Insects Aren’t ‘Little Robots’ – So Scientists Are Rethinking Their Welfare
Insects Aren’t ‘Little Robots’ – So Scientists Are Rethinking Their Welfare
Science chats with an entomologist and an expert in animal ethics who are monitoring how researchers report on the ethical treatment of insects
Scientists have long assumed that insects and other invertebrates can’t feel pain. As a result, these creatures are often left out of the legal and ethical guidelines that require mice, monkeys, and other laboratory animals to be treated as humanely as possible. But what would it look like to broaden these protections to the millions of fruit flies, beetles, mosquitoes, and other insects used in research every year?
According to Bob Fischer, a philosopher at Texas State University who specializes in animal ethics, the current lack of oversight means that research insects are sometimes used in unnecessarily large numbers and can be vulnerable to both neglect and dissections without the use of anesthetics—a practice that is considered inhumane in vertebrates. In addition, many academic journals don’t require scientists to detail the treatment of research insects in their publications. Fisher’s colleague Craig Perl, an entomologist at the University of Stirling, says this lack of transparency can threaten reproducible science and may even undermine people’s trust in the science itself.
But as researchers accumulate evidence that insects may be able to experience pain—and discuss “at least a realistic possibility” that many may experience some form of consciousness—attitudes toward insect welfare are changing. To measure how this shift is shaping scientific practice, Fischer and Perl recently joined a team of scientists that trawled the scientific literature for examples of researchers reporting on the ethical treatment of their laboratory insects. Their study, published last month in PLOS One, surveyed more than 1300 papers from 15 journals over 20 years.
Fischer and Perl talked with Science about their findings, how scientists currently think about insect welfare, and what guidelines they think are necessary in the future.
Q: How did you get interested in insect welfare?
Bob Fischer: Entomologists tend to assume there’s no reason to be concerned about insects, as though they’re just little robots. But when we started digging through the literature on the cognitive capacities of insects, we came to think that it isn’t so straightforward. No, we can’t confidently say that insects feel pain, but there is enough evidence that we think some precautionary measures make sense—measures that, we think, also serve some other foundational scientific interests, like reproducibility.
Craig Perl: Public perception, particularly among younger researchers, does seem to be changing. When I’ve been at conferences over the past couple of years, younger Ph.D. students have approached me and said, “I’m doing these surveys, and I’m really worried about my bycatch. I don’t want to be killing animals that aren’t contributing to my research. What can I do?” And I’m like, “That’s a great question!”
Do people tend to be more concerned about certain insects over others?
C.P.: A lot of people are generally very fond of bees.
B.F.: There are several factors that help the bees out. They’re big, they’re cute, and the environmental movement has made a huge effort to get people to think about pollinators. We’ve got these videos of them rolling balls around that people find compelling and charming. But we also have interesting evidence of pain in bees.
Q: What trends did you discover when you surveyed the scientific literature?
C.P.: One thing I noticed when I was delving into the data was the euphemistic language that gets used, where the crucial thing missing was whether an animal had died or been sacrificed, and it had not been explicitly mentioned but could be inferred from the methods. We did see an increase in ethics statements—mostly driven by the journal Animal Behavior, which requires ethics statements for studies that use invertebrates. But even when we excluded that journal, there was a significant increase, which when you’re coming from zero is quite easy. Even though the effect is quite small, it does at least point in a fairly positive direction.
B.F.: The trends are interesting, but a lot of the value of the study is just pointing out how rarely anesthesia is used, when we know that these are the kinds of procedures where anesthesia would be preferable from a welfare perspective. Eighty-four percent of papers with significant animal handling or death did not report the use of any anesthetics.
C.P.: We also looked to see if people are employing any kind of a priori statistical methods to justify the sample size of insects being used. In this study, we didn’t find a single instance of someone reporting any methods to reduce animal use. It’s worth noting that, much like the use of anesthesia, people may have done this and not reported it, but amongst entomologists, it’s not something that’s part of our training. It’s not typically part of the way we approach doing our experiments, even though the use of sample size estimation could prevent wastes of time and resources.
Q: Beyond welfare concerns, why is it important for scientists to report this kind of information?
C.P.: Even if you don’t think precautionary measures are warranted, it’s still really important for scientists to report what they have and haven’t done to insects in the course of their experiments. Some anesthetics, for example, have an impact on behavior in fruit flies for several hours and sometimes days, whereas other anesthetics have a much lower impact on behavior. If you’re trying to recreate some of these experiments and you don’t know which anesthetic has been used, that could have an influence on whether you can replicate these results. Not saying exactly how an insect died can also impact reproducibility. If you kill an animal in a certain way, that may affect the expression of certain genes.
Q: In your opinion, what needs to happen going forward?
B.F.: The very first thing is just much more consistent and transparent reporting. We have another paper, published as a preprint, where we survey entomologists and try to get their take on what would be most effective and what they would value. And one of the things that they really want is more guidance from scientific societies about how to navigate this and what best practices should be. It’s a coordination problem as much as anything else.
What we need is for scientists to collectively say, “Okay, this is an issue worth spending a little bit of time on.” We can start setting up some guidance. We can give people resources that they can use in their labs. We can encourage people to think about incorporating a module on this into their undergraduate and graduate education. We can establish professional development courses so that people can get some basic training along these lines. We are doing what we can to facilitate this process—but it needs to be more of us, and there need to be larger conversations.
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