Dennis vanEngelsdorp, Ph.D., is an apiarist (beekeeper) widely known as a result of a 2008 TED talk, “A Plea for Bees.” He is one of the leading researchers attempting to understand Colony Collapse Disorder (CCD) and other factors responsible for the dramatic decline in bee populations. “Imagine if one of every three cows died,” he says. “The National Guard would be out.”
Dr. vanEngelsdorp’s research involves a multi-faceted approach to bee health, requiring an understanding of both the etiology of individual bee diseases and the large-scale monitoring of colony health. Currently vanEngelsdorp is the principal investigator and the director of the Bee Informed Partnership (BeeInformed.org), which attempts to identify management practices and environmental factors (such as proximity to different crops) which correlate to higher or lower colony mortality. He is also on the leadership team of APHIS national honey bee health survey which attempts to determine the prevalence of disease, pesticides, and parasite loads in U.S. operations.
The MOON: What is the status of pollinators such as honeybees in the world today? Please give us a brief overview.
vanEngelsdorp: In the United States and Europe we’ve seen a decline in honeybee colonies over the last sixty years. In the U.S. the decline is dramatic: we’ve lost fifty percent of our colonies or more. Worldwide, the number of colonies has increased, but that’s because countries like China, Argentina, and some other developing countries, have increased their colonies. Nevertheless, the number of colonies hasn’t kept pace with the increase in acres of crops that require honeybees for pollination.
In the United States we have stabilized in the last couple of years at about 2.5 million colonies. The USDA Statistical Service counts them every August, but every winter for the last six years about thirty percent of the colonies have died.
Beekeepers are able to replace those losses because beekeeping is unique in that, if you have one live colony and one dead one, you can split the live colony in half, buy a queen and build the dead colony back up again. But that takes time, money, and labor—all of which comes at a cost. So the fact that the number of colonies has stabilized does not mean that the industry is not in trouble; it is in trouble.
Add to that is the fact that the number of acres of almond trees in California that needs bees to pollinate them every February and March will soon exceed the movable colonies available. That coming shortage is something we’re very concerned about.
I know many commercial beekeepers, and they tell me that they spend all of the money they make on honey production throughout the year on keeping their bees alive. The only profit they make comes from pollinating the almond trees. We had really high colony losses this last winter and some of the largest beekeepers are ready to retire and go out of business. That’s a real concern.
The MOON: You say that China has been increasing its bee colonies, but I’ve read that the Chinese also have to hire women and children to climb among the branches and hand pollinate fruit trees because there aren’t enough bees to do it.
vanEngelsdorp: Yes, I’ve seen those reports too. Well, China is a big country, and there well may be areas that don’t have enough bees.
The MOON: For people who may not have heard of Colony Collapse Disorder, what are the major threats to honeybees today?
vanEngelsdorp: The term “Colony Collapse Disorder” describes a precise set of conditions that we first identified six years ago. There were no dead bees in the colony, it was apparent that the adult bees had left very suddenly, and no “robber bees” would touch the honey, which would normally happen in an abandoned hive. But in the last two years in the U.S. we haven’t seen a lot of Colony Collapse Disorder, although we’ve been looking. But bees are still dying. We went to California this winter and saw some very unhealthy colonies. But they weren’t dying of CCD—Colony Collapse Disorder. They’re dying…for a whole lot of reasons…but we have to broaden the conversation beyond CCD.
The number one threat to bees at the moment is the Varrao mite, which is a very large parasite—the size of a dinner plate if we were a bee. The Varrao mite sucks the blood of the bees, weakening them, and also excretes a spit that can contain different viruses that can kill the to the bees. Beekeepers use pesticides to try to kill the mite, but it has developed resistance to the most effective ones, so we’ve in effect created a super-mite.
The second most important cause is pesticides. There has been a lot of public outcry over neonicotinoid pesticides, which are systemic pesticides that can be painted on plant seeds and protect the plant for life. This was thought to protect bees from the threat posed by spraying, and also to reduce costs for farmers because they wouldn’t have to apply pesticides repeatedly. But the evidence is growing that these pesticides can migrate into the nectar and pollen of plants, where they are consumed by bees. Plants have evolved filters over time to keep natural pesticides out of pollen and nectar, but they haven’t had time to develop filters for neonicotinoids. There is also growing evidence that even sub-lethal doses of this pesticide may weaken bees and make them more susceptible to other threats, such as the Nosema parasite. Also, honey bees exposed to sub-lethal levels of neonicotinoids can experience problems with flying and navigation, reduced taste sensitivity, and slower learning of new tasks, all of which affect foraging ability.
Neonicotinoids have been banned in Europe, where they have a different standard for product safety. There a pesticide has to be proven safe; in the U.S., a pesticide manufacturer just has to demonstrate that a product isn’t lethal. But as we’re discovering, if you take a combination of sub-lethal threats and put them together, and you end up with a lot of dead bees. My personal concern is that people will put all their energy into banning neonicotinoids, and farmers will go back to spraying their crops five, six, or seven times a year, and we’ll still end up with dead bees.
It’s also becoming apparent that fungicides may also be a problem. They don’t kill bees, but we’re seeing that they have sub-lethal effects that contribute to the factors working against them.