Commitment time depends on both current and target nest value in Temnothorax albipennis ant colonies

Abstract

Animals gather noisy information about the world and then process it to trigger appropriate behavioural responses. To identify the best action to take, both the costs and benefits associated with each action should be taken into account. Social insects are known to be good at solving such trade-offs, since they rely on the ‘wisdom of the crowd’. In other words, by pooling the decisions of many individuals, they can reach an optimal collective decision. However, this process can lead to the assumption that adaptive flexibility in decision-making resides entirely at the colony level, whereas decision-making by individuals is constrained by their limited cognitive capacities. Here, we show that ant colonies are able to respond flexibly and adaptively to their environment when making decisions and that this feature is accomplished by individuals also showing such flexibility. We presented Temnothorax albipennis colonies with the opportunity to move to a better home and measured how emigration dynamics were affected by varying the value of both current and target nests. Colonies take less time to commit to a new nest when the value difference between current and target nest is bigger, i.e. greater benefit. Furthermore, this is accomplished by individuals manipulating their recruitment speed either by moving faster or recruiting sooner. This observation indicates that, regardless of the degree of difficulty of the choice, an individual that has sufficient time and information can make good decisions that will ultimately confer its group the ability to solve more complicated dilemmas.