In an extended 10-day oral and contact bee screening test, 2-day old young worker bees (Apis mellifera) were exposed to a single dose rate of the lead construct, a media control or an untreated sucrose control via an oral test (50% sucrose solution) and a contact test (thoracic application). The concentration in the dose was approximately 10x the concentration applied in the field. During this experiment food consumption, bee mortality and any behavioural effects were assessed daily. There were 3 replicates with 10 bees/cage. There were 3 replicates per dose rate with 10 bees/cage. The test conditions were 33±2°C and 50-70% relative humidity. No CO2 - anaesthetization was used as young bees are easy to handle.
During the oral application the bees were fed for the first 24 hrs with the treated or control 50% (w/v) sucrose solution. During the contact application droplets were placed on the dorsal honeybee thorax.
After dosing honeybees were provided continuously with untreated sucrose solution via syringes. Food consumption was assessed every 24 hours. Therefore syringes were weighed before and after administration to the bees. Syringes were replaced daily.
Cumulative mortality was calculated as the mean mortality of all the replicates per day. Consumed sucrose solution was calculated by {amount of sucrose solution lost from the syringe per day/(number of alive bees)}. Behavioural abnormalities was given by number of bees exhibiting symptoms per day.