A New-bee's Struggles

Being a frosh (our word for "freshman") and only three weeks into the semester, I haven't had much time to start on a project. That being said, I decided to do some research into the challenges bees face after visiting our small colony out in the field with Prof. Donaldson. I learned that Southern California with its desert-like climate apparently isn't the easiest environment for bees to survive in, which got me wondering about what other challenges the little ladies face when navigating the big, wide world in search of flowers. After all, bees are hardworking and wear black and yellow, and students at Harvey Mudd are also hard working and wear black and yellow - bees are practically Mudders!

Image 1. We're basically the same right?

One thing that jumps to my mind when I think about struggling bees is Colony Collapse Disorder (CCD). In the past decade, it seems that articles have popped up on news sites every-so-often proclaiming the record rates that bees have been dying off at. Of course, research is continuously being done on the multitude of causes for CCD, but I decided to look into some specific reasons for colonies to collapse.

First of all, CCD is characterized by a rapid loss of the adult bee population. Often, collapsed colonies are found with significant capped brood and food, but no adult bees anywhere in the vicinity. This is a rather haunting image - as if you were to walk one day into a house that appeared well-maintained and well-stocked with food, only to find it completely deserted.

Figure 2. A hive impacted by CCD. Note the large amount of capped brood (especially in the middle frame) with no workers.

A study done on bacteria in honeybee hives that had experienced CCD discovered that although there wasn't any strong indicator of a bacterial cause for CCD, it was strongly suggested that the Israeli Acute Paralysis Virus (IAPV) is a significant marker for CCD (or at least a minor contributor on some occasions). This is a virus that attacks every life stage and every caste of bees, with symptoms such as shivering wings, a darkening thorax and abdomen, and loss of hair. Interestingly enough, it's also a virus with a high genetic diversity - there are three common strains in the United States, and a few more in other countries.

This fact provided me with some insight into how impactful it might be to bee colonies; in freshman bio we are currently learning about HIV, another virus with a high genetic diversity. Although IAPV seems to be less genetically diverse than HIV is with its constant mutations, the fact that IAPV has many different strains likely makes it difficult to combat and difficult to stop. Furthermore, IAPV gets transferred by bee pests such as the varroa mite, a small and incredibly prolific parasite.

Pesticides are another thing strongly linked to CCD. Scientists in the EPA and USDA theorize that pesticides are one of multiple stressors that, through complex interactions, contribute to the declining populations of bees. Although pesticides are targeted at pests and weeds in gardens and on farms, they often will negatively impact innocent bees as well.

Figure 3. Information about neonicotinoid pesticides.

Neonicotinoid pesticides are one class of incredibly common pesticides that have the potential to do damage to bees at very low doses. A dose with about 50% effectiveness is at most 90 nanograms. It causes over stimulation of the nerves in bees and insects, resulting in eventual paralysis. Plants absorb neonicotinoids, meaning that any pollinator that feeds on the plant will ingest the pesticide. This also means that they can remain in the soil and in plants for much longer, causing more damage.

I think it's easy for people to point fingers at neonicotinoids as The Evil Murderer of Bees given all the evidence about its impact on pollinators, but the situation is really more complex than that. Reported concentrations of neonicotinoids in the nectar of treated plants appear to be much lower than the sublethal dosage tested for in labs. Furthermore, field trials are incredibly difficult to conduct because it is nearly impossible to control all the variables in a natural environment for bees; obtaining solid evidence is difficult. The only strong conclusion that can be drawn so far is that neonicotinoids have negative effects on pollinators like bees. It would be jumping to inaccurate conclusions to say that neonicotinoids cause CCD.

Through this entire article, readers will note that I've been sort of hedging around the question of "What causes CCD?". I've alluded to viruses that are connected with CCD, and pesticides that may have a negative impact on bees, but I haven't straight up talked about what causes CCD. I would love to just get to the point, but unfortunately there isn't a conclusive one. There is no reputable source that can or will tell us what specifically causes colonies to collapse! It would be wonderful to be able to say "this is the reason", and "this is what we have to do to stop bees from dying". Unfortunately, CCD is a multi-dimensional problem with many varying factors. There are things that we can do on a smaller level, like reading the labels on pesticides to make sure they're safe for bees, but discovering the culprit is a much larger problem.

At Mudd, a significant part of our education focuses on our impact on society - understanding that as scientists, we have the potential to shape society with our research and work. After all, I'm practically expected to have our mission statement memorized by senior year. It's only been one semester for me, but it's already been made clear to me that it's important to think about whether the things I say are true. Much of this process involves learning how to gather information from reputable sources, cross-referencing data, and considering for myself the logic presented by such sources. It's easy to simply believe in whatever we're told by newspapers and journals, but much harder to approach information with a healthy dose of skepticism. Being able to think critically about the information I'm presented is an important skill to learn as a scientist, however, because it forms the basis upon which scientific theory can evolve and grow.

Perhaps, if bees were truly Mudders, they could tell us why colonies are collapsing. Since they aren't, I've learned that we will simply have to continue the struggle to connect different factors to CCD. Logically and without jumping to conclusions.

References:

Cox-Foster, D. L., S. Conlan, E. C. Holmes, G. Palacios, J. D. Evans, N. A. Moran ... W. I. Lipkin. "A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder." Science 318.5848 (2007): 283-87.

Chen YP, Pettis JS, Corona M, Chen WP, Li CJ, et al. (2014) "Israeli Acute Paralysis Virus: Epidemiology, Pathogenesis and Implications for Honey Bee Health." PLOS Pathogens 10(7): e1004261. doi: 10.1371/journal.ppat.1004261

The Xerces Society. "How Neonicotinoids Can Kill Bees: Executive Summary."

Oldroyd BP (2007) What's Killing American Honey Bees?. PLOS Biology 5(6): e168. doi: 10.1371/journal.pbio.0050168

Media Credits:

[1]: Drawing by Flora Xia

[2]: Article by Benjamin P. Oldroyd. http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0050168

[3]: Video by NOD Apiary Products. https://www.youtube.com/watch?v=wj-h5VJqaoI

[4]: Article by Compound Interest. http://www.compoundchem.com/2015/04/14/neonicotinoids/