Black Garden Ants on Philippine Leaves Image credit: Judgefloro. Used under CC 1.0, Public domain license.
In a recent blog for the LMAC community I explained how I was obliged to deal with an ant issue in my home. In that blog I featured the picture of an ant I had captured. The ant was slowly expiring. This death drama is one I watched many times after an exterminator came to my home.
Before he came, I had to dispatch the ants myself, with quick and unflinching force. In the face of all the sudden, and slow, death, I wondered if ants suffered. It seemed to me, as they died, that they were in pain. I'm aware that their responses to threat and death might be dismissed as simple, primitive reflexes. Many researchers hold this point of view.
An article I found on the website of the Entomological Society of Canada suggests, in fact, that insects cannot feel pain. According to Dr. Shelley Adamo of Dalhousie University, insects cannot feel pain, as we understand it. He states, "The lack of output neurons in insects limits the ability of the insect brain to sew together the traits that create pain in us."
@agmoore. An ant I captured on a paper towel
And yet, despite Dr. Adamo's assertion, a search on Google Scholar yields research that suggests otherwise. There is a plethora of research articles that posit, with different degrees of probability, that ants, and other insects, do feel pain.
One 2023 article from PLOSBiology asks, "Is it time for insect researchers to consider their subjects' welfare?" The authors of the article go over research that looked for clues in insect "nervous systems and behavior". In their analysis of the research, the authors reviewed 300 studies that considered six different insect groups. They used eight criteria established by the UK government for detecting pain in nonverbal subjects (subjects that cannot verbalize their experience of pain).
@agmoore. The ant in distress. It was given a quick death after this shot
Some of the pain assessment criteria looked at the insect nervous system to ascertain whether the basic physiological equipment exists to allow for the experience of pain. The following nervous system elements are considered essential to an insect's feeling pain: (From PLOSBiology)
- 1 Nociceptors (receptors that are sensitive to stimuli).
- 2 Brain regions that that can integrate sensory input.
- 3 Connection between the nociceptors and the brain regions that integrate information.
The PLOSBiology authors (cited above) explain that insects do have nociceptors that respond to a variety of stimuli, and the niciceptors connect to 'higher order' brain regions. In the brain regions information from the nociceptors is integrated with other sensory input. These facts seem to satisfy the basic physiological requirement for feeling pain.
What other clues exist to build the case that insects feel pain?
Neurons in Drosophila (Fruit Fly) Brain
Credit: e-life the Journal. Used under CC 2.0.
The Drosophila may be the most studied insect in science laboratories. Experiments with the Drosophila go back more than 100 years (Thomas Hunt Morgan, January, 1910). To the untrained eye, the picture above this paragraph seems to show a Drosophila brain with highly integrated neurons. What does research indicate?
Drosophila melanogaster Image credit: Andre Karwath aka AKA. Used under CC 2.5 license.
A 2021 article published in the journal eLife reports that there is "functional connectivity" between neurons in the Drosophila brain, and that these neuronal signals are "integrated". This seems to satisfy the three physiological requirements for feeling pain.
I looked at another insect, the dragonfly--not related to the fruit fly. Fruit flies are in the order Diptera. Dragonflies are in the order Odonata, but the dragonfly has an interesting brain when it comes to neuronal connectivity.
If you watch this YouTube video and skip to 11.16 minutes in, you will see that the brain of the dragonfly receives and integrates information.
According to this video, the dragonfly's brain uses a 'strategy' that allows it to predict behavior of its prey. This predictive predator strategy requires more brain processes than simply tracking prey.
Behavior
In addition to the basic physiological basis for feeling pain, there are behavioral clues researchers look for to indicate that insects feel pain. The clues described below are derived from PLOSBiology.
- 1 Do painkillers work? That is, when an insect is administered an analgesic, does this alter the response to 'noxious' stimuli?
- 2 Does the insect show the inclination, or ability, to choose between noxious stimuli and potential reward? Does the insect actually weigh (called a trade-off) the reward vs. the risk? Here the scientists look for "flexibility" in the trade-off that would indicate there is some kind of "integrative processing" of information.
- 3 Does the insect show "self-protective" behavior. This would be, for example, tending a wound. Or rubbing and grooming a wound.
- 4 Learning. Does the insect seem to learn from being exposed to noxious stimuli and does this learning lead to avoidance of that noxious element?
- 5 Does the insect show an interest in analgesics? This would involve actually self-administering the analgesic, or a preference for the location where an analgesic might be found. This interest in pain relief (analgesics) might even be demonstrated when the insect chooses an analgesic over another "need", such as food.
