Mechanisms of pathogen recognition in subterranean termites

Termites have behavioral mechanisms including alarm and allogrooming for protection from infection from entomopathogenic fungi such as Metarhizium spp., which they are constant threat of. However, recognition of pathogenic soil fungi by subterranean termites remains a subject requiring further investigation. 

We explored how ergosterol, a component found in fungal cell membranes, influences social immune responses in termites. For this, we exposed groups of termite workers directly to ergosterol as well as to Metarhizium strains with different ergosterol content and observed alarm and allogrooming behaviour.

Workers exposed to ergosterol showed increased allogrooming and alarm whereas workers exposed to Metarhizium strains with reduced ergosterol content showed reduced allogrooming and alarm and increased mortality.

In summary, our study suggests that ergosterol likely plays a role in termite immunity by serving as a recognition cue enhancing the social immune response to combat Metarhizium threats.