It turns out that bees can not only radiate pain – they can also absorb it.
In a study published last week in the journal PNAS, researchers from the United Kingdom found that bees trade exposure to heat to gain access to better food. The finding suggests that bees are not just mindless stimulus-responsive automatons, but rather conscious, sentient beings that can experience pain and engage in complex decision-making.
In other words, bees may be sentient, which would mean that they have the ability to feel and have subjective experiences.
For the experiment, behavioral neuroscience PhD student Matilda Gibbons of Queen Mary University of London, along with four other colleagues, first offered the bees a choice to drink from two yellow-labelled “high-quality” feeders with a 40% sucrose (sugar) solution, equipped with an inactive heating pad. (Bees, not unlike us, love sugar.) Different groups of bees were also offered two alternative pink-labeled feeders with 10, 20, 30, or 40 percent sucrose solution, each paired with a heating pad that was also inactive.
A bee drinks sucrose from a feeder in an experiment to test their ability to make motivational trade-offs. Pippa Agger/Queen Mary University of London.
The bees, of course, preferred the sweetest 40 percent sucrose solution. But then the researchers repeated the experiment with a twist: The yellow, high-sugar feeders were raised to 131 F—enough to cause the bees discomfort but not injury. The pink feeders, which ranged from 10 to 40 percent sucrose, remained unheated.
When the unheated feeder contained only 10 or 20 percent sucrose, the bees continued to drink from the high-sugar feeders despite the pain. But when the unheated feeder contained 30 or 40 percent sucrose, many bees migrated to it using associative memories to avoid the pain of the heated feeder while being able to enjoy a high-sugar snack.
“Instead of it being a sort of robotic reflex response, which would be them always avoiding the heat in every situation, they’re able to weigh the different options and then suppress that response,” Gibbons said.
“Work like this recent paper that shows motivational trade-offs [and] very strongly suggests that the experience of pain is in some ways quite revolutionary,” says Heather Browning, a philosopher and scientist at the Basic Animal Feelings Project at the London School of Economics, who was not involved in the study.
One reason it was revolutionary, according to Browning, was that the ability to make motivational trade-offs was an important marker in determining sensitivity. It has also been observed in hermit crabs.
“At least one of the likely roles of sensitivity for an organism, one of the reasons for it [sentience] evolved, is to help an animal make trade-offs like this,” says Browning. “It’s about helping them make flexible decisions when they have these competing motivations.”
However, this is not formal proof that the bees are conscious or that they experience pain, the researchers cautioned, given the inherently subjective nature of pain and consciousness. Even understanding consciousness in humans is still a mystery, something known in philosophy as the “hard problem.”
But the researchers say the possibility that bees have the ability to experience pain and suffering should be taken seriously, and the findings may apply to some other insects.
“Can we really say that just because bees do this, does that tell us a lot about other insects?” It probably applies to the more closely related ones, like bees, wasps, ants and maybe flies, but the farther you go, probably less so,” said Andrew Crump, a postdoctoral biologist at the London School of Economics and co-author of the study.
As revolutionary as the new research is, it won’t start a revolution in insect rights – just look at how we treat many birds and mammals despite the general consensus about their consciousness.
Researchers are at the beginning of what will likely be a long journey to better understand whether and how insects are sentient. But the findings serve as further evidence that the number of species we include as sentient may be underestimated—and by a huge margin, given that there are about 10 quintillion living insects at any given time (1 quintillion is million trillion).
The debate over who should be in the feelings club
Despite the extraordinary evolutionary success of insects, researchers in the field of animal science have only begun to investigate whether they possess consciousness in the last few years.
Until the late 1970s, researchers in the field focused on animal behavior and did not attempt to determine whether behavior gave them sentience. The animal mind—if such a thing existed—was considered a black box, best left unopened.
That changed largely thanks to the work of Donald Griffin, a Harvard-trained zoologist who began arguing in the late 1970s that animals, not just chimpanzees and mammals, are conscious and their minds must be investigated further. His students began conducting research on animals, and the field he called “cognitive ethology” grew from there.
The idea was controversial at the time, but today there is consensus among those who study consciousness that birds and mammals can have sentience. Although there are some extreme skeptics, there is also a consensus that fish feel pain, which may be enough to show sentience. The jury is still out on insects and likely will be for some time, but our understanding of them is changing.
“Social insects have traditionally been thought to be driven entirely by instinct: they can build complex nests and efficiently allocate labor through innate behavior, but they are thought to be stupid as individuals, with complexity manifesting only at the group level,” Lars writes Chitka, co-author of the study and author of The Mind of a Bee, in the Washington Post. “But there is considerable evidence that bees have an internal world of thought – that they don’t just respond to stimuli with fixed responses.”
Much of the debate surrounding sentience centers around the neocortex, the part of the mammalian brain that processes language, cognition, and more, and which most neuroscientists believe gives rise to consciousness. Crump says birds don’t have a neocortex, but a structure in their brains, the dorsal pallium, is similar, and scientists think that’s where avian consciousness would reside.
Fish also lack this brain structure, but over the past two decades, researchers have come to believe that fish probably experience pain in the telencephalon region of the brain, which receives activity from their nociceptors—sensory receptors that identify and respond to noxious stimuli. We can better understand insect life through such discoveries, but it will be difficult to determine whether certain types of insects are sentient or not, let alone all insects.
Much of the current focus of insect researchers is simply to understand what the biological markers of sensitivity are, although the demonstrated ability to make motivational trade-offs, as Gibbons’ bees did, is one of them.
The study builds on our understanding of insects’ ability to feel pain, but does not provide definitive proof that bees or other insect species are sentient. However, using the precautionary principle—the idea that we should err on the side of harm minimization in the face of limited information and uncertainty—let’s assume they are. Should this change the way we treat them?
Bees and other insects can feel pain. Now what?
Debating whether insects are sentient may seem frivolous given how far removed they feel from mammals, let alone humans. But any past debate about who deserves moral attention and how wide our circle of concern should be has seemed frivolous to some. If only a small fraction of the 10 quintillion insects currently alive can feel pain, some changes may be necessary.
In light of this research, the most sensible place to start is with beekeeping. According to Jason Shucraft, a former member of the research group Rethink Priorities (he is now with the grant-making foundation Open Philanthropy), the trillion or so bees managed globally for their honey may suffer from a variety of threats: exposure to pesticides, poor feeding, disease, long-distance transport, invasive hive inspections and honey collection. These factors are associated with colony collapse disorder, but they can be improved through better management.
Many cultures around the world have long eaten insects, but recent years have seen an increase in the factory farming of insects – mainly to supply food for factory-farmed chickens and fish, rather than for direct human consumption. It’s an emerging trend we’d like to think twice about.
An employee places larvae in a sorting oven at the Ynsect insect farm in Dole, France. Cyril Marcilhacy/Bloomberg via Getty Images
If we source more protein from insect farms instead of cattle, pig and chicken farms, that could be a win for human health. But if commonly farmed insects such as crickets and mealworms can feel pain, it could be a moral disaster orders of magnitude worse than animal agriculture, given the astronomical number of insects that would need to be raised to replace the more than 70 billion terrestrial ones animals raised worldwide each year.
We can find ways to live more humanely with insects, such as reducing the use of insecticides at home and on farms. Politicians may one day consider protecting insects by law. Earlier this year, the UK Parliament passed the Animal Welfare (Sensitivity) Bill,…
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