An article from Smore Science addresses an insect's ability to learn and to avoid pain. The authors cite an experiment where a fruit fly's leg is wounded, deliberately. After the leg heals, the fruit fly's other legs become hypersensitive. The fruit fly demonstrates avoidance behavior: "After the animal is hurt once badly, they are hypersensitive and try to protect themselves for the rest of their lives,” the authors explain.
Cockroaches Feel Pain?
One surprising piece of information I picked up in my reading about insect pain is that cockroaches rate high in the scale of pain sensitivity.
Madagascar Hissing Cockroach Image credit: Husond at English Wikipedia. Used under CC 3.0 license.
A 2022 article in the journal Advances in Insect Physiology explains how different insects rate on the UK pain scale described earlier in this blog. Using that UK list of criteria, these authors found that strong evidence exists for pain in (adult insects) two orders: "Diptera (flies and mosquitoes) and Blattodea (cockroaches and termites). The authors also found substantial evidence of pain in " Hymenoptera (bees, wasps, ants, and sawflies), Orthoptera (crickets and grasshoppers), and Lepidoptera (butterflies and moths). Insects in this group satisfied 3-4 of the UK criteria.
Why Do We Care?
I care. I've killed a lot of ants over the past month. Although many times I was angry with them for invading my home, I always felt regret that this worthy enemy had to be killed. In killing the ants, I didn't want to inflict any more suffering than was necessary to reclaim my home. The question arose: were they suffering, or was I anthropomorphizing these arthropods?
There is a larger concern when considering the possibility (probability) of insect pain. Increasingly, the research community is acknowledging standards for treatment of animals used in experiments. Is it ethically imperative that we extend this protection to insects? I can imagine the uproar in the research community at such a ruling.
A quote from the Advances in Insect Physiology Journal states the issue clearly:
From an ethical standpoint, whether insects feel pain is an urgent question. There are currently no guidelines for considering their welfare...and they are almost universally excluded from animal welfare legislation.
The insects are excluded because traditionally it was believed they do not feel pain.
But what if they do?
Conclusion
I recognize that many of my readers will dismiss this subject out of hand. It complicates life to think about insects feeling pain. So much research that advances human medicine is based on insect research. Will that research be impeded by worrying about insect welfare? I don't have any answers, but I think we should all understand the choices we make. Learning more about insect pain will advance that understanding.
Thank you for reading my blog.
https://esc-sec.ca/2019/09/02/do-insects-feel-pain/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10234516/
https://www.qmul.ac.uk/media/news/2022/se/insects-may-feel-pain-says-growing-evidence--heres-what-this-means-for-animal-welfare-laws.html#:~:text=According%20to%20the%20framework%2C%20this,crickets%2C%20and%20grasshoppers%20fulfil%20three
https://www.sciencedirect.com/science/article/pii/S1369702111701134
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8616581/
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/diptera
https://entnemdept.ufl.edu/creatures/misc/odonata/odonata.htm
https://www.smorescience.com/do-ants-feel-pain/
https://www.sciencedirect.com/science/article/abs/pii/S0065280622000170
https://eprints.lse.ac.uk/117533/
https://www.understandinganimalresearch.org.uk/what-is-animal-research/a-z-animals/fruit-fly#:~:text=The%20first%20documented%20use%20of,work%20with%20the%20fruit%20fly.
https://pubmed.ncbi.nlm.nih.gov/10441753/
https://www.smorescience.com/do-ants-have-brains/
https://www.frontiersin.org/articles/10.3389/fnbeh.2010.00028/full
https://academic.oup.com/icb/article/53/5/787/733390
https://isctj.com/index.php/isctj/article/view/257
https://www.qmul.ac.uk/media/news/2022/se/insects-may-feel-pain-says-growing-evidence--heres-what-this-means-for-animal-welfare-laws.html
https://dtermination.com/do-ants-feel-pain/
https://esc-sec.ca/2019/09/02/do-insects-feel-pain/
Nicely written article on insect pain @agmoore!
The topic on whether or not ants can feel pain is not one I had ever considered before, because it is very obvious to me that they indeed feel pain.
All we have to do really is just look at the social behavior of ants. They are very aggressive in defending their colonies usually, and they flee in the face of immediate life threatening danger while still trying to re-organize the chaos. They have both a well ingrained flight and fight response.
The way they die it looks pretty obvious too that they feel pain.
