Do insects feel pain? According to new research, crickets certainly seem to - stroking and grooming a sore antenna in much the same way as a dog nurses its hurt paw. Associate Prof Thomas White, an entomologist from the University of Sydney, explained that pain is a "longer, drawn-out, ouchy feeling" distinct from a hardwired nerve response. To test this in crickets, researchers first had to give them an "ouchy." In the study published in Proceedings of the Royal Society, dozens of crickets were randomly selected for one of three treatments: some had a heated soldering iron applied to one antenna (set to 65°C - "a bit unpleasant" without lasting harm), others received the same probe unheated, and a third group acted as controls.
Crickets that got the hot probe "overwhelmingly" directed their attention to the affected antenna - grooming it more frequently and over a longer period. "They weren't just agitated and flustered," White said. "They were directing their attention to the actual antennae that was hit with this hot probe." The other crickets? Briefly perturbed, then back to cricket business as usual. White says these behavioral responses would be immediately recognizable as pain if observed in pets or friends - "which raises the question, why don't we make the same inference here?" The answer, he suggests, has to do with human history, culture, and insects' lack of similarity to us.
Science is slowly moving the dial, revealing more about insect brains, behavior, and experiences. "These aren't just little machines," says White. "They have rich capabilities to learn, to make complex decisions and trade-offs." Studies have shown bumblebees engage in play-like behavior by rolling colored wooden balls, while stressed bees show signs of pessimism. The New York Declaration on Animal Consciousness, signed by over 500 leading scientists and philosophers, acknowledges a "realistic possibility of conscious experience" in all vertebrates and many invertebrates, including insects.
Associate Prof Kate Umbers from Western Sydney University and managing director of Invertebrates Australia says it makes sense that insects could be next for sentience recognition. "Evolutionarily speaking, insects are a crustacean on land, they share a common ancestor." People underestimate insects "all the time," she says. "Humans are notoriously not very good at appreciating things that are different from them." Bogong moths, for example, navigate over hundreds of kilometers at night to a place they've never been before. "What I hope this study can do is inspire people to look past the differences between humans and insects, and instead embrace empathy... It challenges us to think more carefully about the way we interact with these species - and to not reach for the bug spray."
The question of pain is particularly pertinent for crickets - the chickens and cows of the insect world - farmed in their billions and trillions for food, feed, and research. "If they're capable of having better and worse lives," White says, "then we should take that into consideration."