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Study: Pesticide and bees’ disappearance may be connected
Wednesday, July 16, 2014
By BEN R. WILLIAMS - Bulletin Staff Writer
A new study claims to have pin-pointed the reason why honeybees are disappearing, but Virginia Museum of Natural History Executive Director Dr. Joe Keiper is not convinced.
The study, which was conducted by Chensheng Lu, Kenneth Warchol and Richard A. Callahan with the Harvard School of Public Health and published in the Bulletin of Insectology, claims to have found a strong connection between neonicotinoids — a type of pesticide — and Colony Collapse Disorder, a phenomenon in which worker bees in European honeybee colonies suddenly disappear.
Honeybees pollinate the plants that produce fruits and vegetables. According to Keiper, a substantial loss of honeybees would cost the agriculture industry billions in annual revenue.
“The Colony Collapse Disorder idea is that you have what seems to be a healthy colony,” Keiper said. “It’s growing, it’s pollinating, the queen continues to lay eggs and the colony seems just fine. Then, suddenly, winter hits. Normally in winter (the bees) are going to be rather sedate ... but suddenly apiculturists (beekeepers) are finding that in the wintertime, their hives are empty. Something’s happening that’s causing the bees to leave the hive and never come back.”
Since the study’s publication, multiple media outlets have cited it as a scientific explanation of the cause of colony collapse.
However, Keiper, who has read the study, said that although “it’s not a bad study ... it’s not a real good one, either.”
One issue, he said, is the small sample size. The researchers used just 18 bee colonies in the experiment, Keiper said: six colonies were exposed to one type of pesticide, six to another type of pesticide, and a control group of six was not exposed to any pesticides.
In his opinion, Keiper said, a sample group of about 75 bee colonies would be needed to draw a convincing conclusion.
Another issue, Keiper said, is that he had never before heard of the Bulletin of Insectology until he looked up the study, which in his mind raises the question of whether the study was first submitted — and then rejected — from more established scientific journals.
“I just don’t think it’s a very good paper,” Keiper said. “I think it is suggestive, and I think there is evidence out there that nicotinoid compounds have a negative impact and could be contributing to Colony Collapse Disorder. For the people who are saying it is the primary cause of Colony Collapse Disorder, I don’t see the evidence of it.”
Added Keiper, “This is a fine pilot study. ... The study design seems good; the analysis has some question marks. This would have been something that I would have rejected. But at the same time, too, as a reviewer, I would have encouraged them to fix the analysis issues and increase their sample size.”
Colony Collapse Disorder has been extensively studied, Keiper said, and since it first was named in 2006, a variety of causes have been cited.
Aside from nicotinoid pesticides, Keiper said, one suggested cause is Varroa destructor, a newly introduced type of parasitic mite that lives on honeybees.
Another cause that has been suggested, Keiper said, is that cell phones and cell towers are somehow interfering with the bees’ ability to fly back to their hives. However, Keiper said, he has doubts about that theory.
One of the central mysteries of Colony Collapse Disorder, Keiper said, is that when it strikes a bee colony during the winter, the worker bees in the hive simply disappear.
“I don’t understand why it would only be in the wintertime that these cell towers would have an impact on the bees,” he said.
Keiper said many entomologists — himself included — believe that Colony Collapse Disorder is caused by a combination of factors, including pesticides, Varroa mites and hard winters. Individually, he said, these factors might cause only minor problems, but stacked on top of each other, they wipe out colonies.
“The problem with colony collapse is that it can become very pervasive,” Keiper said, “so in a given area, you might lose 80 percent of your beehives, so a single apiculturist might lose a source of income.”
Colony collapse can have a big impact on agriculture, too. Honeybees are used to ramp up agriculture production by pollinating more plants, Keiper said, thereby creating more fruits and vegetables. Three-quarters of all apples are the result of honeybee pollination, he said, and 100 percent of almonds are pollinated by honeybees.
Obviously, he said, honey production would be impacted as well. European honeybees were introduced to the U.S. hundreds of years ago, and there are no native species of bees that produce honey, he said.
Contrary to what many media sources might lead people to believe, Keiper said, Colony Collapse Disorder is not a new problem.
“If you go back in time — the 1920s, the 1970s — there are recorded situations where you have the disappearance of hives,” he said. “It’s not a new problem; it’s something that’s been going on for a long time. But because it’s something that’s out there and it does have an economic impact, there’s been a lot of research done by government agencies, universities and others to better understand why we’re losing our honeybees in this fashion.”
Keiper believes that because of the rapid flow of information in the 21st century through the Internet and social media, Colony Collapse Disorder has entered the mainstream in a way it never did in previous decades. Although it is a serious issue, Keiper said he doesn’t anticipate that European honeybees will go extinct anytime soon.
“Whatever is the smoking gun in Colony Collapse Disorder, eventually, evolution is going to catch up,” Keiper said. “So we’re going to end up with bees that are going to have a certain level of resistance to whatever it is that’s now causing a number of the hives to disappear.”
The real question, Keiper said, is how long the disorder will last.
In previous instances, he said, Colony Collapse Disorder lasted multiple years. Now, however, the world is more complicated, and people are introducing more unknown factors into the environment than ever before.
“In my opinion, colony collapse is going to be around for a while,” Keiper said, “and we might as well adjust to that fact.”