The heritability, stability, and fitness costs in a Cry1Ac-resistant Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) colony (AR) were measured in the laboratory. In response to selection, heritability values for AR increased in generations 4-7 and decreased in generations 11-19. AR had significantly increased pupal mortality, a male-biased sex ratio, and lower mating success compared with the unselected parental strain (SC). AR males had significantly more mating costs compared with females. AR reared on untreated diet had significantly increased fitness costs compared with rearing on Cry1Ac treated diet. AR had significantly higher larval mortality, lower larval weight, longer larval developmental period, lower pupal weight, longer pupal duration, and higher number of morphologically abnormal adults compared with SC. Due to fitness costs after 27 generations of selection as described above, AR was crossed with a new susceptible colony (SC1), resulting in AR1. After just two generations of selection, AR1 exhibited significant fitness costs in larval mortality, pupal weight and morphologically abnormal adults compared with SC1. Cry1Ac-resistance was not stable in AR in the absence of selection. This study demonstrates that fitness costs are strongly linked with selecting for Cry1Ac resistance in H. zea in the laboratory, and fitness costs remain, and in some cases, even increase after selection pressure is removed. These results support the lack of success of selecting, and maintaining Cry1Ac-resistant populations of H. zea in the laboratory, and may help explain why field-evolved resistance has yet to be observed in this major pest of Bacillus thuringiensis cotton, Gossypium hirsutum L.
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http://dx.doi.org/10.1603/0022-0493(2008)101[1421:fcawch]2.0.co;2 | DOI Listing |
PLoS One
January 2025
Department of Feed Development, Madagascar Biodiversity Center, Antananarivo, Madagascar.
Gryllus madagascarensis (Orthoptera: Gryllidae) is a cricket species that shows promise to mitigate food insecurity and malnutrition. But whether this species will accept low- to no-cost weeds and agro by-products as feed, and how these feeds affect its performance, remains unknown. This study assessed the acceptability of 66 weed species and agro by-products (derived from a single plant species) by adult G.
View Article and Find Full Text PDFBull Math Biol
January 2025
Université Côte d'Azur, Inria, INRAE, CNRS, MACBES, Sophia Antipolis, France.
The sterile insect technique (SIT) is a biological control technique based on mass-rearing, radiation-based sterilization that can induce fitness costs, and releases of the pest species targeted for population control. Sterile matings, between females and sterilized males, can reduce the overall population growth rate and cause a fall in population density. However, a proportion of irradiated males may escape sterilization, resulting in what is called residual fertility.
View Article and Find Full Text PDFSci Rep
January 2025
Laboratory of Nutrition and Physical Activity Research (LABINAF), Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile.
Cardiorespiratory fitness is the most important variable related to health and a strong predictor of mortality. However, it is rarely used in clinics due to costs, specialized equipment, space needs, and the requirements of expert staff such as an exercise physiologist, physician, or other health professional. This work aims to validate and test the reliability of a submaximal step test to estimate VOmax of 8-to 16-year-old pediatric populations as a simple and low-cost tool for clinical practice.
View Article and Find Full Text PDFWaste Manag
December 2024
Aalborg University, Department of Chemistry and Bioscience, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark. Electronic address:
Large scale production of insect larvae is considered a sustainable way to upcycle various organic waste- and by-products into more valuable food and feed products. The sustainability of insect larvae production depends on the substrates and species being used, but comparative studies that include both growth and efficiency are lacking. Here we compare larval fitness, including survival, development time, weight, substrate conversion efficiency, substrate reduction, and metabolic parameters across different combinations of densities and waste- and by-product-based substrates on the two fly species, the house fly (Musca domestica) and the black soldier fly (Hermetia illucens).
View Article and Find Full Text PDFEcol Lett
December 2024
Groningen Institute of Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.
In socially monogamous species, sexual selection not only depends on initial mate choice but also mate switching. To date, studies lack assessment of (1) differences between passive (widowhood) and active (divorce) mate switching, (2) longer term fitness consequences (beyond the season post-divorce) and (3) how age masks reproductive costs and benefits of divorce. We investigated causes and short- and long-term consequences of mate switching and their age dependence using longitudinal data on Seychelles warblers (Acrocephalus sechellensis).
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