We ask your help! Does anyone have any information on the minimum amount (concentration, %, ....) of Carbon Dioxide required to knock out a bee? Any other insect for that matter? We know that above 60% CO2 anaesthetizes virgin queens (technique for Instrumental insemination), and we know that in the hive the CO2 levels may reach 2 or 5% and that initiates fanning. However, we can find nothing about the minimum levels of CO2 that cause any insect to keel over. Thanks for your help. Peter (U of Guelph, Ont N1G 2W1, Canada)