Individual study: Escape of managed bumblebees Bombus impatiens from greenhouses reduced by a plastic covering that transmits ultraviolet light, Leamington, Ontario, Canada
Morandin L.A., Laverty T.M., Kevan P.G., Khosla S. & Shipp L. (2001) Bumble bee (Hymenoptera: Apidae) activity and loss in commercial tomato greenhouses. The Canadian Entomologist, 133, 883-893
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Prevent escape of commercial bumblebees from greenhouses
A small replicated trial in Ontario, Canada, (Morandin et al. 2001) showed that loss of bees from commercially managed colonies of the common eastern bumblebee Bombus impatiens in greenhouses was much lower under a type of plastic covering that transmitted ultraviolet light (wavelengths 300-350 nm) than under coverings that blocked this kind of light. Counts were taken in greenhouses in March, when outside temperatures are too low for bumblebees to survive. After 10 day observation periods in three greenhouses of each type of covering, colonies under the plastic transmitting UV had an average of 86 bees per colony remaining, while colonies under other types of plastic covering had an average of 36 bees per colony. The authors suggest bees escaped through open gutter vents, which they cannot see so easily when there is less contrast (in the ultraviolet part of the spectrum) between daylight and light coming through the greenhouse roof.