In cold weather, moisture must be ventilated or it can cause stress on the cluster which is attempting to keep the brood warm. Temperature fluctuation also causes stress. Chilled brood is an excellent example of stress on a colony. Too much brood for the available population to cover results in individuals on the outside of the brood nest to die. More energy is required to produce replacement individuals and energy is also required to remove the dead larvae or pupae.
Any phenomena interfering with internal efficiency is termed stress.
All these go into determination of the energy necessary to operate the colony. The queen's egg- laying rate is regulated to allow for this constantly changing ratio by the colony. Two conditions that can radically change a population balance are swarming and pesticide poisoning. Beekeeper-caused conditions include making a split or shaking a package to make increase. The best general rule to avoid stress is maintain at all times a strong colony of bees , concludes Dr. Burgett.