Metabolic division of labor in social insects

Social insects are known for reproductive and behavioral division of labor, but little attention has been paid to metabolic forms of division of labor. Metabolic division of labor is the partitioning of complementary metabolic tasks between individuals, and it is widespread in social insects. We define two forms of metabolic division of labor, homosynergetic and heterosynergetic, we pinpoint trophallaxis, trophic eggs, and cannibalism as the primary transfers underlying the homosynergetic form and discuss their evolution. We argue that homosynergetic metabolic division of labor underpins fundamental aspects of colony physiology and may be a necessary feature of superorganismal systems, impacting many life history traits. Investigating metabolic division of labor is necessary to understand major evolutionary transition(s) to superorganismality in social insects. •Homosynergetic metabolic division of labor is widespread but understudied in social insects.•Metabolic division of labor requires the transfer of processed metabolites between nestmates.•Trophallaxis, trophic eggs, and cannibalism are the main modes of transfer used by social insects.•Metabolic interdependency reinforces, entrenches, and unifies the superorganism.•Social insects are an excellent system to study networked metabolism.