Learning a Behavioral Sequence: An Accessible Challenge for Myrmica sabuleti Workers?

We aimed to investigate on the ability of the ant Myrmica sabuleti in learning a behavioral sequence. We created two sequences consisting in navigating through five successive elements on the way to the nest, and tried to learn them to foragers. They could progressively learn a sequence for which the different steps were presented in a backward order. Doing so, each exhibited step leaded to an already known step and thus to the reward consisting in finally entering the nest. The ants were unable to learn a behavioral sequence for which the different steps were presented in a forward order. With the latter kind of presentation, each exhibited step leaded to an unknown step and thus not to the reward. Myrmica sabuleti ants learned thus a behavioral sequence when going through operant conditioning and not by using the response to a step as a motivation for responding to the next step. On the contrary, highly evolved mammals (monkey, humans) and birds (parrots) can learn a behavioral sequence according to a backward or a forward chaining, or by being presented with the entire sequence and memorizing, then imitating the different steps.