Meredith Pounds

Monarch butterflies (Danaus plexippus) are famous for their high-altitude migrations across North America, but are now facing widespread population decline. Weather conditions throughout migration and predatory birds at roosting sites elicit the need for a rapid flight response, righting reflex, and learning ability. The decline or loss of these functions can be seen in many pollinator species after exposure to pesticides, which may be a contributing factor to the decline in monarch populations. Very little research has been conducted to determine the sublethal effects of pesticides on butterflies; as such, three pesticide classes which have shown these non-target effects on pollinator species, and which are used in foliar pesticide applications, were chosen for this study. Adult monarch butterflies were force-fed 4 solutions across the following pesticide classes: pyrethroids (bifenthrin, concentration of 0.1 ppm), diamides (chlorantraniliprole, 0.001 ppm), and neonicotinoids (clothianidin, 10ppm and imidacloprid, 0.05 ppm). Behavior was tested 2, 4, 6, and 8 days after exposure, and measured via four parameters: proboscis and wing movement over a 60 second period when held, extension of the proboscis when presented sucrose solution, and flight initiation response when dropped. The butterflies force-fed pesticide did not have significantly different behavior and decline than control butterflies over the experimental period. This data suggests that adult exposure to pesticides does not significantly impact adult monarch flight capabilities, and would not inhibit migration.