Biology subjects

Edison, A.

Publications and source records attributed to Edison, A..

3 recordsLinked to original sources

bioRxiv2025

Bulk segregant analysis reveals genomic regions associated with imidacloprid resistance in the Colorado potato beetle

Given the increased accessibility of genomic techniques, the speed of evolution of resistance, and the large number of genes involved in resistance, investigations into the genetic basis of resistance in more species are pertinent. Despite being an important agricultural pest, only a limited number of genetic mapping studies based on crossed populations have been performed to identify genes involved in resistance in the Colorado potato beetle (Leptinotarsa decemlineata, CPB). Here, we performed bulk segregant analysis on a mapping population generated by creating advanced intercross lines from five European strains of CPB. We identified eight peaks across chromosomes 1,8,10, and 16 involved in resistance against the neonicotinoid, imidacloprid. We identified 337 genes within these peaks and shortlisted three candidates based on gene expression and functional annotation. Among the three candidates thus identified, we found that an ABC transporter and a galactosyl transferase are expressed in relatively higher amounts in a relatively more susceptible strain than in a resistant strain. We attempted to validate the role of these two genes in insecticide resistance by knocking them down in a resistant strain using RNA interference (RNAi) and performing toxicity experiments. Surprisingly, our results showed that the activation of RNAi machinery reduced imidacloprid resistance and the effect is not specific to the tested candidate genes, which raised a concern on the suitability of using RNAi for validating insecticide resistance mechanisms in CPB.

genetics↗

bioRxiv2024

The role of evolving niche choice in herbivore adaptation to host plants

Individuals living in heterogeneous environments often choose microenvironments that provide benefits to their fitness. Theory predicts that such "niche choice" can promote rapid adaptation to novel environments and help maintain genetic diversity. An open question of large applied importance is how niche choice and niche choice evolution affect the evolution of insecticide resistance in phytophagous insects. We, therefore, developed an individual-based model based on phytophagous insects to examine the evolution of insecticide resistance and host plant choice via oviposition preferences. To find biologically realistic parameter ranges, we performed an empirical literature survey on insecticide resistance in major agricultural pests and also conducted a density-dependent survival experiment using potato beetles. We find that, in comparison to a scenario where individuals randomly oviposit eggs on toxic or non-toxic plants, the evolution of niche choice generally leads to slower evolution of resistance and facilitates the coexistence of different phenotypes. Our simulations also reveal that recombination rate and dominance effects can influence the evolution of both niche choice and resistance. Thus, this study provides new insights into the effects of niche choice on resistance evolution and highlights the need for more studies on the genetic basis of resistance and choice.

evolutionary biology↗

bioRxiv2022

Evidence of active oviposition avoidance to systemically applied imidacloprid in the Colorado Potato Beetle (Leptinotarsa decemlineata)

Agricultural pests can develop behavioral resistance to insecticides via choosing to feed or oviposit on non-toxic hosts. As young larvae have relatively low mobility, oviposition preferences from female adults may play a critical role in shaping the evolutionary trajectory of pest populations. While oviposition avoidance of toxic hosts was found in different agriculture pests, it remains unclear whether such preferences can be learned from female adults. To address this question, we investigated feeding and oviposition preferences to imidacloprid in the Colorado Potato Beetle (CPB, Leptinotarsa decemlineata), a major potato pest. We first identified two CPB strains that have different levels of resistance to imidacloprid. Then, we performed choice assays in the two strains and found that both strains did not have an innate feeding avoidance to systemically applied imidacloprid at both larval and adult stages. Further oviposition choice assays showed that the susceptible strain preferred to lay eggs on insecticide-free plants while the resistant strain did not. Analysing moving patterns of the two strains suggested that the oviposition preference is likely due to active learning by the female adults. Together, these results indicate that CPB can have active oviposition avoidance, which might have contributed to the rapid global invasion of this agricultural pest.

animal behavior and cognition↗