Ant larvae regulate worker foraging behavior and ovarian activity in a dose-dependent manner

Abstract

Division of labor in insect societies relies on simple behavioral rules, whereby individual colony members respond to dynamic signals indicating the need for certain tasks to be performed. This in turn gives rise to colony-level phenotypes. However, empirical studies quantifying colony-level signal-response dynamics are lacking. Here, we make use of the unusual biology and experimental amenability of the queenless clonal raider ant Cerapachys biroi to jointly quantify the behavioral and physiological responses of workers to a social signal emitted by larvae. Using automated behavioral quantification and oocyte size measurements in colonies of different sizes and with different worker-to-larvae ratios, we show that the workers in a colony respond to larvae by increasing foraging activity and inhibiting ovarian activation in a progressive manner and that these responses are stronger in smaller colonies. This work adds to our knowledge of the processes that link plastic individual behavioral/physiological responses to colony-level phenotypes in social insect colonies.