If a bee colony is under stress and only a few worker bees remain, the nutritional supply of the population is in danger. To overcome the lack of food, young bees start foraging at an earlier age than normal. Scientists led by Dr Clint Perry from Queen Mary University in London state that this behavior may be linked to Colony Collapse Disorder (CCD) – a phenomenon seen in bee colonies, particularly in the USA.
To check out their theory, the scientists purposefully put pressure on beehives: The researchers removed adult worker bees from the hives and monitored thousands of the bees remaining in the hive using radio tag tracking – including young bees less than 14 days old. Normally, bees start flying out and gathering nectar and pollen after 2-3 weeks. The experimentally generated stress, however, caused the youngsters to start foraging earlier. Though the colony seemed healthy, the researchers observed that younger bees collected less food and had a higher risk of dying while foraging. An increased worker death rate, caused by natural factors like a high Varroa mite infestation, triggers a negative feedback loop. Therefore, an increased number of dead worker bees forces younger bees to start foraging before they are really ready – meaning they are less successful. The colony will get noticeably weaker and after a few weeks only the brood, food reserves and some worker bees are left.
Finally, the scientists transferred their collected data into a computer model. Their long-term goal is to be able to predict CCD in advance so populations at risk can be saved by appropriate interventions.