The influence of allogrooming behavior on individual innate immunity in the subterranean termite reticulitermes chinensis (Isoptera: Rhinotermitidae)

Abstract

Insect societies have evolved a series of disease defenses against pathogens, including social sanitary behavior and individual innate immunity. However, whether sanitary behavior can affect individual innate immunity remains unknown. Here, we exposed the termite Reticulitermes chinensis Snyder to the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin(Ascomycota: Hypocreales), and then measured their allogrooming behavior, conidia load, infection mortality, antifungal activity and immune gene expressions. Our results showed that most of the fungal conidia were fast removed from the cuticles of the grouped termites by intensive allogrooming behavior, resulting in low mortality. The antifungal activity and immune gene expressions (termicin and transferrin) in grouped exposed termites were significantly lower than those in single exposed termite but not significantly different from those in unexposed treatments. These results suggest that allogrooming behavior can fast remove fungal conidia from termite cuticles and then decrease their physiological investment in individual innate immunity.