If these behaviors resemble ours, (which I would say they do in some ways) then it's just a common sense thing and the argument would be "Prove to me they don't feel pain then." Although I love science, at certain levels some truth may get lost in the equations from time to time.
It's an interesting topic, stacking comparisons between different types of insects and the how's and if's of their painful experience on this planet.
I think it's generally painful for everything to exist on this planet in some capacity.
Yes! But that's not good enough for science. In order to be persuasive, in order to convince at least a few people to change behavior, I have to prove my case. I always acted as though they feel pain. My kids (middle-aged!)are upset with the whole ant thing. That's the ethic in our house. They know I can't live with them, but they don't like to think about the killing.
Besides being a valid philosophical point, I remember something Darwin said (not exactly). He mused about the cruelty of a divine plan--if there is such a plan--that allows parasitic wasps to exist, to build their nests inside another living being. Darwin obviously believed in insect pain :(
Thanks for the thoughtful comment.
I'm speechless. I don't fail to recognize that we must protect our homes, but to think that all the insects we kill daily even without realizing it will no longer be the same after knowing they do feel pain--that roaches "rate high in the scale of pain sensitivity," OMG!--. The sensitivity to pain that insects "may" have is not an issue I haven't thought about, but I guess I'd rather not know, since I can't help but serve as an exterminator on a daily basis. We have a yard with plants and live near the beach in a tropical climate; you can figure out what the insect issue is like here. They're even a public health problem when there are outbreaks of dengue fever, for example. God, and cockroaches; I have always seen them as walking infection, and I'm particularly sensitive to them; I smell them from a distance and hear them moving around; it's very annoying, but as disgusting as it can be, I don't want anyone, including myself, to inflict pain on any creature.
I don't know if it's enough consolation for me that I've always been careful not to let insects suffer; I always try to give termites, cockroaches, mosquitoes and ants a quick death and with respect to other insects, if they allow me, I even help them to return to the yard, as it happens with grasshoppers, dragonflies, bees and even some garden cockroaches.
This is a very disheartening subject but, as usual, an amazing post. What a good read!
PS. Right now I'm thinking of that Fly in Blake's poem.
I love Blake's poem. New to me. Thank you!! As I wrote this, I was thinking of the Jainists, wearing masks over their mouths to avoid inadvertently inhaling insects.
What do we do? It just makes it harder to do what we feel we have to do. But, as you say, always with mercy.
As for cockroaches--ugh. When I first moved to NYC as a child, they infested our apartment. I could hear them at night. And, you're right, they have an odor. They are filthy, disease-carrying bugs. They have to go.
Thank you for your sincere, thoughtful, and even passionate comment. I have been upset about the ant saga, but, just like the cockroaches, they have to go.
Life is complicated the more we think, isn't it? And yet, we have to think.
Hope you a peaceful week and those foul cockroaches don't darken your doorstep.🌈
Glad you liked the poem. I love it.
I thought that Jainists sounded familiar, so I checked. Thank you for the link. I think I read something a long time ago or some teacher told me about them in my college days; we humans are very interesting and weird creatures. Right now I try think about all the things we're not seeing and immediately try to drop the idea because otherwise I won't sleep, haha.
Very good publication @agmoore, this is a somewhat complicated issue and with some controversy, as there will always be the side that will say that they do not feel pain and those who will say yes. The nervous system of insects is very different from ours or any mammal, so it is said that if they feel but not to the same degree as us, there may also be variants between insects, part of this is already reflected in some segments of the post. Another interesting thing is that they have a nerve cord formed by ganglia, so if they lose their heads the functions are assumed by these ganglia, so there are insects that can live for a while without head and die because they can not feed and so on, this is useful for some like mantids, as sometimes females remove the head of males in mating.
It is clear that they feel and therefore react to physical stimuli, the question would be to know to what extent they suffer, even caterpillars squirm when stung by ants. I have seen many entomologists in groups dedicated to sharing knowledge about insects debate on the subject, there are always divided opinions. I had read this post a few days ago, but today I come to comment. Hope all goes well, best regards @agmoore.
Hello my friend @abneagro,
I wondered what you would think about this, because you do research with insects. Of course, we can't know for sure. But shouldn't we err on the side of the insects? Imagine getting that wrong and inflicting needless suffering on the creatures.
I know it's a difficult issue, because they compete with us for space and resources. Of course we can't let them 'win'. But in dealing with them, perhaps we should try to devise methods that inflict less suffering. I think things like glue traps are especially cruel.
