Suppression of ovary development of worker honeybees by association with workers treated with Carbon Dioxide

Newly emerged worker honeybees (Apis mellifera L.) aged less than 24 h were placed into queenless cages and given a section of empty drone comb and unlimited supplies of honey, water and pollen. Cages were kept in an incubator at 34 ± 1°C. Workers treated with a IS-min exposure to CO₂ at 0-3 days of age produced significantly fewer eggs than controls that received no CO₂. Workers in queenless cages for 4-6 days before CO₂ narcosis had egg production equal to that of controls. Thus CO₂ had no apparent effect after the workers had been queenless for 4 days. In a second study, 5 untreated workers shared cages with 25 sisters that had been treated with three 15-min doses of CO₂. Association with the treated workers retarded ovary development of the untreated cagemates when compared 10 sister bees in identical cages that contained no bees given CO₂, Cages with treated workers consumed only 17% as much pollen as controls. So low pollen consumption may have reduced the total amount of protein that was available and shared within the caged population. Since oogenesis requires protein, a lack of protein may have retarded ovary development.