Beyond temporal-polyethism: division of labor in the eusocial bee Melipona marginata

Abstract

Division of labor plays a fundamental role in colony organization in social insects. In many species, division of labor is based on temporal behavioral castes, whereby workers change tasks as they age. However, division of labor remains relatively poorly understood in the large and diverse group of stingless bees (Meliponini), particularly in the largest and economically important genus Melipona. Recent research suggests that stingless bees can differ considerably from other eusocial bees in their division of labor. Here, we studied the lifetime task performance of individually marked workers of the Brazilian species Melipona marginata. We found that colony organization in M. marginata is characterized by temporal castes and a tendency for elitism, i.e. positive performance correlations across the major tasks. Additionally, we also found that individual workers differ considerably in their work profiles and overall effort. A cluster analysis found evidence for a group of workers that are particularly active in wax manipulation and cell building, two behaviors that are linked to the provisioning and oviposition process (POP). Remarkably, the majority of bees (59%) were never seen foraging and non-foragers were characterized by fewer trophallaxes and less grooming during their lifetime. Bees that did forage often specialized in collecting particular resources, e.g. pollen and mud collectors. In summary, our results suggest that the colony organization in M. marginata is complex and includes temporal castes, elitism across some tasks and specialization in others.