New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders

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  New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders ABSTRACT Pseudoparasitoids can lead to high mortality in spider egg sacs, and in some cases, they reduce the reproductive success of a spider female to zero. On the other hand, a species that develops within the spider's egg sac uses a limited resource derived from a single egg sac for its larval development. Therefore, the most crucial behaviour that increases the fitness of free-living pseudoparasitoid females is choosing the best host for their offspring. We analysed various points of the counter-adaptations of the spider egg sac pseudoparasitoid and spiders exhibiting active maternal care, utilising the ichneumonid  Hidryta fusiventris  (Thomson, 1873) and the wolf spider  Pardosa lugubris  (Walckenaer, 1802). We showed that the oviposition decision of  H. fusiventris  is based on the spider's egg sac size and that the fema...

Evaluation of the insecticidal activity of the spider-venom peptides Dc1a and Ta1a against economically important lepidopteran pests

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Evaluation of the insecticidal activity of the spider-venom peptides Dc1a and Ta1a against economically important lepidopteran pests

Abstract

Lepidopterans are the most economically significant crop pests. They are mainly controlled with chemical insecticides that often suffer from insect resistance and adverse effects on the environment and human health. Insect-specific spider-venom peptides are considered safer, eco-friendly alternatives to chemical insecticides, and two insecticidal spider-venom derived peptides have already been commercialised by Vestaron Corporation, while more candidates are being progressed in global discovery pipelines. This study focusses on two insecticidal spider-venom peptides—Dc1a and Ta1a— and assesses their suitability in targeting five species of lepidopteran pests by injection and oral application, using Vestaron’s commercial ω/κ-Hv1a as a reference. In addition, the potential of bacterial Bt Cry toxins in providing synergistic insecticidal activities with these spider-venom peptides is evaluated. We found that when applied by injection, all peptides caused paralysis and mortality against all tested lepidopteran species within a narrow dose range. In contrast, the differences in insecticidal activity were more pronounced when orally applied. Helicoverpa consistently was the genus most susceptible to the spider-venom peptides, independent of the route of application, which we presume being related to its particular food preferences. Furthermore, we found synergistic activities for co-application of each of the spider-venom peptides with sublethal amounts of Bt Cry toxins in H. armigera. Overall, our results indicate that Dc1a and Ta1a are suitable bioinsecticide candidates for targeting certain lepidopteran pests, with co-application of Bt Cry toxins considered a viable strategy for increasing their efficacy as foliar sprays.
Herzig, V., Wang, Y., Guo, S., & King, G. F. (2025). Evaluation of the insecticidal activity of the spider-venom peptides Dc1a and Ta1a against economically important lepidopteran pests. Toxicon, 108658. https://doi.org/10.1016/j.toxicon.2025.108658