Written by: Devin Juros
Edited by: Sisasenkosi Mandi
Should animal experimentation be allowed? This question has sparked active debate for centuries, leading to a wide variety of tangential disputes. Is there any type of research in which animal experimentation should be allowed? How should animals in research be treated? What animals should and should not be experimented on? These difficult questions can dig to the core of one’s moral views. In this article, it will not be discussed whether or not animal experimentation is morally permissible, as there is not enough space to delve into this complicated problem. Instead, we will try to parse out how we view different animals in research, which can tell us something about how we view animals and their right to life. This view will be investigated through the fly (Drosophila melanogaster), an animal used by the billion in research annually with much less ethical contention than mice or monkeys.
Especially in the last few years, there has been growing dissent over experimentation in mammals. Many rats, mice, and monkeys are used in clinical research, as animal testing of new drugs and treatments for various diseases is generally required before use in humans. This research often involves infecting these mammals with a disease and then attempting to treat them, which often fails in trials. This animal experimentation has pushed ahead our understanding of biology and pathology, from cancer drugs to COVID-19 vaccines. However, there has also been a growing movement toward decreasing or even ending animal experimentation, to reduce the suffering, pain, and death inflicted on these innocent animals. This movement has mainly focused on tightening restrictions on experiments on mammals. In 2018 in the United States, over 70,000 nonhuman primates (often monkeys) were used in research . It is estimated that over 14 million rats and mice are used in experimentation every year in the United States . Regulation of experimentation on these mammals and others has focused on replacing animals with other methods of research like cell culture, reducing the amount of animals used in each experiment, and refining experiments to minimize the pain and suffering of the involved animals .
On the other hand, flies (Drosophila melanogaster) are another experimental often used in the millions by labs . Similar to mammals, flies are dissected, infected, and killed, often with fewer regulations about animal care and anesthetization. As there are likely billions of flies being used in research every year, why is there significantly less of a public movement against using flies in research? A simple Google search on the ethics of animal experimentation on rats, mice, monkeys, or other mammals pulls up hundreds of articles on either side of the issue, while the search is largely empty for flies.
A potential argument to segregate mammal experimentation from fly experimentation is the claim that flies are not conscious and cannot feel suffering, so research is less morally reprehensible using flies than mammals. Some have argued that flies merely experience pain as another sense, like touch, and therefore cannot feel suffering due to pain. However, recent research has shown that this is not necessarily the case. For example, one recent study showed that flies feel persistent pain after they are injured, indicating a type of sensitization that humans also experience when they are injured . Another study has shown that flies may in fact have the capacity for subjective experience, or some type of consciousness, by studying areas of brain activation and comparing them to humans . These recent studies draw doubt to the claim that flies are not conscious and cannot suffer.
So, there are billions of flies that may be somewhat conscious and suffering every year. Compare this to the 70,000 nonhuman primates used in research every year. Why is there so much dissent surrounding the monkeys but only limited complaints surrounding the flies? This question will help us get to the heart of the moral issue of animal experimentation.
First, is it ever permissible to kill? It should be fairly obvious that we do not think killing any living thing is bad, as eating plants, treating bacterial infections, and killing cancer cells is universally considered at least morally permissible. Without killing these plants and pathogenic cells, we would not be able to survive as a species. On the other side of the spectrum, killing humans is generally or always morally reprehensible (without going too much into specific situations). Animals lie somewhere in between plants and humans on this spectrum. Yet, from our above discussion, it seems that there are some distinctions to be made within animals. It appears that it may be less morally reprehensible to kill a fly than to kill a monkey, at least as far as animal experimentation goes.
But, if it seems that both flies and monkeys have the capacity for consciousness and suffering, then why does this moral differential exist? Perhaps, we think that monkeys are “more conscious” or suffer more acutely, which is possible but, with our limited knowledge of the inner workings of the brain, this is hard to back up scientifically. And, why does the amount of consciousness you possess directly determine your moral rights?
Another possibility is that we often anthropomorphize animals and monkeys are much more relatable to our existence than flies. Monkeys have a much more humanlike anatomy and social interactions more similar to ours so it is easier for us to sympathize with them and feel that they should not be experimented on and used in research. But, should an animal’s similarities to humans determine if it will live or not?
Though this article raised more questions than it answered, it will hopefully allow deeper thinking about how we view animals and their right to life.
 Khuong, T. M., Wang, Q.-P., Manion, J., Oyston, L. J., Lau, M.-T., Towler, H., … Neely, G. G. (2019). Nerve injury drives a heightened state of vigilance and neuropathic sensitization in Drosophila. Science Advances, 5(7). doi: 10.1126/sciadv.aaw4099
 Klein, C., & Baron, A. B. (2016). Insects have the capacity for subjective experience. Animal Sentience, 1(9). doi: 10.3389/fnbeh.2015.00216
 National Center for the Replacement Refinement & Reduction of Animals in Research. (n.d.). NC3Rs. Retrieved May 1, 2020, from https://www.nc3rs.org.uk/the-3rs
 National Research Council (US) and Institute of Medicine (US) Committee on the Use of Laboratory Animals in Biomedical and Behavioral Research. (1988, January 1). Patterns of Animal Use. Retrieved May 1, 2020, from https://www.ncbi.nlm.nih.gov/books/NBK218261/
 US Statistics. (2020, February 11). Retrieved May 1, 2020, from https://speakingofresearch.com/facts/statistics/
 Yourgenome. (2015, June 19). Why use the fly in research? Retrieved May 1, 2020, from https://www.yourgenome.org/facts/why-use-the-fly-in-research
 Image source: https://commons.wikimedia.org/w/index.php?sort=relevance&search=Drosophila+melanogaster&title=Special:Search&profile=advanced&fulltext=1&advancedSearch-current=%7B%7D&ns0=1&ns6=1&ns12=1&ns14=1&ns100=1&ns106=1#/media/File:SEMFF.jpg