  The traditional focus of physiological and functional genomic research is on
molecular processes that play out within a single body. In contrast, when
social interactions occur, molecular and behavioral responses in interacting
individuals can lead to physiological processes that are distributed across
multiple individuals. In eusocial insect colonies, such multi-body processes
are tightly integrated, involving social communication mechanisms that regulate
the physiology of colony members. As a result, conserved physiological
mechanisms, for example related to pheromone detection and neural signaling
pathways, are deployed in novel contexts and regulate emergent colony traits
during the evolutionary origin and elaboration of social complexity. Here we
review conceptual frameworks for organismal and colony physiology, and
highlight functional genomic, physiological, and behavioral research exploring
how colony-level traits arise from physical and chemical interactions among
nestmates. We highlight mechanistic work exploring how colony traits arise from
physical and chemical interactions among physiologically-specialized nestmates
of various developmental stages. We consider similarities and differences
between organismal and colony physiology, and make specific predictions based
on a decentralized perspective on the function and evolution of colony traits.
Integrated models of colony physiological function will be useful to address
fundamental questions related to the evolution and ecology of collective
behavior in natural systems.
