Pesticides damage the brains of baby bees, new research finds
News article: https://www.cnn.com/2020/03/03/world/baby-bees-brains-pesticides-scn/index.html
Scientific article: https://royalsocietypublishing.org/doi/epdf/10.1098/rspb.2019.2442
In a CNN news article published in 2020, Katie Hunt describes a scientific article studying the effect of pesticides on bumble bees. This article was very eye catching to me because when thinking of climate change two common narratives pop into my head: the polar bears and the bumble bees.
In a study by the Gill group in London, they studied how contaminated food entering the colonies effected offspring development. They did this by exposing worker bees to pesticide contaminated sucrose, imitating their nectar, at the concentration of 5 ppb. The figure below details the exposure timeline. They had a control line where no pesticide was introduced. Then they dosed the bees in their “brood development period” which is everything before adulthood. The third line of bees was exposed once they reached adulthood. Finally, the 4th set of bees were exposed their whole life. Each set of bees were tested 3 days into adulthood, and 12 days into adulthood.
The Gill group used three experiments to understand the effects of pesticide exposer in the nectar: Proboscis extension reflex (PER) conditioning paradigm, micro-computed tomography scanning, and neuropil volume measurements. The PER experiment allowed the authors to test the ability of the bee’s learning behavior by accessing their olfactory responses. The micro-computed tomography scanning is a method they used to non-destructively analyze the brains of the bees. Lastly, the neuropil volume measurements analyzed the growth of the brain for the mushroom body calyces.
All these experiments proved that the contaminated nectar substitute caused workers to exhibit “impeded developmental plasticity”. The PER experiment showed that there was not much difference between the 3 and 12 day adults despite the difference in exposure lengths. Even the pre-eclosion bees and the post-eclosion bees showed similar levels of impairment even though they had up to a 2-week difference in exposure length. There was no sign of recovery for the pre-eclosion bees. The micro-computed tomography scanning and neuropil volume measurements were particularly concerning because exposure at either stage of development was associated with the worker bees possessing smaller mushroom body calyces – a key part of the bee brain.
The graphs below depict their findings. The first graph shows the PER experiment depicting the relationship between the trial number and exhibiting the learnt response showing the bees with contaminated nectar exhibited a lower learnt response. The second graph relates the learning score to the size of the mushroom body calyces found from the neuropil volume measurements. While the control group had a positive relationship with calyces size and learning score, the same was not true for the treated group. The results from this study shows that pesticide exposure at any point in the worker bee life can have dramatic effects on the bee’s ability to learn and their brain size.
As someone who does not perform this type of research, this paper was hard to read. In fact, I had to read this study many times just to understand the point of each experiment. So, Katie Hunt had a very important job to make this study digestible for her audience. I think that she did a pretty great job making this information readable to the common audience. She concisely explained each experiment and used quotes from the PI throughout the article to supplement the information she is presenting. As far as the content of this article, I believe she did a great job presenting the information.
However, there were some downfalls to the piece. The first being that nowhere in the article did she link the paper that she was discussing. This paper is open access, and her readers might have wanted to read more into this. Instead, I had to find the PI’s website and look through every paper his group published to find the one she was referring to.
The second part of this article that I had issue with was the choice of figures. At the top of the page she linked a video called “the old man and the bee” which is misleading to the study she describes in the article. This video is unrelated to this study and instead follows a man that studies different types of bees in the wild. A reader watching this video might get the wrong idea about this study. A key control in this study is that the bees have lived their whole life in the controlled laboratory setting. In this video the man has a bee vacuum where he sucks up bees to analyze them. A reader could mistake the main researcher in the video for one that she is describing in the article. Taking bees from the wild would completely ruin the PER experiment because the researchers would know nothing about the bee’s life experiences, which could impact the learning scores of these bees. I thought this video to be an odd addition to this article when she could have chosen to add a figure that could have been more beneficial to the readers understanding of this article. For example, she could have chosen the bee timeline figure I added at the top to help the reader understand the differences between the bee groups. Especially since that part of the article was rushed and confusing. The only other image that she includes is a picture of the micro-computed tomography scanning of the bee brain. While this is a cool image, it provides nothing to the reader besides what a bee brain looks like. In the paper, they include that image with the brain parts labeled to understand the anatomy of the bee brain. She even mentions some of the brain anatomy in the article, so this image would have been more beneficial to the reader if it was labeled.
I also found the title of this article to be misleading. All of the experiments were performed on adult bees, so saying that pesticides are damaging "the brains of baby bees" is not a conclusion that can be made.
Overall, I give this article a 7/10. Katie Hunt did a great job relaying the information, but she did not link the scientific paper making it very hard for the reader to learn more. Especially when this paper is open access. She also could have had a better choice in figures to help aid the readers understanding of the article, and not have had such a misleading title.
Hi K.J., thanks for sharing these articles! I am curious if the authors of the study evaluated a single pesticide or different classes? In your research did you find if there are any pesticides that cause these negative cognitive effects to a lesser extent?
ReplyDeleteHey Mike! The authors specifically used imidacloprid which is apart of the class of pesticide called neonicotinoids. These pesticides are commonly found on the flowers that the bees pollinate. In the paper they mention that they believed that these results are not exclusive to neonicotinoids since all pesticides build up in bee colonies. As to a specific pesticide that would have a lesser affect, I did not find one that would do so.
