Behavioural responses of Tribolium castaneum (Herbst) to volatiles identified from dry cocoa beans.
New hybrid types of cocoa beans are attractive to insects in storage, however some of the insects feed little, if at all, on these beans compared to those of the traditional type (mixed genotypes). Based on a sniffing test using GCMS, differences in flavour volatiles in these types of beans have been determined and from these, six major volatiles of cocoa beans were selected for olfactometric analysis using a Pettersson olfactometer to determine which of them contributed to the attraction of Tribolium castaneum (Herbst) to the cocoa beans. The behaviour of Tribolium was affected by dose of 2-phenyl ethanol, acetophenone, 3-methyl butyraldehyde, ethyl butyrate, ethyl 3-hydroxybutyrate and butyl 2-methacrylate. Compared to beans of the new hybrid varieties, beans of the traditional type cocoa contained less 3-methylbutyraldehyde but more ethyl butyrate and acetophenone. In future breeding programmes, reducing the amount of acetophenone and ethyl butyrate but increasing the amount of 3-methylbutyraldehyde in cocoa beans may deter Tribolium from feeding on beans in storage.
Jonfia-Essien
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WA
School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, Leicestershire, LE12 5RD, UK.
Alderson
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PG
Tucker
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Linforth
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West
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G
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002099:Cacao / Q000737:chemistry*; D006801:Humans; D007300:Insect Control / Q000379:methods; D009812:Odorants / Q000032:analysis; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D012903:Smell; D014231:Tribolium / Q000187:drug effects / Q000502:physiology
D009822:Oils, Volatile; D010938:Plant Oils