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Physiology, Biochemistry, and Toxicology

Student Competition 10-Minute Paper

Student MUVE and PBT: Vector Biology, Physiology, and Toxicology On-Demand Presentations

2nd Place: Multigenerational insecticide exposure reduces tolerance to multiple stressors in the Colorado potato beetle, Leptinotarsa decemlineata

On-Demand

Presenting Author(s)

EB

Erika Bueno (she/her/hers)

University of Vermont
Burlington, Vermont

Co-Author(s)

Yolanda H. Chen (she/her/hers)

Professor
University of Vermont
Burlington, Vermont

In agroecosystems, insect pests are constantly under pressure from multiple sources of natural and anthropogenic stress. Exposure to multiple stressors has been demonstrated to improve insect performance, through a process known as cross-protection, where protective mechanisms in response to one stressor also provide protection against another form of stress. To address whether insecticide tolerance primes insects to become tolerant of other stressors, we examined phenotypic responses to single and combined stress exposure among insecticide-selected and insecticide-susceptible (unselected) Colorado potato beetles (CPB). Specifically, we conducted a full-factorial experiment with two temperature treatments (25 C and 40 C) crossed with two insecticide treatments (water-control and sublethal dose of imidacloprid). To get a comprehensive assessment of phenotypic impacts, we examined changes in mobility, herbivory, development, female fecundity, and mortality. Contrary to our expectations, selected beetles were more sensitive to both single and combined stress than unselected beetles, as demonstrated by reduced mobility and herbivory following stress exposure. Interestingly, developmental time and female fecundity were not significantly impacted by exposure to single and combined stress in both unselected and selected beetles. Overall, our findings demonstrate that selection towards insecticide tolerance does not result in cross-protection between elevated temperature and sublethal insecticides. We speculate that physiological trade-offs associated with resistance may negatively impact the ability of insects to tolerate multiple stressors. Taken together, our results highlight the importance of understanding the interactive effects of multiple stressors on insect performance while revealing the impacts of insecticide tolerance on stress tolerance in an economically important pest.