Responses of the sheep blowflies Lucilia sericata and L. cuprina to odour and the development of semiochemical baits.

The literature relating to the attraction of the sheep blowflies Lucilia sericata and Lucilia cuprina to their ovine hosts is reviewed. The responses of the two species are similar and different components of the behaviour leading to host location and oviposition appear to involve at least two distinct sets of semiochemical cues. Activation, upwind orientation and landing appear to occur in response to putrefactive sulphur-rich volatiles, originating from bacterial decomposition products. Oviposition is elicited primarily by the presence of decomposition products. Oviposition is elicited primarily by the presence of ammonia-rich compounds; moisture, pheromones and tactile stimuli may also act as oviposition stimuli. There is a pronounced sex difference in the response of Lucilia to semiochemicals with a higher proportion of females attracted than males and a higher proportion of gravid than non-gravid females. While the mechanisms of host location by Lucilia are of intrinsic interest, understanding the responses to semiochemicals is important in the attempt to develop powerful synthetic baits for deployment with the traps or targets used for population sampling or suppression. The literature is discussed with respect to the development of synthetic semiochemical baits.