Pheromone deposition in L. niger - a measure of perceived value
The ant Lasius niger deposits trail pheromone in order to bring nestmates to valuable resources, such as food. The better the food - specifically, the more valuable the ant perceives the food to be - the more likely she is to deposit pheromone.
Pheromone deposition is easily seen - the ant pauses briefly, and presses her abdomen onto the ground.
Behavioural Economics in Insects
While traditional economics assumes rational behaviour, behavioural economics has robustly demonstrated that this is not always true. Predictable deviations from economic rationality emerge due to how we perceive the world, how we calculate value, and the mental shortcuts ('heuristics') we use.
Work from the ACElab and elsewhere is showing that the same holds true for insects as well. For example:
Ants don't like to gamble for food, because of how they perceive relative sweetness.
Bees and ants can be disappointed or very happy about receiving a moderate reward, depending on whether they were expecting a good or a poor one.
Ants prefer food which they worked hard for.
"Liking", but not "wanting" in ants is affected by whether the food is offered as many small rewards or one big reward.
Key to much of our work is quantifying how much insects value things. A powerful approach is training animals two two or more options, each associated with a smell, and then afterwards asking them which smell they prefer (for example, on a Y-maze for ants). We can also tell how much an insect likes a reward by its feeding behaviour.
Ants offer another source of insight into value perception: pheromone deposition. They deposit more pheromone for things they perceive as higher value - look on the right to see what we mean. Interestingly, this might tell us something subtly different from choice: it might tell us what ants "like", which is potentially different from what they choose, i.e. "want".