Transgenerational effects of a dsRNA-based insecticide on the Colorado potato beetle

The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a notorious, global pest that can quickly develop resistance against a wide range of insecticides due to their advanced detoxification mechanisms. This ability poses significant challenges for the durability of integrated pest management and creates a need to develop new control methods. A novel form of targeted control for populations of CPB employs the exogenous application of double-stranded RNA (dsRNA) that triggers the naturally occurring RNA interference (RNAi) pathway within the beetle. Ledprona, the active ingredient in the biopesticide Calantha, targets and silences an essential gene only found in CPB. Silencing this gene reduces the subsequently translated protein's prevalence, ultimately leading to mortality.  While Calantha is a highly specific control method, there is great value in investigating the potential lingering impacts of utilizing RNAi for such an adaptable pest. Insects exhibit various stress responses that alter both their phenotype and genotype when exposed to sub-lethal doses of insecticides, which can be passed down to their offspring. Preliminary investigations establish these sub-lethal doses by assessing the no observable effect limits of Ledprona in CPB. Analyzing both the inherited phenotypic patterns and the differential expression of metabolic detoxification genes in the offspring of sub-lethally exposed parents allows for a view into how dsRNA-based control methods impact following generations through inherited adaptations. Determining these transgenerational effects offers important insight into potential resistance mechanisms, which can be employed to further understand how to best control the Colorado potato beetle.