title: Invasive Vespula Wasps Utilize Kairomones to Exploit Honeydew Produced by Sooty Scale Insects, Ultracoelostoma.
abstract: Vespula wasps are widely distributed invasive alien species that are able to reach high population densities in the 1.2 M ha of beech forests (Fuscospora spp.) of New Zealand's South Island. These endemic temperate forests have an abundance of carbohydrate-rich honeydew produced by native scale insects (Ultracoelostoma spp.). A characteristic aroma is associated with the honeydew in beech forests, which we hypothesized is the signal used by wasps to harvest the vast resources previously exploited by birds and other insects. Volatile collections were taken of black beech tree trunks with honeydew and sooty mold present, and analyzed with a gas chromatograph-mass spectrometer. Eleven compounds (benzaldehyde, benzyl alcohol, 2-phenylethyl acetate, 2-phenylethanol, phenylacetaldehyde, methyl 2-phenylacetate, ethyl 2-phenylacetate, methyl salicylate, n-octanol, octan-3-ol, and 1-octen-3-ol) were positively identified from the headspace, and were shown to elicit an electrophysiological response from Vespula vulgaris worker antennae by using electroantennography (EAG). Field trials with delta traps individually baited with these compounds confirmed wasp attraction to 8 of the 11 compounds tested, with 2-phenylethyl acetate, methyl salicylate, and octan-3-ol capturing the same numbers of wasps as the control. In later trials, attraction to a 1:1 blend of benzaldehyde and n-octanol was significantly higher (45%) than to any other treatment. Many of the chemicals identified are known to be associated with fermenting sugars, or with fungal aroma. Benzaldehyde and n-octanol are common compounds produced by many different species in nature. The ability to respond to generic signals emanating from sugar resources is likely to contribute to the success of V. vulgaris as an invasive species.
authors.affiliation: Biosecurity Group, The New Zealand Institute for Plant & Food Research Ltd, Canterbury Research Centre, Lincoln, 7608, New Zealand. bob3brown@yahoo.com.|School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand. bob3brown@yahoo.com.|Biodiversity and Conservation Team, Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand. bob3brown@yahoo.com.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Brown
authors.affiliation: Biosecurity Group, The New Zealand Institute for Plant & Food Research Ltd, Canterbury Research Centre, Lincoln, 7608, New Zealand.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: El-Sayed
authors.affiliation: Biosecurity Group, The New Zealand Institute for Plant & Food Research Ltd, Canterbury Research Centre, Lincoln, 7608, New Zealand.|Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, SE-391 82, Sweden.
authors.forename: C Rikard
authors.initials: CR
authors.lastname: Unelius
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Beggs
authors.affiliation: Biosecurity Group, The New Zealand Institute for Plant & Food Research Ltd, Canterbury Research Centre, Lincoln, 7608, New Zealand.|School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: David M
authors.initials: DM
authors.lastname: Suckling
mesh_terms: D000818:Animals; D020387:Food Chain; D006430:Hemiptera / Q000502:physiology*; D058865:Introduced Species; D009520:New Zealand; D009812:Odorants; D055549:Volatile Organic Compounds / Q000378:metabolism*; D014863:Wasps / Q000502:physiology*
chemical_list: D055549:Volatile Organic Compounds
keywords: Benzaldehyde; Feeding attractants; Fuscospora and honeydew beech forest; Hemiptera; Invasive pest; Margarodidae; Vespula vulgaris; n-octanol