These days, a beekeeper can’t walk down the street without being asked about the bees’ mysterious demise, but answering this question has become so complex and controversial, few are willing to try. Just visit the comment section on any article about this topic; you’ll find opinions running rampant and links to studies hurled back and forth like spit balls. Despite the inevitability of this occurring in my own comment section, read on for an exploration of this many-faceted issue.
One of the most frustrating aspects of the bee crisis is that most of the people writing about it, reading about it and studying it are not beekeepers. Every article begins with a tiresome explanation of “Colony Collapse Disorder” and a spiritless summary of why average people should care about bees. These boresome paragraphs studded with meaningless statistics and factoids often take up more than half the article. Leaving very little room for a discussion of the potential causes, which are often listed with minimal details: parasites, viruses, fungicides, pesticides, lack of forage, climate change. Followed by a declaration of uncertainty: Scientists are still unclear as to why our bees are dying. As an alternative to this introduction, I will instead focus on how bees live and function so that the reader will have a basis for understanding the myriad of stressors the bees face and how these stressors might impact the bees.
The first thing to know about bees is that they live in an incredibly complex society and we still don’t understand it fully. The bulk of the superorganism is made up of worker bees who are responsible for building, cleaning, and guarding the hive. They also must gather the colonies’ food (pollen and nectar), feed the population and keep the larvae and developing bees warm. Each worker bee goes through a series of jobs that changes as she ages: the youngest workers are nurse bees and house keepers, the oldest are foragers. A healthy colony needs an ample workforce: when the population of worker bees dips it has a domino effect. Without sufficient workers a hive may become unkempt which can lead to viruses, diseases and parasites which then exacerbate the problem. An underpopulated hive could also face starvation if there are not enough bees to forage. It might become vulnerable to robbing, beetles or moths without a proper guard at the front door. A lack of nurse bees could result in chilled brood or the queen, who is responsible for laying all the eggs, may stop laying because there are no bees to care for her young. Eventually, the hive reaches a point of no return. They don’t have sufficient adult bees to raise the workers required to overcome whatever obstacle faces them and then– collapse.
You might already see how one problem in the hive can bleed into another, which makes it incredible difficult to discern the original cause of a colony’s decline. To further complicate things, the intensity of these stressors can be altered by a number of variables: location, weather, temperature, forage, management choices, genetics and pesticide/fungicide exposure.
Weather is a common stressor: drought, cold, or overly wet years can have huge consequences for bees. In California the drought has meant many beekeepers have had to feed sugar water to their bees year-round or move them out of state because the lack of rain also means a lack of forage. On the East Coast many beekeepers attribute their losses to long, cold winters. In the Pacific North West a rainy spring can keep bees trapped in their hives when the foraging is most crucial. Weather conditions, temperatures, forage and pests can change dramatically by location so, beekeepers in one part of the world often struggle with very different stressors from beekeepers in another part of the world and even in the same location, these stressors can change from year to year.
There’s also a huge range of management styles in beekeeping. Some beekeepers consistently feed sugar water, raise their bees on foundations and treat with chemicals for mites while others allow for natural foraging, comb and rely on genetic strength for mite control. Some beekeepers inspect their hives once every two weeks and other inspect twice a year. Some beekeepers use Langstroth hives, others use Top Bars, Warre or something of their own design. Some beekeepers are hobbyists whose few colonies enjoy a permanent home and others are migratory beekeepers who move thousands of hives monthly for pollination services. These personal decisions could also play a role in a hives success or failure.
Additionally, genetics have a significant impact on whether a colony survives. Some races of honey bee do better than others in certain environments. All queen breeders are not created equal and all queens are not, for that matter, either. You could have two colonies, of the same genetic line, side by side and one would thrive while the other failed, solely based on their genetic strength.
There are many types of pesticides and fungicides and the level of exposure bees have to them can vary dramatically based on type, application practices and plant types. Also, some studies have shown that certain pesticides become more harmful to bees when they are combined with certain fungicides or other pesticides (Source 1). Therefore, each location may present the bees with a different toxic cocktail of chemicals. However, individual colonies exhibit unique floral preferences based on the needs of their colony, so, when there is a diverse offering of forage for bees, the bees may be able to avoid plants that are heavily treated with chemicals. So, even when two colonies are next to each other, they may not forage on the same plants and could each be exposed to both different kinds of pesticides and at different levels.