Thank you for commenting. I also hope you and your family are well. I hope peace prevails in your community. Peace seems to be a rare commodity these days.🌺
The fight against insects is never easy because they attack in large quantities, for industries it is much easier to sell very powerful chemicals to kill them, probably a slow and agonizing death for insects.
On the other hand, I am an agronomist engineer and my area is agricultural entomology, so I receive very often questions from acquaintances asking me for help to eliminate some arthropods that damage their plants, it is always necessary to see the affected place because sometimes the problem is not insects or other arthropods, there are also diseases, deficiencies or microorganisms that damage plants, but due to ignorance of many people usually blame insects for everything. In general, whenever I find insects damaging plants I try to implement more natural methods of control, for example, the use of their natural enemies for them to control them (biological control), I think this would be the least harmful method because it seeks to replicate what would originally occur within an ecosystem, sometimes plants when eaten by pests release compounds into the air to attract predators of pests that attack them. Also "trap crops" are often used, this means that very close to a cultivated area, places are selected to grow other attractive plants so that pests are interested in these and not in the crops from which we will obtain some benefit.
There are many methods and techniques that can be used, but I believe that none of them guarantees a quick death of insects 😞, but perhaps more respectful. Glue traps are more useful to collect specimens and thus know which are the most abundant in the area where the traps are placed, so you can create strategies to avoid possible pest attacks. Insects and other arthropods are part of the most attacked living beings on the planet, they are prey or food source of many forms of life, so evolutionarily they have great qualities to continue living, for example: camouflage, adaptation, poisons and a very high reproductive rate, a single female can bring hundreds of offspring into the world. Sorry for responding very late, but I'm back and hope to be able to comment more often and contribute more posts continuously, a hug @agmoore. 🙂🙂
This is amazingly indirect, and effective. Sounds like a great strategy.
I really appreciate your response. I have so much respect for what you do. It strikes the balance between protecting human interests and showing regard for other creatures on earth. In the end, we all share the same planet.
Every time I read something you've written, I learn.
Peace to you and your family, @abneagro
It looked like a flower to me 😂😂😭
It never occurred to me if insects could feel pain or not.
Although sometimes their wiggling of legs when dying, it does remind me of suffering
It is quite beautiful, you're right :)
We have always been careful with insects in my house. Try to save them, when possible. Take them outside. But, if they are endangering me (like a poisonous spider), or invading my space (like the ants), then they will be killed. But I always suspected they could feel pain. And, since I didn't know for sure, I always acted as though they could.
This makes it harder kill them now, though. Especially cockroaches. Ugh!!
Thanks for reading and commenting my young friend, @seki1
Excellent post!
I also recently had an ant invasion. I always feel sorry about poisoning them, but I can´t allow them in my home either.
They are determined. Every benign method I tried failed. They compete with us for territory and resources. That's what it amounts to, I guess. We have to win.😞
Thanks very much for the comment and the support. Much appreciated🌺
You know, I love ants! I wrote 2 long posts about them, maybe you want to check them out.
https://peakd.com/de-stem/@stayoutoftherz/ants-general-facts-ameisen-grundsaetzliches
https://peakd.com/de-stem/@stayoutoftherz/ants-part-ii-about-caste-determination-and-reproduction-ameisen-teil-ii-kastenentwicklung-und-reproduktion
Wow! I just read both posts as I munched on my lunch. If this material had been packaged in a book, I would have bought it :)
You truly know your stuff. I've always been fascinated by insects, although I am not a 'scientist'. I have read enough about ants (and also written about them in the past) to thoroughly understand and enjoy your material. It is just wonderful!
Many thanks! I am flattered.
Thanks for your contribution to the STEMsocial community. Feel free to join us on discord to get to know the rest of us!
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Since most of us don't care a jot about the lot of the factory-farmed animals we consume, I think it unlikely that the insects have a chance of garnering much sympathy. Besides, the ants ate all my strawberries!
🙁
I think they would have taken over the whole house if I hadn't stopped them. In any war, though, we can show regard for the enemy as we dispatch them?😇
i live in a villege and much aware of the other species as well. i know the purpose and work of maximum insects around us. every creature of ALLAH has their duties. we have had knowledge of them.
Thank you, yes. We all have our place in the scheme of life. Respect for each creature, each being.
Thank you for reading and for your thoughtful comment, @rai-humair
I myself have seen a lot of all these things in the village, they look at us in the same way above the leaves.