Petrol exhaust pollution impairs honey bee learning and memory

Volatile organic compounds (VOCs) serve as important infochemicals, mediating several ecological interactions including herbivory and pollination. Atmospheric pollutants including traffic-related air pollution may impair the detection of VOCs used by insects in insect-plant interactions. We investigated the indirect effect of petrol exhaust pollution on olfactory learning and memory (short and long term) in honey bees. Using appetitive olfactory conditioning, we trained bees to learn one of four floral VOC profiles; linalool, dipentene, myrcene and geranium. VOCs were unpolluted or polluted with exhaust collected from a petrol generator. Exhaust emissions included concentrations of CO (246.07 + 17 ppm), NO (20.50 + 6.90 ppb) and NO2 (20.93 + 0.05 ppb) consistent with those typically encountered in urban areas and near roads. Once bees had learnt the training VOC, we tested whether they could recognise that VOC 1 hour, 24 hours and 48 hours post-training. Bees took significantly longer t...