on a ''high dose/refuge'' strategy However, this IRM plan does not consider possible ecological differences between the two ECB pheromone races (E and Z) Using carbon isotope analysis, we found that unstructured (non-corn) refuges contribute more to E race (18%) than to Z race (4%) populations of ECB in upstate New York (USA) Furthermore, feeding on non-corn hosts is associated with decreased body mass and reduced fecundity We also show that the geographic range of E-race ECB is restricted within the range of the Z race and that E-race ECB are increasingly dominant in regions with increasing non- corn habitat While the proportion of E-race ECB developing in unstructured refuges is higher than previously assumed, low rates of unstructured refuge use by the Z race, evidence for reduced fecundity when reared on non-corn hosts, and complete sympatry within the E race range all argue against a relaxation of current IRM refuge standards in corn based on alternative-host use We also discuss implications of this research for integrated pest management in vegetables and IRM in Bt cotton

https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/09-0067.1

Managing resistance to Bt crops in a genetically variable insect herbivore, Ostrinia nubilalis

We studied the mating selection in the cotton bollworm, Helicoverpa armigera (Hubner), in relation to body size and larval diet in the laboratory. When provided with an artificial diet at larval stage, weight, body and forewing length did not affect the probability of a male/female moth being selected for mating, but the abdominal width of selected female moths was significantly wider than that of non-selected female moths. 30 female moths were dissected and number of eggs was counted after mating, and there was a correlation between the abdominal width and egg number. There was also significant difference of weight loss between selected and non-selected male/female moths after the mating. The effect of operational sex ratio on mating latency and copulation duration were tested, and the result indicated that mating latency of male selection was significantly longer than that of female selection, but the difference of copulation duration was not significant. Cotton, corn and peanut plants were provided to larvae to test the effect of larval host plant experience on mate choice. When cotton- and peanut-fed moth severed as potential partners, both female and male of cotton-fed moths significantly preferred cotton- to peanut-fed moths for mating. The possible reasons for mate preference based on larval host plant experience may account for host plants attributes on sex pheromone variation and sexual maturity. These findings may impact Bacillus thuringiensis resistance management.

Effect of body size and larval experience on mate preference in Helicoverpa armigera (Hübner) (Lep., Noctuidae)

Olfaction is primarily mediated by highly specified olfactory receptors (ORs). Here, we cloned and identified an olfactory receptor, named SlituOR1 (Genbank no. JN835269), from Spodoptera litura and found evidence that it is a candidate pheromone receptor. It exhibited male-biased expression in the antennae, where it was localized at the base of sensilla trichoidea, the antennal sensilla mainly responsive to pheromones in moths. Conserved orthologues of this receptor, found among known pheromone receptors within the Lepidoptera, and SlituOR1 were placed among a clade of candidate pheromone receptors in a phylogeny tree of insect OR gene sequences. SlituOR1 showed differential expression in S. litura populations attracted to traps baited with different ratios of the two sex pheromone components (9Z,11E)-tetradecadienyl acetate (Z9E11-14:OAc) and (9Z,12E)-tetradecadienyl acetate (Z9E12-14:OAc). Knocking down of SlituOR1 by RNA interference reduced the electroantennogram (EAG) response to Z9E11-14:OAc, and this result is consistent with the field trapping experiment. We infer that variation in transcription levels of olfactory receptors may modulate sex pheromone perception in male moths and could provide some of the flexibility required to maintain the functionality of communication with females when a population is adapting to a new niche and reproductive isolation becomes an advantage.

Molecular and functional characterization of a candidate sex pheromone receptor OR1 in Spodoptera litura.

Field trials were conducted at various locations in India to assess sex pheromone response of Helicoverpa armigera males to varying blends of its two sex pheromone components. In the pheromone septa that were used to baitthe pheromone traps varying blends were impregnated and the ratio of Z-9 : hexadecenal to Z-11: hexadecenal in them varied from 0: 100 to 15 : 85. Results indicated geographical variation in response of males to varying blends of the two sex pheromone components, suggesting male sex pheromone response polymorphism.

Variability in response of Helicoverpa armigera males from different locations in india to varying blends of female sex pheromone suggests male sex pheromone response polymorphism

The results of field survey carried out in 14 villages in Sirsa district (Haryana) indicated increasing trend in the population of Spodoptera litura (Fab.) from 1.36±0.96 ((ange 0.30–3.47) in 2004 to 2.43±2.0 (range 0030-7.35) per plant in 2005. The field experrments conducted on natural infestation of Bt and non Bt cotton hybrids revealed that the incidence of S. litura on Bt cotton initiated in 38th and 35th Meteorological Standard Week (MSW) in 2004 and 2005, respectively. The population reached maximum of 1.50 larvae per plant and 0.9 larva per plant in RCH-134 Bt and Ankur 651 Bt on 40th and 38th MSW during 2004 and 2005, respectively. The difference between the incidence of S. litura in Bt cotton (Bollgard I - Cry 1Ac) (0.25–0.28 larva per plant) and non Bt cotton (0.10–0.28 larva per plant) remained statistically non significant.

Spodoptera litura: An Emerging Pest on Bt Cotton (Cry 1Ac) under North Indian Conditions

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

D Monga

Author Tools

Chat about Author

Papers

Variability in response of Helicoverpa armigera males from different locations in india to varying blends of female sex pheromone suggests male sex pheromone response polymorphism

Spodoptera litura: An Emerging Pest on Bt Cotton (Cry 1Ac) under North Indian Conditions