Background: The presence of fitness costs of resistance to Bacillus thuringiensis (Bt) insecticidal proteins in insect populations may delay or even reverse the local selection of insect resistance to Bt transgenic crops, and deserves rigorous investigation. Here we assessed the fitness costs associated with Cry1Fa resistance in two strains of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), derived from field collections in different Brazilian regions and further selected in the laboratory for high levels of resistance to Cry1Fa using leaves of TC1507 corn.
Results: Fitness components were compared using paired resistant and susceptible strains with similar genetic backgrounds and F generations from reciprocal crosses, all of them reared on non-transgenic corn leaves. No apparent life history costs in the larval stage were observed in the Bt-resistant strains. Moreover, the resistance remained stable for seven generations in the absence of selection, with no decrease in the proportion of resistant individuals. Larval respiration rates were also similar between resistant and susceptible homozygotes, and heterozygotes displayed respiration rates and demographic performance equal or superior to those of susceptible homozygotes.
Conclusion: In combination, these results indicate the lack of strong fitness costs associated with resistance to Cry1Fa in the fall armyworm strains studied. These findings suggest that Cry1Fa resistance in S. frugiperda populations is unlikely to be counterselected in Cry1Fa-free environments. © 2016 Society of Chemical Industry.
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Sci Rep
December 2024
Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
Spodoptera litura (Fabricius) is a major polyphagous pest of global relevance due to the damage it causes to various crops. Chlorpyrifos (CPF) is generally used by farmers to manage S. litura, however, its widespread use has resulted in the development of insecticide resistance.
View Article and Find Full Text PDFPlant Biol (Stuttg)
December 2024
Laboratory of Entomology, Plant Sciences, Wageningen University and Research, Wageningen, The Netherlands.
Plants can sustain various degrees of damage or compensate for tissue loss by regrowth without significant fitness costs. This tolerance to insect herbivory depends on the plant's developmental stage during which the damage is inflicted and on how much tissue is removed. Plant fitness correlates, that is, biomass and germination of seeds, were determined at different ontogenetic stages, vegetative, budding, or flowering stages of three annual brassicaceous species exposed to feeding by Pieris brassicae caterpillars at different intensities.
View Article and Find Full Text PDFPlant Cell Environ
December 2024
Department of Plant and Soil Sciences and Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky, USA.
The evolutionary arms race between plants and insects has led to key adaptive innovations that drive diversification. Alkaloids are well-documented anti-herbivory compounds in plant chemical defences, but how these specialized metabolites are allocated to cope with both biotic and abiotic stresses concomitantly is largely unknown. To examine how plants prioritize their metabolic resources responding to herbivory and cold, we integrated dietary toxicity bioassay in insects with co-expression analysis, hierarchical clustering, promoter assay, and protein-protein interaction in plants.
View Article and Find Full Text PDFFront Physiol
December 2024
Unitat de Suport a la Recerca Terres de l'Ebre, Fundació Institut Universitari d'Investigació en Atenció Primària Jordi Gol i Gurina (IDIAP JGol), Tortosa, Spain.
Introduction: Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are complex central sensitization syndromes that represent an important public health problem. Low cardiorespiratory fitness and muscle function with habitual intolerance to efforts are common characteristics of FM and CFS. This study aimed to examine the effect of a brief multicomponent intervention based on physical activity (PA), nutrition, and chronobiology on movement behaviors (PA, sedentary and sleep time), muscle strength, and cardiorespiratory capacity.
View Article and Find Full Text PDFFront Psychol
December 2024
Department of Psychology, University of Oregon, Eugene, OR, United States.
The computational modeling of category learning is typically evaluated in terms of the model's accuracy. For a model to accurately infer category membership of stimuli, it has to have sufficient representational precision. Thus, many category learning models infer category representations that guide decision-making and the model's fitness is evaluated by its ability to accurately choose.
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