DeleteHello! Great analysis of the research that was done on this topic. I was wondering if you saw in the research article any discussion of whether the issue of pesticide effects on bees potentially has more of a detrimental impact than climate change in general? Maybe this is a future research direction that could be explored if it was not discussed. Regardless, it would likely be hard to 'measure' based on what exact indicator you wanted to base your conclusion on. Also, considering a lot of it would likely be based on models and estimation these authors would probably run into skepticism from the general public as well. Great work!
ReplyDeleteHi Sofia! They did not mention the affect of climate change in general as compared to pesticides, however I agree that would be an interesting future direction. Maybe a collaboration with another lab that explores these effects on bees could be in store!
DeleteGreat post! I first read the news article and was pretty impressed by the description of the scientific methods. I think one rationale for the deduction in points in previous scoring in the course has been a lack of detail on what experiments are performed. In this article, I was struck by the depth of the discussion. Oftentimes we see a news article lead with the finding and never explaining how this finding was determined. I agree that the article may not have met the mark across all categories, but I do think that the author did a nice job explaining the science.
ReplyDeleteHi Madeline! I totally agree. I really appreciated how Katie Hunt described some of the methods that this research team performed. Even though the common reader is not a scientist, I think having the context of the experiments performed is extremely valuable to the readers understanding of these findings.
DeleteNeat article and great analysis! I agree that the choices in images could have been chosen better to prevent miscommunication of how the research was performed, which is interesting as the text of the article was better than many we've seen as far as communicating the science goes. I wonder what your thoughts are on prioritizing clear figures which communicate accurate science (but may be uninteresting to the average reader) versus figures which will draw a wider audience of readers in, but may not explain the science well.
ReplyDeleteHi Katie! Great point. I'm a big advocate of the saying that a picture can tell 1000 words. So, I believe that these authors should be prioritizing images that are going to aid in the reader's understanding of the science. When I'm reading news articles I'm a culprit of skipping to the pictures in the article, so having a more informative image would be more helpful in my opinion.
DeleteThanks for the great analysis and for choosing this topic! I also found it interesting that the paper wasn't linked in the news article, especially since the article only gives the reader a surface level understanding of the study. You mentioned that this study focuses solely on bees who spent their entire lives within a lab environment as this makes it much easier to control the experiment. I wonder how a study on the effect of pesticides on wild bees would be set up? Thinking back on our discussion last week about alligators in areas with elevated PFAS levels, do you think that bee colonies in areas with elevated pesticide levels could be similarly studied?
ReplyDeleteHey Ben! Interesting question. I think that those types of experiments could be performed, but not with the methods that this team used. Since they do not know the bee's life history, using methods to test their learning could not be as accurate because each bee could have a different aspect in their life in the wild to affect their performance in the study. It would harder to make a conclusion that the way they were acting was due to pesticides.
DeleteGreat summary! I'm impressed at her ability to summarize the article in a way that would be digestible to a mainstream audience, but unfortunately it seems she wasn't immune to a misleading title in favor of clickbait
ReplyDeleteHey katie jane, great picks! Your comment about the "baby bees" title really brings me back to the comment you made in class last week about audiences taking more interest in environmental issues that affect anthropomorphized animals. I too find it very curious that they'd make the claim that worker bees bring back pesticide-contaminated food back to the baby bees in the colonies when these studies were completely focused on bees that are brought up in a laboratory environment.
ReplyDeleteThis was a great article choice! I really liked your point about the popularity of specific animals in pop culture. I wonder how in comparison to other animals, specific animal species with a "cute factor" may have an advantage of being "saved" due to quick legislative action. Also, I wonder how changing the age of the bees in future experiments could affect the results of the experiments - would the damage to the bees brains be greater?
ReplyDeleteThis was a great article! I knew that bee populations were being threatened because of climate change and other anthropogenic issues but I hadn't looked much into how. I agree that Hunt did a great job summarizing the methods of the research, which is often difficult to find in these kinds of news articles. However, I also agree with the problems you found with the article. How do you think the shortcomings of the article you listed might affect its perception to general audiences?
ReplyDeletePesticides are created to get rid of unwanted bugs and plants, so I'm surprised at the article. Was its purpose to document how it affects bees specifically or just its broad effects? I'm also curious if the reason they used bees was because we are already trying to save them? Also, is there any explanation as to why the man and the bee was included? Was it just because they both had bees?
ReplyDeleteHello, first off great review! I agree with you that the author failed to really connect the scientific articles and the news journal. I also find the title is somewhat misleading, especially with the figure. What title do you will be most appropriate in order to really demonstrate the main point of the study?
ReplyDeleteHey Katie,
ReplyDeleteReally interesting article and nice summary! I honestly had no idea that insecticides affected bees like this, I guess I always assumed that if a bee or insect came into contact with the insecticide, it would die immediately or soon after. The research authors made some very interesting points about how this mechanism of insecticide action on damaging bee brains leaves future generations at a high predisposition for being part of a poorly functioning cohort which causes a lot of instability and eventual colony collapse. Thus, it sounds like the effects of the insecticides are amplified because they create damaged generations of bees that cannot benefit their colony but still leech food and resources. I am curious what the best way to address this problem going forward is, or if the simple solution is to just cut down insecticide use?
Great review! The agree with you that the author failed to really connect the scientific articles and the news journal. Maybe the title is misleading so more people actually to click and read the article. I am curious to see if this insecticide, or a derivative, has any lasting effects on other species that carry much weight in effects of climate change.
ReplyDeleteWow! This is pretty interesting stuff. I am sure most are familiar with how bees are dying off and there is great concern for the long-term stability of their populations on Earth... I wonder if these pesticides could have contributed to this trend? Do you have any thoughts on the matter? Or if there is a good solution to this problem?
ReplyDelete