Colony Collapse Disorder and Pesticides, Or Save the Bees!
Bees, who needs them? They are scary, they sting and they seem to find magical ways into your securely locked home. I’m not bias, even though I run screaming like a little girl when I see one… okay maybe a little. But as it turns out we need the bees!! Who knew, right? After the colony collapse that came out of nowhere and could not be explained [at the time] everything from global warming to government conspiracy was being blamed. But now a new study helps strengthen the cause of the collapse.
Two widely used insecticides– in the class called neonicotinoids [for those of you who think you will be tested on this at the end]– appear to do significant damage to honey bee colonies over the winter, particularly in bad winters [hello global warming, I’m looking at you].
The new study, from the Harvard School of Public Health [or HSPH] replicated a 2012 finding [from the same group of researchers], the original study found the link between low doses of imidacloprid and Colony Collapse Disorder [or CCD]. This new study not only found the same link, but it also found a second insecticide which caused the bees to exhibit this behavior, low doses of clothianidin had the same negative effect on the bees.
[Loony Hint: In Colony Collapse Disorder, bees abandon their hives over the winter just to die eventually. Originally no one understood what was causing this problem, but it could wipe out as much as 90% of the affected hive.]
The team also offered proof that a popular alternate explanation was incorrect. That explanation suggested that CCD may have come from bees’ reduced resistance to mites or parasites as a result of exposure to pesticides. This new study however, found that bees in the hives exhibiting the CCD behavior had almost identical levels of pathogen infestation as the control group.
[This is a very good example showing why you need to have a control group to compare your research against by the way.]
This suggests that the neonicotinoids are causing some other type of biological mechanism in bees that leads to CCD. This makes sense considering the method of action for neonicotinoids and that low doses typically will not kill insects. Bees are, after all insects, so the study really shows that this class of insecticide induces that alternate [CCD causing] behavior in bees.
[Loony Hint: For those who didn’t read the link, neonicotinoids work because they bind to a receptor in insect brains, a receptor humans have as well, it is the receptor nicotine binds to, the key difference is that it does not detach in insect brains like it does human brains. This causes paralysis and eventually death because it permanently blocks the receptors]
“Although we have demonstrated the validity of the association between neonicotinoids and CCD in this study, future research could help elucidate the biological mechanism that is responsible for linking sub-lethal neonicotinoid exposures to CCD,” said author Chensheng (Alex) Lu, associate professor of environmental exposure biology at HSPH. “Hopefully we can reverse the continuing trend of honey bee loss.”
Colony Collapse Disorder caused untold loss in crops, bees are responsible for pollinating roughly 1/3 of them and not being able get the bees needed to pollinate crops means a shortage of food in an already delicate balancing act given population size.
Sure, save the whales, save the sharks, heck let’s save those cute little dolphins as well, but maybe we should save the bees while we are at it too.
In an interesting side note, increasing bee diversity when pollinating crops will yield a higher return, suggesting that we should not just save the bees, but make sure that we have as many kinds pollinating crops as possible.
Lu C. (2014). Sub-lethal exposure to neonicotinoids impaired honey bees winterization before proceeding to colony collapse disorder, Bulletin of Insectology, 67 125-130. DOI: 1721-8861
Rogers S.R., Tarpy D.R., Burrack H.J. & Blenau W. (2014). Bee Species Diversity Enhances Productivity and Stability in a Perennial Crop, PLoS ONE, 9 (5) e97307. DOI: 10.1371/journal.pone.0097307.s001