The Driving Force
Establishing causation with science is not easily done and based on what I know about bees, this seems especially true when it comes to bees. Consider all the variables above. How can you study bees in a controlled environment and still have it reflect a natural one? How can you study colonies in natural environment when you have little to no control over the variables? Also, a good study should follow the subject colonies for years because the honey bees’ most admirable quality is their resilience. It can take months or years for a struggling colony to finally collapse. With that said, I cannot claim that I know absolutely what is killing the bees and there are certainly many factors involved. But, what I can do is provide some compelling studies and adjourning logic to support my conviction: that systemic pesticides are the driving force behind increased honey bee mortality.
Neonicotinoids are a popular systemic pesticide. Originally, they were meant to be a way to attack pests without harming pollinators. The idea was that the poison would be inside the plant, so that when an insect munched on a leaf, it would die, without the poison having to be applied topically (sprayed). Apparently, no one considered that this poison would now be present in the pollen and nectar of the flowers that plant produced. Or that it might spread from one plant to another through the soil or ground water. Because this pesticide is systemic, it systematically contaminates the environment. You can read studies about how systemic pesticides have been found in wildflowers near treated crops here, here and here. In fact, a new study found that there were higher levels of the pesticide in wildflowers surrounding the crop than in the crop that was treated, suggesting that this pesticide can build up in the enviornment over time (Source 1). Check out this graphic from The Xerces Society that explains how systemic pesticides spread.
When honey bees collect pollen and nectar they store it in their hives and consume it slowly over a series of months. This means that bees are receiving small doses of poison, continuously. There is a growing body of scientific research that links this systemic pesticide to altered behaviors and death (Source 1). Exposure to various kinds of neonicotinoid pesticides has been shown to:
2) Impair their physical ability to fly (Source 1).
6) Reduce hygienic behavior (Source 1)
Effects 1) and 2) are both related to foraging and population. If the bees cannot properly fly or navigate, they will easily be lost which means they will either be less efficient in collecting food for their colony or they will die when they cannot find their way home. Both result in less food and a weakened population.
Effect 3) can result in colony failure if a new queen is not raised successfully, but even if a replacement queen is raised, the colony’s population will be reduced significantly during the period of queenlessness. Additionally, a new queen may not be as well mated depending on the time of year and that can reduce the colony’s chance of survival.
Effects 4) and 5) play an obvious role. Colonies with poorly mated queens often fail to survive and worker bees with shorten lifespans will stress the population and lead to other complications that can wipe out a colony.
Effect 6) can be devastating for a colony. Beekeepers know that poor hygiene leads to increased varroa mite levels (and therefore viruses), unmanaged bacterial outbreaks and higher populations of wax moths and hive beetles.
Effect 7) is perhaps the most significant finding. A weakened immune system makes a colony vulnerable to pretty much everything. A colony that collapses after exposure to neonicotinoids does not die instantly. It slowly declines. It might begin with a lack of food or a lack of foragers, but this eventually results in poor housekeeping and an increase in parasites/viruses and with compromised immunity they have little hope of overcoming them. This might explain why there isn’t a consistent set of symptoms for our dying bees. No one colony will die in the same way. Once weakened by neonicotinoids, they could be taken down by extreme cold, lack of forage, varroa mites or all of the above. In some cases, they might never succumb and instead limp on, not thriving, but not dying either.
It is important to read the actual scientific studies cited, not just the headlines, for several reasons. First, find out who funded the study. Unfortunately, this often seems to influence the conclusions of the studies. Second, the studies are often flawed. Think about all the variables I mentioned above. It seems nearly impossible to create the level playing field needed for research when it comes to honey bees. Even the studies with findings that support my perspective are usually flawed in some way. The good news is that beekeepers have an advantage when it comes to seeing these flaws.
When reading a study, if possible, read it the whole way through. Don’t just read the conclusion. I have found that the conclusions often downplay or misrepresent the impact of the pesticide they are testing. You also want to consider the metrics used to determine the conclusion of the study. These are often problematic. For example, a study might determine that one colony is healthier than another based how much honey they have, when this is actually not a good measure of colony health.
