Location: Food and Feed Safety ResearchTitle: Interkingdom responses of flies to bacteria mediated by fly physiology and bacterial quorum sensing Author
|Crippen, Tawni - Tc|
Submitted to: Animal Behaviour
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2012
Publication Date: 12/3/2012
Publication URL: http://handle.nal.usda.gov/10113/57306
Citation: Tomberlin, J.K., Crippen, T.L., Tarone, A.M., Singh, B., Adams, K., Rezenom, Y.H., Benbow, M.E., Flores, M., Longnecker, M., Pechal, J.L., Russell, D.H., Beier, R.C., Wood, T.K. 2012. Interkingdom responses of flies to bacteria mediated by fly physiology and bacterial quorum sensing. Animal Behaviour. 84:1449-1456. Interpretive Summary: Blow flies use dead and decaying carcasses for food, egg laying, and maggot developmental sites. They can and do pick up and spread bacterial pathogens from carcasses. One of the factors which affects an insect’s ability to locate a carcass is the smelling of odors produced by chemical compounds released from the carcass. We theorized that some of these odors are produced by bacteria found on the carcass and that these same chemicals are used by the bacteria for their own communication. Responses to bacterial odors were measured in blow flies of different sexes and ages, and reared on different diets. The bacteria used were altered to affect their swarming ability, which is partially controlled by these chemicals. Results show that the blow fly’s age and diet influences its behavior and that the fly uses these chemicals to locate a carcass. These results have broad applications since it appears that blow flies may interact with bacteria through the bacteria’s own chemical communication pathways. Characterization of such pathways will lead to the development of attractants and behavioral modifiers for flies to reduce the dispersal of pathogenic bacteria from animal production facilities.
Technical Abstract: Insect location and utilization of a resource is influenced by a host of variables, including nutrients acquired prior to encountering a stimulus and age of the individual. For the carrion system, we hypothesized the volatiles to which primary colonizers such as blow flies respond are the same signaling molecules produced and utilized for quorum sensing by bacteria found on the resource. Freshly emerged Lucilia sericata were provided different diets (blood or powdered milk) and their behavior assessed in a dual choice assay based on sex and ovarian status of 7-day-old or 14-day-old adults. Their preference between wild type Proteus mirabilis that is able to swarm (a quorum sensing response), or mutated (by transposon mutagenesis) P. mirabilis, which is unable to swarm was determined. In most instances, fly sex did not significantly influence their response. Age and diet appear to be regulating fly motivation and preference. Seven-day-old flies provided blood or powdered milk had a significantly greater probability (P) of responding to the wild type rather than mutant. However, the percentage of flies to respond was 85% less for those milk- rather than blood-fed. Flies fed blood oviposited while those milk-fed did not, and oviposition occurred predominately on the wild type for the 7-day-old and the mutant for the 14-day-old. Results demonstrate that the mechanism used by L. sericata for detecting a resource can be associated with bacterial quorum sensing and that the insect physiological state influences that response. We also identified several differences in volatile compounds produced by the bacteria which could explain blow fly response.