Reasons Why the Honey Bees Are Disappearing

Those who have been paying attention to environmental news over the past couple years know that honey bees have been disappearing at an alarming rate. Beekeepers across the United States and Europe have reported that their bees leave the hive and rather than coming back as they usually do, they simply disappear, never to be seen again. The loss of bees to maintain a hive usually leads to the hive's collapse.

Dubbed colony collapse disorder, or CCD, this epidemic has been a major concern for the world's food producers. Bee colonies are vital for plant pollination. Without pollination, plants don't bear fruit.

What is Colony Collapse Disorder?

Over the past few years, many hypotheses have been put forth as to why bees aren't returning to their hives. Some believe that global climate change is confusing the bees while others wonder if atmospheric electromagnetic radiation from cell phone towers is interfering with bees' delicate navigation mechanisms. Still, others believe that parasites may be responsible for the bees' disappearance.

Whether or not these elements have anything to do with bee colony collapse disorder is unknown. However, a recent study has demonstrated significant evidence that pesticides used in farming are directly related to the bee population decline over the past decade. 

The Pesticide Connection

This scientific study, undertaken by Dr. Richard Gill and colleagues at the University of London and featured recently in Nature magazine, indicates that two pesticides may be the cause of colony collapse disorder. In the words of Gill and team, "chronic exposure...to two pesticides...impairs natural foraging behavior and increases worker mortality." 

While previous studies examined the impact of pesticides on the individual physiology of bees, Gill's study focused on overall hive behavior and survival as related to the pesticides neonicotinoid and pyrethroid. While these pesticides may have subtle effects at the individual level, their combined impact on bee hive survival, whether through shared metabolic processes or reduced hive communication ability, was shown to be lethal.

The Experiment and Its Results

To simulate exposure to neonicotinoid and pyrethoid pesticides, Gill and team exposed entire colonies of 40 bumblebees each to these pesticides at levels approximating those in and around fields. The result was nothing short of alarming. The average number of bees lost as a result of the pesticide exposure, whether dead in the hive nesting box or dead due to failure to return to the hive, was about two thirds of the total against a third of the total for a control group. In the experiment, the pesticides caused a 100 percent increase in bee mortality. 

How the Research Applies to Our Understanding of Bee Colony Collapse

While this research provides strong evidence of the role that pesticides may play in colony collapse disorder, it still does not complete our understanding of the strange new bee behavior. Australian bee expert Professor Boris Baer states that it could be "an important milestone" in our understanding of the disorder.

However, Gill and other scientists like Dr. Juliet Osborne of the University of Exeter agree that this study is only a part of the puzzle. Osborne in particular emphasized the need to "understand all factors" contributing to honey bees dying all over the world. Parasites and pathogens may also have an impact. Still, others have noted that the study was done with bumblebees and that honeybees may have enough biological differences to necessitate further research on the link between pesticides and colony collapse disorder.

Only time will tell the exact cause of colony collapse disorder. However, Gill's landmark study was definitely a step in the right direction toward science understanding the reason and hopefully finding a solution to the problems threatening the global bee population.