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 to adapt threatens the sustainability of integrated pest management programs and highlights the need for novel, targeted control strategies. A promising 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 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 value in investigating the potential for sublethal impacts of utilizing RNAi for such an adaptable pest. Preliminary investigations established these sublethal doses by assessing the no observable effect limits of ledprona in CPB. Exposure to sublethal doses has been associated with changes in phenotypic responses, especially in reproductive capacity. These sublethal effects raise important considerations for understanding pest performance under real-world conditions, particularly in the context of incomplete spray coverage. To assess the potential for transgenerational inheritance of these impacts, offspring of sublethally exposed beetles were monitored for changes in development, survival, and phenotype. Understanding how exposed pests and their offspring behave and perform at sublethal levels is critical for predicting real-world outcomes and refining RNAi-based pest management strategies.