Bees Show 'Liking' and 'Disliking' Reactions: New Study Suggests Inner Lives for Insects

Understanding Bee Behavior: 'Liking' or 'Disliking'

In a groundbreaking study, researchers from Macquarie University and Southern Medical University in China have captured bumblebee behavior that suggests these insects can experience feelings similar to those observed in mammals. When bees taste sweet solutions, they keep their glossa (or insect tongues) out longer, almost as if they are tasting with pleasure. Conversely, when presented with salty or bitter substances like quinine, the bees show clear signs of aversion by shaking their heads and wiping their mouths.

Methodology and Findings

The study, published in the journal Proceedings of the National Academy of Sciences, involved presenting bumblebees with droplets of different solutions: 60% sugar, 20% sugar, plain water, 5% salt, or quinine (at a concentration of 1 millimolar). Scientists used slow-motion video to document the bees' reactions. Prof Andrew Barron from Macquarie University explains that these behaviors are consistent with what mammals display when they like or dislike something. He states, “Facial expressions are an important window into the internal states of animals.”

When bumblebees taste something good, they reach out their glossa – or insect tongue – for a while afterwards, almost as if they are licking their lips. And when they don’t like something, the insects will shake their heads and wipe their mouths. The researchers observed that bees displayed “post-consumption glossa” after tasting sweet solutions, continuing to lick even after finishing drinking. In contrast, they showed clear distaste for salt or quinine solutions.

Contextual Reactions and Controversies

To ensure their findings were not merely a chemical reflex, the scientists tested responses with 18 colonies under a range of circumstances, including when the bees were heat-stressed, already full, or given doses of different drugs. The bees’ reactions depended on context. For example, heat exposure changed their response to water or salty solutions from neutral or averse reactions to positive. As Prof Barron explains, “It is as if someone had offered you an electrolyte drink. You’d probably go ‘blegh’ most of the time. Unless you’ve just been out on a really, really hot day, and done an enormous run, in which case an electrolyte drink is exactly what your body needs and it tastes fantastic.”

Associate Prof Thomas White from the University of Sydney, who was not involved in the study, commented on the significance of this research. He said, “Research into insect behaviour and sentience is a fast-moving field. What made this study fascinating was its focus on the ‘positive side of life,’ as the vast majority of research investigates negative feelings, such as pain or fear.”

White noted that the picture is increasingly pushing towards a view that insects, or many insects, have some simple capacity to feel the world, not just to assess it and detect it but to actually have a point of view. This challenges people’s intuition about where we might draw the line in the animal kingdom as to what can feel pleasure and pain, hence the kind of ethical and moral responsibilities we have towards those animals.

Prof Barron emphasized, “There’s always been a tension between thinking of insects as animals or some sort of mini robots. This is another step towards showing there's an inner life to being a bee.” The study challenges the traditional view of insects as merely robots and suggests they have some capacity for subjective experience.

Source: The Guardian