Studies on the volatiles composition of stored sheep wool, and attractancy toward Aedes aegypti mosquitoes

Authors: TSIKOLIA, MAIA - European Biological Control Laboratory (EBCL); Tabanca, Nurhayat; Kline, Daniel - Dan; DEMIRCI, BETUL - Anadolu Universtiy; YANG, LIU - University Of Florida; Linthicum, Kenneth - Ken; BLOOMQUIST, JEFFREY - University Of Florida; BERNIER, ULRICH - Retired ARS Employee

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2022
Publication Date: 2/18/2022
Citation: Tsikolia, M., Tabanca, N., Kline, D.L., Demirci, B., Yang, L., Linthicum, K., Bloomquist, J.R., Bernier, U.R. 2022. Studies on the volatiles composition of stored sheep wool, and attractancy toward Aedes aegypti mosquitoes. Insects. 13(2):1-9. https://doi.org/10.3390/insects13020208.
DOI: https://doi.org/10.3390/insects13020208

Interpretive Summary: To discover new natural tools for control of insects stored sheep wool was investigated for attractancy against mosquitoes. The compounds that emanated from the wool were collected. A total of 52 compounds were detected; many of them known to have mosquito attractant activity against various species. The most abundant compound in the sheep wool hydrodistillate was not attractive for female adult Aedes aegypti mosquitoes in small-scale lab evaluations. Comparative evaluations of raw sheep wool in two large screened outdoor cages each with the bait setup, and equipped with CDC trap, revealed the setup with vibrated sheep wool was the best attractant for female adult Ae. aegypti mosquitoes compared to the setups without wool or not vibrated. It was concluded that sheep wool, as easily available, affordable, and environment friendly material, could be considered as potential tool to be used in the dynamic bait setups for mosquito management and surveillance.

Technical Abstract: To discover new natural tools for insect management commercially available stored sheep wool was investigated for attractancy against female adult Aedes aegypti mosquitoes. The volatiles from sheep wool were collected by various techniques of headspace (HS) extractions and hydrodistillation. These extracts were analyzed using gas chromatography–mass spectrometry (GC-MS) and gas chromatography– the flame ionization detector (GC-FID) coupled with GC-MS. 52 Volatile compounds were detected, many of them known with their mosquito attractant activity. Seven compounds were not previously reported in sheep products. The volatile compositions of the extracts varied significantly across the collections depending on the extraction techniques or types of fibers applied. The hydrodistillate mainly contained thialdine detected by both spectrometry techniques; in HS- Hayesep-Q collection, by GC-MS: alkanes, and, by GC-FID/GC-MS: alcohols were identified as the main components. In HS-SPME collections, by GC-FID/GC-MS: alcohols and aldehydes were identified as the main components using polydimethylsiloxane/divinylbenzene (PDMS/DVB), and carbon-polydimethylsiloxane (C/PDMS), while ionol - using polydimethylsiloxane (PDMS) absorbent. In bioassays with glass tubes the sheep wool hydrodistillate and its main component, thialdine, did not show any significant attractant activity against female adult Ae. aegypti mosquitoes. Bioassays in two large screened outdoor cages, each equipped with CDC trap and the various bait setups with Vortex apparatus, revealed that vibrating wool significantly improved mosquito catches compared to the setups without wool or with wool but not vibrating. We assume that during vibration the wool fiber intensively releases volatiles that are not released as easily at the static conditions. Sheep wool is readily available, affordable, and environment-friendly material. It should have potential to be used as a mosquito management and surveillance component in the dynamic bait setups.