A new paper was published in Animal Cognition today. The paper, authored by Filip Turza and Krzysztof Miler, described how injury and the following decrease in life expectancy affect decision-making in ants.
Formica cinerea ants, which are the study model, are highly territorial and often engage in fights with co-existing species. As a result of their aggression, workers suffer various types of injuries. These injuries lead to infection and pathologies, which is something that decreases the life expectancy of workers.
Photo: Krzysztof Miler. The F. cinerea ants form large multi-nest colonies and can be found in the Błędowska Desert, where they co-exist with many other species of ants.
The authors checked how intact and injured workers differ in their propensities for two types of risky behaviors: aggression and rescue. Their results showed that soon-to-die ants change only their rescue behavior. This likely reflects that the ant colony always needs its workers to be highly aggressive. In turn, interactions between nestmates within a colony likely change with the health status of its workers.
Check out the paper here (open access).
Photo: Filip Turza. An ant takes an interest in a trapped nestmate (immobilized by a snare) and tries to rescue the nestmate by pulling at one of its legs.
Rescue behavior is a type of altruism. In ants, it occurs in many species and in various contexts. However, the mechanisms of this behavior and factors that affect its occurrence need much more research. You can learn more about this fascinating behavior from a recent review by the same authors, here. The review provides a comprehensive overview of the intriguing ways in which ants come to the aid of their imperiled nestmates.