Phylogenetic analyses of the proteins involved in encapsulation signaling pathways in ants

Abstract

"One of the major evolutionary transitions is the shift from solitary to social lifestyle, which involved a plethora of behavioral and physiological changes in social entities. Group living has several advantages as the evolution of collective defense mechanisms. It may also affect the individual immune system either due to the efficiency of social immune defenses or because of the high transmission frequency of pathogens. Individual defense consists of the innate and acquired immune components. In insects, there are two signaling pathways (Toll and Jak/Stat) that result in the expression of specific immune genes, which, in their turn, encode peptides, proteins and activate innate immune responses like encapsulation. The main aim of our study was to verify whether transition to eusocial lifestyle is reflected in proteins involved in immune responses. We carried out phylogenetic analyses of 15 proteins involved in encapsulation signaling pathways in ants. We also included four other social insect groups, bees, sweat bees, social wasps, and termites, and three solitary insect groups, as fruit flies, braconid wasps, and megachilid bees. Ants grouped separately from other insect groups in most cases, however, there were some notable exceptions mostly in the case of pattern recognition proteins, probably correlating with differences in potential pathogens. No major differences were revealed though between solitary and social insects with respect to proteins involved in encapsulation. Keywords: eusociality, evolution, immune response, innate immunity, insects, social immunity"