D3195: The presence of food on insect recovery from insecticide exposure: Biotic and abiotic factors contributing to recovery

Contact insecticides are commonly used to manage pest populations in areas with stored products where insects contact the insecticide by walking on concrete or wood surfaces after it is sprayed. Studies examining the recovery of insects after exposure to contact insecticides show a marked difference when insects are given food compared to no food. However, the physiological reasons why food increases recovery in these insects is not fully understood. Here, we perform four assays on Tribolium castaneum adults to understand how temperature, humidity, amount of food, and food quality following a three-hour exposure affects recovery. We find that knockdown of the insects occurs in as little as 1 hour, with full knockdown common after the 3-hour treatment. After 48 hours of recovery, the presence of food, regardless of the amount, resulted in 60-75% of treated adults recovering to running status at 27°C. However, without food, recovery was less than 20%. At 18° and 22°C, recovery after 48 h was 0% but rose to about 10% after 7 d at 18°C and nearly 50% at 22°C. At 32°C, recovery after 24 h was nearly 100% with food present, but near 0-5% without food. We highlight the interaction of temperature and food on recovery and demonstrate the importance of as even the smallest amount of food can promote insecticide exposure recovery. As temperatures are expected to warm in many locations due to climate change, managers must be prepared to increase sanitation efforts to maintain population control of these stored product insects.