Effects of ingestion of a Bacillus thuringiensis toxin and a trypsin inhibitor on honey bee flight activity and longevity

To assess potential impacts of transgenic pest-resistant plants, newly-emerged adult honey bees from ten colonies were tagged, placed in cages at 33 oC, and fed with 625 $\mu$g/g Cry1Ba Bacillus thuringiensis (Bt) toxin or 2.5 mg/g aprotinin proteinase inhibitor in pollen-food (equivalent to 0.25% or 1% of total soluble protein). Control bees were given similar food without additive. All foods were consumed at similar rates. After seven days, all bees were returned to their hives. Subsequent observations showed that Cry1Ba-fed bees did not differ significantly from control bees in the timing of their first flight, the period during which flights took place or in estimated longevity. However, aprotinin-fed bees began to fly and also died about three days sooner than Cry1Ba-fed or control bees. Their flight periods were similar to those of the other bees. The effects of transgenic aprotinin-plants on honey bees will thus depend on gene expression levels in pollen

Effects of ingestion of a biotin-binding protein on adult and larval honey bees

The insecticidal properties of biotin-binding proteins (BBPs) have recently been exploited in transgenic plants. As BBPs have a broad spectrum of insect toxicity, their potential impacts on non-target insects such as honey bees need to be assessed. In this study, the effects of feeding a purified BBP, avidin, to honey bee larvae and adults were determined. A realistic larval dosing regime was developed by estimating the pollen content of brood food in the field and adding avidin to artificial diet at rates that simulated the presence of avidin-expressing transgenic pollen in brood food. Larval survival and development were unaffected by avidin in assays which simulated larvae receiving pollen expressing 0, 4 or 40 $\mu$M avidin at concentrations of 164 $\mu$g pollen per mg food for the first 2 days and 880 $\mu$g pollen per mg food thereafter. Food consumption and survival of adult bees were also unaffected by avidin added to pollen-candy at levels corresponding to pollen expression of 0, 6.7 or 20 $\mu$M avidin