Social aphids: emerging model for studying insect sociality.

Sociality is also evolved in parthenogenetic herbivorous hemipteran aphids, encompassing species with complex life history traits and significant social diversity. Owing to their interesting biological characteristics comparing to other social insect groups, social aphids can be a good model for studying insect sociality. Here, we review the species, behavior, and trait diversity of social aphids, and present recent findings on environmental, physiological, and molecular regulations of caste differentiation and behavior in social aphids. We propose the unique value of social aphids in investigating the evolution and mechanisms of insect sociality as well as future research directions using the social aphid model, including social evolution, caste differentiation, behavioral polymorphism, morphological plasticity, physical mechanics, and interspecific interactions.