This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Signalling helps connects different organisms in the biosphere. This research note describes the possible concentration-dependent odour mediated attraction of flies to stationary phase aerobic liquid cultures of Bacillus subtilis NRS-762 cultivated on an open orbital shaker at 25 oC. Greater odour pungency correlated with more intense “foraging” attempts, which suggested the compounds’ possible behaviour modifying effects. Additionally, co-occurrence of optical density decline and increase in odour pungency suggested volatile compound(s) secretion might be a cell survival response mediated by a cell density-based signalling mechanism. Flies were not attracted to odourous stationary phase cultures of other common bacteria (Escherichia coli DH5α, Pseudomonas aeruginosa PRD-10, and Pseudomonas protegens Pf-5, which suggested species-specificity of the volatile compound(s)). Altogether, volatile compound(s) might serve as interkingdom messengers to enlist flies for dispersing B. subtilis to habitats with more favourable conditions in coping with possible irreversible decline in habitability, and operate in parallel with other in situ mechanisms such as cannibalism and sporulation that help B. subtilis ride out short- and long-term environmental fluctuations, respectively. Interested researchers are invited to build upon the preliminary findings.