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.

Foraging niche separation of social wasps in an invaded area: Implications for their management

“…Lures used were comprised by compounds found to be attractive by Unelius et al (), which were purchased (all of ≥98% purity) from Aldrich/SAFC. These compounds were (a) putative wasp pheromone heptyl butanoate, CAS nr: 5870‐93‐9 (Buteler et al, ; Unelius et al, ); (b) from fermented brown sugar: 3‐methylbut‐1‐yl acetate, CAS nr: 123‐92‐2, 2‐methyl‐1‐butanol, CAS nr: 137‐32‐6 (Unelius et al, ); (c) from beech forest honeydew (Brown, El‐Sayed, Unelius, Beggs, & Suckling, ): methyl phenylacetate, CAS nr: 101‐41‐7; (d) from green‐lipped mussel: 1‐octen‐3‐ol, CAS nr: 3391‐86‐4, 3‐octanone, CAS Number: 106‐68‐3 (Unelius et al, ); compounds with stereocenters were tested as racemates.…”

“…Aldrich/SAFC. These compounds were (a) putative wasp pheromone heptyl butanoate, CAS nr: 5870-93-9(Buteler et al, 2018;Unelius et al, 2014); (b) from fermented brown sugar: 3-methylbut-1-yl acetate, CAS nr: 123-92-2, 2-methyl-1-butanol, CAS nr: 137-32-6; (c) from beech forest honeydew(Brown, El-Sayed, Unelius, Beggs, & Suckling, 2015): methyl phenylacetate, CAS nr: 101-41-7;…”

Volatile profile of Calycanthus occidentalis achenes and evidence for a diverse range of semiochemicals for vespicochory by pestiferous Vespula pensylvanica

“…Indeed, V. pensylvanica were shown to be attracted to the primary alcohols 2-methyl-1-butanol, 3-methyl-1butanol, and 2-phenylethanol, volatiles produced by fungal colonies of Aureobasidium pullulans [18]. Moreover, a relatively complex mixture of volatiles from the honeydew of insects was shown to attract V. vulgaris [17]. The authors of this study [17] also demonstrated wasp attraction to simpler blends including aromatics, an aldehyde, a secondary alcohol, and a primary alcohol.…”

“…Other semiochemicals of vespids are well documented and include commercially available traps (e.g., Rescue! ® ) containing heptyl butyrate [15,16], kairomones from insect-produced honeydew [17], fungal-produced volatiles [18], odors from cooked meats [19], and combining heptyl butyrate with chicken extract [20], among others. Longchain cuticular hydrocarbons similar to those extracted from elaiosomes [14] have also been extracted from the bodies of species of yellowjackets, including V. pensylvanica [21].…”

Field Method for Testing Repellency of an Icaridin-Containing Skin Lotion against Vespid Wasps

“…Control by baiting may be considered as a lesser evil, but it works only if people stay in the neighborhood of the trap. Recent studies of several essential oils and single volatiles demonstrate their repellent effects against vespids [4,5], but some volatiles can attract vespids [6,7]. Such chemicals may be integrated in a “push-pull” strategy that combines repellents around people, and attractants at some distance from them, to trap the vespids [8].…”