by Trevor Smith
Colony Collapse Disorder, which has troubled beekeepers across the nation and world over the last decade, has been linked this week to stressed young bees, The Guardian reports. Recent developments in bee populations have forced younger bees to leave the hive to forage much earlier than they might otherwise. The stress of these journeys is likely too much for the younger bees’ bodies, which have not finished fully developing; younger bees are not able to make as many journeys in their lives between the hive and the outer world as bees who leave the hive as adults. The result, argues an article in the latest issue of the Proceedings of the National Academy of Sciences of the United States of America (PNAS), is a hive-wide social imbalance that accelerates collapse (Perry et al. 2015).
The discovery arrives in the wake of a catastrophic decade for European honey bee colonies in Europe and North America. The United States Department of Agriculture’s most recent Colony Collapse Disorder Progress Report notes that average bee losses for the winter of 2012 hovered near 22%, with numbers closes to 34% for the five years prior (CCD Steering Committee, 2012). Some bee loss naturally occurs each winter, but in the last several years, colony collapse disorder has caused loss rates to jump to a point beyond what beekeepers find is financially sustainable. The report also notes that there is not one likely cause of colony collapse disorder. Rather, a variety of factors combine to kill older worker bees.
The new study out in PNAS does not dispute this. Instead it shows why the collapses of the last decade have been so devastating. Stressed out young bees are not the initial cause of colony collapse. But once older worker bees begin to die off in disproportionately high numbers, young worker bees are required to assume an adult role in the colony much earlier than they might otherwise have, and because their bodies are relatively immature, their work lives are much shorter than the older bees, causing a new generation of younger bees to be exposed to the environmental stressors posed by foraging (The Guardian 2015). The cycle repeats, and colonies collapse. It is unclear how this new revelation might help stop colony collapse disorder.
CCD Steering Committee of the USDA. “Colony Collapse Disorder Progress Report.” June 2012. http://www.ars.usda.gov/is/br/ccd/ccdprogressreport2012.pdf
Perry, Clint J.; Søvika, Eirik; Myerscoughd, Mary R.; Barrona, Andrew B. “Rapid behavioral maturation accelerates failure of stressed honey bee colonies.” PNAS 2015: 1422089112v1-201422089
“Stressed young bees could be cause of colony declines, scientists find.” The Guardian. February 10, 2015. http://www.theguardian.com/environment/2015/feb/10/stressed-young-bees-could-be-cause-of-colony-declines-scientists-find