No sub-lethal toxicity to bumblebees, Bombus terrestris, exposed to Bt-corn pollen, captan and novaluron

Queenless microcolonies of Bombus terrestris were fed either mixed floral pollen, non-transgenic sweet corn pollen, transgenic Bt-sweet corn pollen, or pollen mixed with either the fungicide captan or the insect growth regulator novaluron. None of the treatments significantly affected survival of worker bees, rates at which they consumed pollen or sugar syrup, their ability to produce offspring, or the timing of events in the development of their offspring, compared with the appropriate controls. Drones from microcolonies fed 0.135 mg/kg(-1) a.i. novaluron were significantly shorter-lived than controls fed floral pollen. Drones from microcolonies fed corn pollen were significantly smaller than the controls, regardless of whether the corn pollen was transgenic or not. These pest control technologies are unlikely to affect B. terrestris bumblebees significantly in the field.