Sex-dependent effects of biosynthesized nanoparticles on stored bean pests and their non-target parasitoid

Silica and Selenium Nanoparticles Attract or Repel Scale Insects by Altering Physicochemical Leaf Traits

“…Laboratory studies showed that an Se-enriched diet acts as antifeedant for S. exigua larvae and influences their choice of plants and feeding site [41,42]. At the same time, however, Se exerts a more pronounced negative impact on the natural enemies of herbivorous insects than on the herbivores themselves, which could be attributed to a less protected body morphology [43] or the biological transfer of Se from their herbivorous hosts [44]. In recent studies, the application of specific concentrations of Se significantly influenced plant growth (Citrus reticulata at 150 mg/L [45]) and mitigated insect pest damage to a plant (Atractylodes macrocephala (Asteraceae) [46]).…”

“…In recent studies, the application of specific concentrations of Se significantly influenced plant growth (Citrus reticulata at 150 mg/L [45]) and mitigated insect pest damage to a plant (Atractylodes macrocephala (Asteraceae) [46]). However, low concentrations of SeNPs (10-500 mg/L) can increase survival of pest insects (e.g., the azuki bean beetle, Callosobruchus chinensis, and the cowpea beetle, C. maculatus) [43,47,48], whereas higher concentrations of SeNPs or Se can inhibit the development and/or survival of both pest insects and their natural enemies (at 500-1000 mg/L, C. chinensis, C. maculatus, and the parasitoid-Anisopteromalus calandrae) [43,47,48] as well as plants such as A. macrocephala [46] and Citrus reticulata (at 200 mg/L) [45]. Therefore, the application of Se within a reasonable stoichiometric range emerges as a crucial consideration for future research.…”

Low concentrations of selenium nanoparticles enhance the performance of a generalist parasitoid and its host, with no net effect on host suppression

“…As solitary idiobiont ectoparasitoids, females typically lay one egg after paralyzing a host 28 , and the developing parasitoid larva feeds from outside of its host; additional parasitoid-induced mortality can arise via host feeding 29 , a process through which adult female A. calandrae attack and consume the hemolymph of hosts to acquire nutrients for egg maturation 29–31 . Due to the importance of A. calandrae in the control of bruchine beetles and other coleopteran pests 32–36 , it is necessary to test their compatibility with the entomotoxic NPs that have garnered recent attention—selenium nanoparticles (SeNPs), in particular 37,38 —as a possible new control strategy for these insects. Furthermore, because the risks of nano-formulated insecticides are not as well studied as those of conventional insecticides 16–18 (and more controversial 39 ), these tests on A. calandrae may serve as an indicator of their ecotoxicity, providing insight into both the specificity of SeNPs as well as their impact on the biological control subset of ecosystem services.…”

“…The entomotoxic effects of SeNPs arise through the slow release of elemental selenium, which, depending on the route of entry, may amass in the Malpighian tubules and midgut, negatively impacting the growth, development, and survival of the target insect 43–45 . While SeNPs have shown some promise as an alternative control method for bruchine beetles, including C. chinensis 37,38 , they may also harm the parasitoid A. calandrae 38 . However, there is evidence of SeNPs eliciting a hormetic response in the male hosts of A. calandrae 37 , so, considering the nonspecific mode of action of SeNPs, we hypothesize that a similar result will be observed for the parasitoid.…”