Crickets Show Signs of Pain, Raising Questions About Insect Welfare

A new study suggests insects may feel pain, as researchers observed crickets stroking and grooming a sore antenna similar to a dog nursing an injured paw.

Associate Prof Thomas White, an entomologist at the University of Sydney, described pain as a “longer, drawn-out, ouchy feeling,” distinct from a reflexive nerve response.

White noted that establishing pain in other species is challenging, so scientists look for behavioral cues.

One such indicator is “flexible self-protection,” where an animal directs prolonged care to a specific body part.

“You see a dog, limping, or licking its paw, or holding one particular arm – of course, we’d immediately say, ‘well that’s in pain, it must be sore’,” White said. Scientists search for similar responses to infer pain in other animals, including insects.

To test this in crickets, researchers first had to induce an “ouchy.”

In the study, published in Proceedings of the Royal Society, dozens of crickets were randomly assigned to three treatments: some received a heated soldering iron applied to one antenna, others received an unheated probe, and a third group served as controls.

The soldering iron was set to 65℃ – hot enough to be “a bit unpleasant” without causing lasting harm, White said.

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Crickets that received the hot probe “overwhelmingly” directed attention to the affected antenna, grooming it more frequently and over a longer period, White said. “They weren’t just agitated and flustered. They were directing their attention to the actual antennae that was hit with this hot probe.”

The other crickets were “a bit perturbed” but resumed normal activity quickly, he added.

White said the 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?” He attributed the answer to human history, culture, and insects’ lack of similarity to humans.

Science is gradually revealing more about insect brains, behavior, and experiences.

“These aren’t just little machines,” said 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.

Animal welfare laws are evolving, with some countries recognizing sentience in invertebrates like cephalopods and crustaceans.

Associate Prof Kate Umbers, from Western Sydney University and managing director of Invertebrates Australia, said it makes sense that insects could be next. “Evolutionarily speaking, insects are a crustacean on land, they share a common ancestor.”

People underestimate insects “all the time,” said Umbers, who was not involved in the study. “Humans are notoriously not very good at appreciating things that are different from them.”

Insects may be tiny and have more legs, but they are capable of remarkable feats and intelligence, she said. 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, that they naturally feel towards other living things.”

“It challenges us to think more carefully about the way we interact with these species – and to not reach for the bug spray.”

To date, most insect pain and cognition research has focused on bees, but the question is particularly pertinent for crickets, which are farmed in billions and trillions for food, feed, and research, White said. “If they’re capable of having better and worse lives, then we should take that into consideration.”