Take a careful look at the methods. How many hives did they look at? For how long? How were the bees exposed to the pesticide? Were the bees exposed field-realistic doses? What are field-realistic doses and how was that standard determined? We need to consider how close these conditions are to that of a typical beekeeper’s experience, but even that can be tricky given how changeable and varied these experiences are.
Another problem with methods involves “blinding”. Researchers may subconsciously or consciously influence the results of their studies if they know which test subjects have been exposed or not to the pesticides. A good study will find a way to conceal this information from experimenters.
Refuting Classic Arguments
The number of managed beehives is increasing and therefore colony loss is not a problem.
This claim uses faulty logic. Quantity is not quality. If you are a beekeeper you know how easy it is to split a hive. You had one colony and now you can call it two, but you don’t actually have more bees (at least at first) and this metric says nothing about how healthy the bees are. You could have twice the number of colonies you had last year, but if you still have 44% losses through winter, you still have a problem. The appropriate metric to estimate decline is the die-off rate within each colony.
Some studies have found little-to-no effects on bees in direct contrast with these other studies.
Think about all the variables I listed above. Doesn’t it make sense that in some cases bees would be able to overcome the ill effects of pesticide exposure? That we would not always get consistently negative results? The bees might have less stressors in their environment. They could have better forage, better weather or in the case of Australia no varroa mites! In this latest study, data was collected from bees living near oil seed rape field in Germany, the UK and Hungary. The study found negative results in the UK and Hungary, but not in Germany. However, the study found that the bees in Germany collected on 15% of their food from the oil seed rape fields, in contrast to the 40-50% in the UK and Hungary. The researchers concluded that the bees in Germany were foraging on other flower resources in the landscape and were less exposed to neonicotinoids as a result. This is just one example of how environmental differences can result in different outcomes.
We are no longer seeing the classic symptoms of “Colony Collapse Disorder”.
This is true. There was a specific set of symptoms that were prevalent for several years when the issue of increased honey bee mortality first began to receive attention. It was given the name “Colony Collapse Disorder” or “CCD”. So, why now are we not seeing these symptoms and does it mean there is no longer a problem? Once again, given all the variable and the complex synergistic relationships between them, it makes sense that we are not seeing bees die consistently in the same way. My guess is for the years during the phenomenon, there were some prevalent stressors that when combined with the systemic pesticide that resulted in a similar set of symptoms leading up to the colony’s end. Since then, the environmental stressors have shifted resulting in a more varied set of symptoms. Yet, we are still experiencing an increase in winter losses, so the problem is far from over.
Native Bees & Other Pollinators
In our frenzy to report on the plight of the honey bee, we often forget to mention our native bees. Native bee species are on the decline, but because they are not so easily linked to our economy, they are often forgotten. In my opinion, we should be more worried about these hugely important pollinators going extinct than the honey bees. They do not have beekeepers looking after them, after all. Also, the majority of native bee species are solitary and do not have the advantage of the super organism, which makes them much less resilient to stressors. Scientists have also linked neonicotinoids to a decline in song birds, bats, fish and amphibians (Source 1).
Tipping the Balance
Coming back to the resilience of the honey bees, I find myself wondering what action would be needed to tip the balance back in favor of the bees. Banning or deeply restricting neonicotinoids (which I am in favor of) will work for a time, but eventually these chemical companies will create something new and terrible to replace it. With a compromised immune system, a colony’s position teeters on the edge of collapse, and something has to be done long term to support them. This brings me to a conversation I had with Michael Bush during my time at his Bee Camp. We were driving through the desolate Round-Up Ready corn fields that dominate Nebraska, lamenting the disappearance of flowers that once grew between the cornrows, when Michael commented that the roadsides could be seeded with bee flowers and that might be enough to make the bees bounce back. Neither of us can say for sure if this would work, but I will say that bees on a good nectar flow often resemble Popeye after eating his can of spinach. Could a significant boost in floral resources charge our bees with the super strength needed to overcome their other stressors? We have to start making long-term efforts to support pollinator health and providing uncontaminated forage and habitat could be the key.
*If you intend to disagree with me in the comments, I only ask that you back up your claims with actual studies, not articles written about studies.