Shelley Adamo: Consider the Invertebrate
Dr. Shelley Adamo is a full professor at Dalhousie University in Halifax, Nova Scotia, Canada. An internationally recognized expert in the field of ecoimmunology and comparative psychoneuroimmunology, Dr. Adamo has an enormous amount of scientific experience in both the lab and field. In addition to her stellar career in academia, she has also brought her expertise and knowledge to the public, as she was recently asked to testify before a Canadian senate committee to discuss whether or not insects feel pain.
During Shelley’s recent visit to my university, I took the opportunity to sit down and talk to her about appearing before the senate, the concept of pain in invertebrates, and the plight of the insect world in general.
Adam Hasik (AH): You’ve recently appeared before the Canadian senate to talk about your work. How did that come about?
Professor Shelley Adamo, Invertebrate Behavioural Physiology, Dalhouse University (SA): Well I’m from Nova Scotia, and lobster fishing is a big deal there. It’s sustainably done (we think), and it actually maintains these small villages that are outside of the main city of Halifax.It’s their main livelihood, and the whole community is built on that economy. I was contacted by the president of the lobster fishing association. They wanted to know if lobsters felt pain, because they were having difficulty getting their product into Europe, because there was some concern that the lobsters were suffering in transport. They wanted to know what we knew about suffering in lobsters.
So I was looking into this problem for them. It’s a very difficult problem. There’s a difference between nociception, which is the reflex you have when something damaging happens, and pain, which is the psychological effect of that damage. In other words, you can have someone who is paralyzed and has no feeling from the neck down, and you could put a flame over their hand and their hand would jerk away because of a spinal reflex. But they would feel no pain, and if you closed their eyes they wouldn’t even know that you’d done it. Pain is a psychological manifestation of despair and all of these negative emotions that people, and some animals, have. The question is, how broadly applicable is that? And what kind of brain do you need to support that? And of course the other difficulty with this, and this is where it runs into philosophy, is that you can never actually know what another animal is feeling. We infer what the dog or the cat is feeling, because we’re all mammals and we have some sense for that. But it’s very difficult when you start talking about a lobster, whose brain is very different from ours and has a very different natural history. We can’t really infer very much, when you stare into those beady little eyes, you really don’t get a sense of anything.
AH: But that doesn’t mean there’s nothing there, right?
SA: Absolutely. It just means that we’re not going to be able to rely on the tools that we use when we think about pain in other animals. So we have to look at the central nervous system (CNS), which in insects and lobsters is fairly simple. They don’t have a ton of neurons. They have a lot, possibly around 500,000, but we have around 80 billion. It’s a huge difference in number. So I came to the conclusion that they probably don’t feel pain.
You have to devote a certain amount of your brain to neuronal space to have the type of connections that cause pain. In humans, we know that pain occurs because you basically sew up a lot of related areas in the brain. The part of the brain that’s important for emotion (the amygdala), the part of the brain that’s important for memory, all of those are connected in a big super network, and when they all get co-activated, you get pain. It requires a number of brain areas, which all do different things that contribute to the psychological experience of pain. Now we don’t know much about lobster brains, but we know a little more about insect brains, and they don’t seem to have those networks. They have a much more simple type of connection across areas.
For example, the insect brain has two very complicated areas that it does advanced thinking in, for lack of a better word, which are the central complex and the mushroom bodies. The mushroom bodies are important for memory, the central complex is important for navigation and such, and that’s where they do a lot of their integration. Those two areas are not directly connected at all. There’s probably small indirect connections, but not only are they not directly connected, they have very few output neurons. It’s more like a ping as opposed to sending massive amounts of information the way your amygdala does to the frontal lobe. We have a big highway of information, whereas the insect brain just gives a ping. So it’s not impossible that they have something like pain, but it’s going to be a very different concept. Is it still pain if there’s no memory, no emotion, no cognition? Maybe it’s still unpleasant, but you can see how it’s a different thing.
AH: Switching to a different plight of our invertebrate friends, there’s been a great deal of talk lately about the insect apocalypse. How much danger do you think we are actually in of seeing mass insect extinctions?
SA: The good news is that insects are incredibly good at reproducing. So if we give them a chance, insect populations can rebound quickly. There’s lots of examples where insects will get wiped out by a fungus or something and they will come back next year. You can ask anyone who has tried biological control of insects, you need to keep reintroducing the agent. Insects are very good at that.
But it’s difficult to know exactly what is going on. We’re seeing these drops in numbers in some parts of the world, but not all parts of the world. Interestingly enough, when I was at an entomological society meeting in Vancouver, some of the agricultural entomologists who are doing surveys and trying to capture invasive species are not seeing a decline in biomass and insects. It doesn’t seem to be everywhere, but it does seem to be in a lot of places, which is not reassuring. If we knew why they were dying, that would definitely be helpful, in terms of deciding how nervous we should be. Insects do so much for us, they pollinate our plants, but they’re also our garbage disposal. They fulfill a large number of niches, and they’re also important as food for lots of other animals. If you like birds, you need to love bugs. Because without bugs most nestlings will starve to death, most birds being insectivores.
I’ve just started a collaboration with people at a Canadian University who work on birds, to try to see what sort of baseline old data we can dig up for my province, Nova Scotia. Then we want to collect some new information on what’s happening with our insect numbers. So when it comes to the numbers, I am concerned enough to join the collaboration. I think we really need to learn what’s going on, but at the moment there’s enough negative information in the data that we should be concerned.
AH: A lot of people are blaming climate change for this, but there are other factors, surely?
SA: Yes. If I had to take a guess without knowing everything, I’m guessing it has more to do with pesticide use and the chemicals we put in the environment. In Nova Scotia at least, it’s not climate change, because bugs love warmth. And Nova Scotia is not warm, we’re at the northernmost range for most insects. They are LOVING climate change! We can blame climate change for a lot of things, but in Nova Scotia at least, it’s not causing the decline in insects that seems to be happening. Because we’re having a decline in the ability of barn swallows and other birds to fledge their young. So we know that something is going on, but we’re not sure what the driver is.