[Pollinator] Petrol exhaust pollution impairs honey bee learning and memory

[David Inouye]

Leonard, R. J., et al. (2019). "Petrol exhaust pollution impairs honey 
bee learning and memory." Oikos 128(2): 264-273.
     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 h, 24 h and 48 h post-training. Bees took 
significantly longer to learn polluted VOCs and forgot them faster than 
unpolluted ones. We also tested the ‘masking’ potential of pollution on 
floral VOCs. Using gas chromatography mass spectroscopy we noted 
differences in the chemical profile of polluted versus unpolluted VOCs 
and tested whether bees could recognise polluted VOCs if trained using 
unpolluted ones. For several VOCs tested, bees could distinguish between 
polluted and unpolluted VOCs. Ultimately, our results show that air 
pollution changes the recognition and retention of floral VOCs by bees 
which may consequently impact foraging efficiency.


-- 
Dr. David W. Inouye
Professor Emeritus
Department of Biology
University of Maryland
College Park, MD 20742-4415
inouye at umd.edu

Principal Investigator
Rocky Mountain Biological Laboratory
PO Box 519
Crested Butte, CO 81224