Colony Collapse Disorder (CCD), which has affected honeybee populations worldwide, has driven down the number of bees available for pollinating crops essential to human populations. A new study shows the number of deaths for the winter of 2013 to 2014 were lower than in recent years.
The United States Department of Agriculture recently released a new report, stating honeybee deaths last winter were just around 23 percent of bee populations. This is just above the 19 percent losses most beekeepers are willing to accept over winter months. Wintertime losses of bee populations has hovered around 30 percent a year since 2006. The winter of 2007 to 2008 saw the greatest number of bee deaths, when colonies lost an average of 36 percent of their populations.
This one-year decrease in the number of honeybees dying is not enough to suggest a trend, but the news is welcome to beekeepers, struggling to keep colonies alive and productive.
Colony Collapse Disorder causes bees to leave their hives during winter. Without shelter or warmth from other bees in their colony, the animals freeze to death. The cause of CCD is unknown, but several theories have been put forward, including the possibility the mass deaths are due to herbicides or a mite.
The Bee Informed Partnership, a group of biologists and beekeepers, has conducted a survey of more than 7,000 beekeepers, looking for a cause. They believe Varroa mites may be responsible for causing the mass deaths. The group found that apiarists who carefully controlled mite populations in their colonies were less affected by deaths during winter months.
Honeybees are responsible for pollinating around one-third of all crops consumed by humans worldwide. These tiny insects add around $15 billion a year to the value of crops grown in the United States.
Neonicotinoids, a class of pesticides, based on the chemical nicotine, were blamed by Harvard researchers for causing the collapse. Those pesticides are banned in European countries, over concerns of their effect on the environment.
"[S]ub-lethal exposure of [neonicotinoids] affected the winterization of healthy honey bee colonies that subsequently leads to CCD," biologists from Harvard University wrote in the Bulletin of Insectology.
The Varroa mite is native to Asia, and first arrived in the United States in 1987. Large chemical companies like Bayer and Monsanto who manufacture the questionable parasites are funding studies showing the Varroa mite as the cause of CCD, according to Reuters.
Researchers continue to look at possible factors which could be responsible for CCD. The phenomenon may not have a single cause, but could have been triggered by a combination of factors.