Stressed-out bees may be another contributor to Colony Collapse Disorder, according to a study from the Queen Mary University of London.
Bee health has been a growing concern for agriculture and food industries as the tiny insects are dwindling in number, but are still heavily relied upon to pollinate human food sources.
Though no one cause has been identified for CCD, poor diets, exposure to pesticides and parasites are all on the list of potential causes. Now, the University says, pressure on young bees could also be a factor.
Bees usually begin foraging when they are 2-3 weeks old but when bee colonies are stressed by disease, a lack of food, or other factors that kill off older bees, the younger bees start foraging at a younger age, the University says.
Researchers attached radio trackers to thousands of bees and tracked their movement throughout their lives. They found that bees that started foraging younger completed less foraging flights than others and were more likely to die on their first flights.
The researchers, from Macquarie University in Sydney, Washington University in St Louis, University of Sydney and Queen Mary, used this information to model the impact on honey bee colonies.
They found that any stress leading to chronic forager death of the normally older bees led to an increasingly young foraging force. This younger foraging population lead to poorer performance and quicker deaths of foragers and dramatically accelerated the decline of the colony much like observations of CCD seen around the world.
"Young bees leaving the hive early is likely to be an adaptive behavior to a reduction in the number of older foraging bees," said Dr. Clint Perry of the School of Biological and Chemical Sciences at QMUL.
But if the increased death rate continues for too long or the hive isn't big enough to withstand it in the short term, this natural response could upset the societal balance of the colony and have catastrophic consequences, the University says.
"Our results suggest that tracking when bees begin to forage may be a good indicator of the overall health of a hive. Our work sheds light on the reasons behind colony collapse and could help in the search for ways of preventing colony collapse," Perry noted.