Comparative olfactory and behavioural responses of ant species to streptomyces bacterial volatiles

Actinomycetes bacteria, notably, the Streptomyces genus, has gained significant attention due to their pharmaceutical, agricultural, and medicinal use. There is a growing interest with how insects respond to these volatile microbial metabolites from both an evolutionary standpoint and for practical purposes. Understanding the interaction between insects and microbial metabolites may provide advancements towards more sustainable pest management. This study investigated the behavioural and electrophysiological responses of female worker ants, Lasius alienus, Camponotus pennsylvanicus, and Formica integra as well as male Formica integra ants. Electrophysiological responses to commonly produced Streptomyces volatiles were assessed using gas chromatography-electroantennographic detection. Aldehydes had significantly different electrophysiological responses compared to other stimuli within a species, however, few stimuli showed significant differences in sensitivity when compared among species. Overall electrophysiological responses of Lasius alienus was higher compared to other female species, however, was not found to be significant. Two-choice bioassays were used to determine attraction or repellence towards an industrial stain of Streptomyces coelicolor (strain M145) versus the same strain with a geosmin-production knockout (strain J3001). There was no evidence of significant attraction or repulsion to selected strains among species tested. Future work investigating the role of microbial metabolites in nest making and foraging activity in ants may prove beneficial for the development of pest management strategies. Particularly, the role of geosmin as an attractant or repellent as it is a common volatile produced by microbes and fungi.