Are neonicotinoids a threat to eastern North American fireflies?

Previous research on firefly susceptibility to commonly used insecticides is limited, especially regarding neonicotinoids, the most extensively used class of insecticides in the United States. With heavy neonicotinoid use throughout firefly habitats (agricultural, suburban, and forested areas), firefly larvae may be at high risk of exposure to neonicotinoids, possibly jeopardizing this already at-risk group of charismatic insects. To assess the sensitivity of firefly larvae to neonicotinoids, we exposed Photuris versicolor complex and Photinus pyralis larvae to multiple levels of clothianidin-contaminated soil. Both P. versicolor and P. pyralis exhibited reduced feeding, less frequent soil chamber construction, and lower survival rates at field-realistic clothianidin concentrations between 1 and 10 µg g^-1 soil. Coupled with other stressors such as light pollution and habitat loss, extensive neonicotinoid use may be contributing to firefly declines in the United States.