What’s up with the bees?

No bees here!

Bees are dying and blogs are buzzing. A phenomenon called ‘colony collapse disorder’(CCD) has been decimating bee populations in North America and Europe. Bloggers are eager to put the blame pesticides, herbicides, GMO crops and mono-cultures, but what’s really going on? What’s this mysterious bee disease, what should we do to prevent it and should we be really worried? Will our crops fail and nations starve when the bees die out? Time to review the different facts and factors involved and see if we can make some sense out of all the buzzing.

Bees: who are they and why should we care?

First of all: not every bee is a honey bee but, in the context of CCD, honey bees are all we care about. It’s the honey bees that are dying. Solitary bees, carpenter bees, bumblebees and what not are not under threat. There are in fact almost 20.000 known species of bees . Yet, honey bees are important pollinators. By buzzing around and hopping from flower to flower they pollinate the flowers and this is essential for some plant species to bear fruit. Without pollination, we’d have no  apples, no pears, no grapes (and no wine), no kiwi’s and no cacao. The list goes on . Are honey bees the only pollinating species? Not at all. We won’t see the instant demise of all of our crops once the bees are gone. Honey bees are an important pollinating species, but far from the only species. Other insects pollinate too, such as bumblebees, hoover flies, midgets and even mosquitoes. In addition, animals such as humming birds and fruit bats pollinate many crops in regions where they’re abundant. Farmers tend to utilize honey bees to pollinate their crops, since it’s simple enough to put up a couple of hives in your orchard and their honey is a nice bonus, but they’re hardly essential. As far as I could find, only a few fruit crops appear to depend on pollination by honey bees alone, such as lemon and lime. Still, honey bees do put in a lot of effort in the pollination of many of our crops and crop-yields may very well be severely reduced without honey bees around. However, it’s a gross overstatement that our world would perish and our civilization collapse without the bees. Such overstatements sell movies, but don’t really help us much otherwise.   

Colony collapse disorder: what’s that then?

The sudden disappearance of all the worker bees from a hive is what causes a bee colony to collapse. No worker bees, no food, no hive. This is not a new phenomenon, though the name CCD was only coined in 2006. Entire bee colonies have disappeared since ancient times and this phenomenon has been labelled as “disappearing disease” or “spring dwindling” (Oldroyd, 2007). However, the rate of honey bee colony loss reported in particular since the 2006-2007 season, is quite unusual. What really happens in CCD is unclear. The bees don’t die at the hive, as such, they simply disappear. They fly out and never return to their hives. Do they get disoriented and lose their way? They fly out and die elsewhere? Nobody really knows. A number of causes have been proposed for this phenomenon, primarily infectious diseases and chemical contamination of the bees’ environment with pesticides and/or herbicides.

Infectious diseases

Bees, like any other living thing, are susceptible to a number of pathogens including mites, fungi and viruses. The most prolific bee-killer is the mite Varroadestructor. This mite has been spreading throug the world since the 1960s and has, in fact, been responsible for decimating bee colonies, including domestic honey bees and wild bees. However, chemicals have been developed that kill the mites, so called ‘miticides’ and, although the mite still infects virtually every colony, the infection is under control and rarely results in colony destruction loss (Oldroyd, 2007).  In addition, it seems that the mites have become less virulent while feral bee populations have mostly become resistant. Another likely candidate for an infectious disease contributing to, if not causing, CCD is a combination of a fungal and a viral disease. Invertebrate iridescent virus (IIV6) and the fungus Nosema caranae have been linked to CCD. However, the study identifying the IIV6 has later been called into question. Another pathogen associated with CCD is the parasitic phorid fly. This fly lies its eggs in life bees and when the eggs hatch the larvae eat the bee alive. Before the bee succumbs, the larvae control the bee turning the bee into a ‘zombee’. Such a scenario might explain why the bees of CCD colonies go missing since infected bees won’t return to the hive to die. However, further investigation into the role of the phorid fly is still pending and if you think you see a zombee you can help by catching it and reporting your find on the Zombee Watch site. Altogether, although CCD appears to be linked to an infectious disease, no clarity exists yet about the pathogen that may cause it.

Pesticides, herbicides and GMO crops

First, there’s absolutely no evidence that genetically modified crops are associated with CCD. To the contrary, in areas where high amounts of GMO crops are present, such as in Illinois, no cases ofCCD have been reported. The alarmist blogs have been blaming the herbicide Round-up, glyphosate, for the death of bees, but again, there’s no evidence for such claims. In fact, the latest research shows no effect whatsoever of glyphosate on bee health. The only substances that seem to affect bees negatively are the neonicotinoids used as pesticides. These compounds were designed as relatively safe insecticides to control pest-species that damage our crops. Initial studies showed little to no effect on foraging honey bees, that might ingest the compound through contaminated pollen. However, a concurrent study indicates that ingestion of the compound might render bees more susceptible to viral diseases. Thus, the neonicotinoids are still suspect and will remain so, pending further investigation. The E.U. has therefore banned the use of these substances for the time being.

Conclusions

We still don’t know for certain what’s causing CCD. A combination of factors seems likely. Over-all, the phenomenon appears to be pathogen-related and the parasitic phorid fly seems a likely cause. A loss of plant diversity may also be a contributing factor, as may certain chemicals in the environment that render the bees more susceptible to infection. However, bee populations are already seem to be recovering, bees are not exactly on the brink of extinction. I don’t think there’s a reason to panic, but it never hurts to be cautious.