Volatiles from Merino fleece evoke antennal and behavioural responses in the Australian sheep blow fly Lucilia cuprina

• Published in: Medical and veterinary entomology 2019-12, Vol.33 (4), p.491-497
• Main Authors: Yan, G., Liu, S., Schlink, A. C., Flematti, G. R., Brodie, B. S., Bohman, B., Greeff, J. C., Vercoe, P. E., Hu, J., Martin, G. B.
• Format: Article
• Language: English
• Subjects: Aldehydes - metabolism; Animal behavior; Animals; Attraction; Calliphoridae; Chemotaxis; Diptera; Diptera - drug effects; Diptera - physiology; Electroantennograms; Female; Gas chromatography; GC‐EAD; Headspace; Lucilia cuprina; Mass spectroscopy; nonanal; octanal; Odorants - analysis; Pheromones - metabolism; semiochemical; Semiochemicals; Sheep; Sheep - metabolism; Solid phase methods; Volatile Organic Compounds - metabolism; Volatiles; Wool; Wool - chemistry
• ISSN: 0269-283X; 1365-2915
• DOI: 10.1111/mve.12383

To identify flystrike‐related volatile compounds in wool from Merino sheep, the attractiveness of wool to Lucilia cuprina Wiedmann (Diptera: Calliphoridae) was examined. First, a selection of wool samples guided by previous knowledge of sheep lines, predicted to be more susceptible or more resistant to flystrike, was tested. The attractiveness of the 10 samples selected was not associated with field susceptibility: two samples from the more resistant line were identified as most attractive and two samples from the more susceptible line were identified as least attractive, based on the behavioural assays with gravid flies. Comparison of the headspace volatiles of these samples, using solid phase microextraction and gas chromatography‐mass spectrometry‐electroantennographic detection, revealed octanal and nonanal to be present in the attractive wool samples that elicited responses from the fly antenna. Furthermore, the two compounds were not present in wool that was least attractive to L. cuprina. In laboratory bioassays, octanal and nonanal evoked antennal and behavioural responses in gravid L. cuprina, thus confirming their potential role as semiochemicals responsible for attracting L. cuprina to Merino sheep. Flystrike is a distressing disease caused by blow flies ovipositing on attractive areas of sheep, with the hatched larvae consequently feeding on sheep tissue. Wool samples from different sheep showed different attractiveness to gravid Lucilia cuprina. Octanal and nonanal were the two compounds present in the attractive wool samples that evoked antennal and behavioural response in gravid Lucilia cuprina.