title: "Singing in the Tube"--audiovisual assay of plant oil repellent activity against mosquitoes (Culex pipiens).
abstract: Plant essential oils have been suggested as a promising alternative to the established mosquito repellent DEET (N,N-diethyl-meta-toluamide). Searching for an assay with generally available equipment, we designed a new audiovisual assay of repellent activity against mosquitoes "Singing in the Tube," testing single mosquitoes in Drosophila cultivation tubes. Statistics with regression analysis should compensate for limitations of simple hardware. The assay was established with female Culex pipiens mosquitoes in 60 experiments, 120-h audio recording, and 2580 estimations of the distance between mosquito sitting position and the chemical. Correlations between parameters of sitting position, flight activity pattern, and flight tone spectrum were analyzed. Regression analysis of psycho-acoustic data of audio files (dB[A]) used a squared and modified sinus function determining wing beat frequency WBF ± SD (357 ± 47 Hz). Application of logistic regression defined the repelling velocity constant. The repelling velocity constant showed a decreasing order of efficiency of plant essential oils: rosemary (Rosmarinus officinalis), eucalyptus (Eucalyptus globulus), lavender (Lavandula angustifolia), citronella (Cymbopogon nardus), tea tree (Melaleuca alternifolia), clove (Syzygium aromaticum), lemon (Citrus limon), patchouli (Pogostemon cablin), DEET, cedar wood (Cedrus atlantica). In conclusion, we suggest (1) disease vector control (e.g., impregnation of bed nets) by eight plant essential oils with repelling velocity superior to DEET, (2) simple mosquito repellency testing in Drosophila cultivation tubes, (3) automated approaches and room surveillance by generally available audio equipment (dB[A]: ISO standard 226), and (4) quantification of repellent activity by parameters of the audiovisual assay defined by correlation and regression analyses.
authors.affiliation: Fachbereich Zellbiologie, Abteilung Pflanzenphysiologie, Universität Salzburg, Salzburg, Austria.
authors.forename: Temitope F
authors.initials: TF
authors.lastname: Adams
authors.affiliation: Division of Biology, School of Science, University of Phayao, Phayao, Thailand.
authors.forename: Chatchawal
authors.initials: C
authors.lastname: Wongchai
authors.affiliation: Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Anchalee
authors.initials: A
authors.lastname: Chaidee
authors.affiliation: Fachbereich Zellbiologie, Abteilung Pflanzenphysiologie, Universität Salzburg, Salzburg, Austria. Wolfgang.Pfeiffer@sbg.ac.at.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Pfeiffer
mesh_terms: D000818:Animals; D001296:Audiovisual Aids; D045783:Clove Oil / Q000494:pharmacology; D003465:Culex / Q000187:drug effects / Q000502:physiology*; D003671:DEET / Q000009:adverse effects / Q000494:pharmacology; D005052:Eucalyptus; D000078122:Eucalyptus Oil; D005260:Female; D005426:Flight, Animal / Q000187:drug effects*; D007302:Insect Repellents / Q000494:pharmacology*; D027523:Lavandula; D039821:Monoterpenes / Q000494:pharmacology; D009822:Oils, Volatile / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology*; D012044:Regression Analysis; D020947:Tea Tree Oil / Q000494:pharmacology; D014828:Vocalization, Animal / Q000187:drug effects*
chemical_list: D045783:Clove Oil; C511306:Eucalyptus terpene oil; D007302:Insect Repellents; D039821:Monoterpenes; D009822:Oils, Volatile; C483659:Patchouliol; D010938:Plant Oils; D003671:DEET; D000078122:Eucalyptus Oil; D020947:Tea Tree Oil; C042023:cedarwood oil; C053775:rosemary oil; C501365:lemon oil; C076730:citronella oil; C045718:lavender oil
keywords: Audiovisual assay of repellent activity against mosquitoes; Culex pipiens; DEET (N,N-diethyl-meta-toluamide); Plant essential oils; Repelling velocity constant defined by logistic regression