Origins of Aminergic Regulation of Behavior in Complex Insect Social Systems

Abstract

Neuromodulators are conserved across insect taxa, but how biogenic amines and their receptors in ancestral solitary forms have been co-opted to control behaviors in derived socially complex species is largely unknown. Here we explore patterns associated with the functions of octopamine (OA), serotonin (5-HT) and dopamine (DA) in solitary ancestral insects and their derived functions in eusocial ants, bees, wasps and termites. Synthesizing current findings that reveal potential ancestral roles of monoamines in insects, we identify physiological processes and conserved behaviors under aminergic control, consider how biogenic amines may have evolved to modulate complex social behavior, and present focal research areas that warrant further study.

Keywords: biogenic amines; collective intelligence; eusocial; neuromodulation; social brain evolution.

Figure 1

Phylogenetic relationship of biogenic amine function across the insects. Behaviors are organized into eight categories (activity, aggression, development, sensory integration, nutrition, reproduction, sensory motor, social function). The overarching trend of the behavioral effects for octopamine (OA), serotonin (5-HT) and dopamine (DA) in each of these categories is represented in the corresponding boxes. Within the phylogenetic tree, black lines indicate solitary/presocial species and orange lines indicate the evolution of eusociality. Insect images are from PhyloPic. http://phylopic.org