Skip to main content
ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #276288
Title: Volatile emissions from an epiphytic fungus are semiochemicals for eusocial wasps

Author
item Davis, Thomas
item BOUNDY-MILLS, KYRIA - University Of California
item Landolt, Peter

Submitted to: The ISME Journal: Multidisciplinary Journal of Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2012
Publication Date: 10/25/2012
Citation: Davis, T.S., Boundy-Mills, K., Landolt, P.J. 2012. Volatile emissions from an epiphytic fungus are semiochemicals for eusocial wasps. The ISME Journal: Multidisciplinary Journal of Microbial Ecology. 64:1056-1063.

Interpretive Summary: Social wasps are a stinging hazard for farm workers that harvest fruit and these wasps also cause direct feeding damage to cherries, pears, and grapes. Chemical attractants are of use against these wasps as lures for traps and baits. Researchers at the USDA-ARS Yakima Agricultural Research Laboratory with scientists at the University of California, Davis, CA, surveyed yellowjacket wasp attraction responses to a common yeast found on fruits and foliage and to volatile compounds produced by the same yeasts. Two pest species of yellowjacket, the western yellowjacket and the German yellowjacket, were attracted to colonies of the yeast, and to chemicals produced by the yeast. This work explains the origin of stinging wasp attraction to chemicals used in lures for traps, and suggests additional chemicals that might be useful for detecting and managing invasive and pest species.

Technical Abstract: Here we report evidence for a functional symbiosis between a ubiquitous epiphytic fungus and two eusocial hymenopterans. We tested the hypothesis that volatiles emitted by an epiphytic fungus are wasp semiochemicals. We isolated the fungus Aureobasidium pullalans from apple pomes and quantified volatile compounds emitted by fungal colonies. We tested the attractiveness of fungal colonies and fungal volatiles to social wasps (Vespula spp.) in the field. Three important findings emerged: 1) traps baited with A. pullalans caught 2750% more wasps on average than unbaited control traps; 2) the major headspace volatiles emitted by A. pullalans were 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-phenylethyl alcohol; and 3) a synthetic blend of fungal volatile compounds attracted 4933% more wasps on average than unbaited controls. Wasps were most attracted to the volatile 2-methyl-1-butanol. The primary wasp species attracted to fungal volatiles were the western yellowjacket (Vespula pensylvanica) and the German yellowjacket (V. germanica), and we found both species externally vectoring A. pullalans. This is the first experimental evidence that eusocial wasps orient to microbial volatile emissions. Our work implicates epiphytic fungi as an important component in the community ecology of some eusocial wasps, and we suggest that fungal emissions signal suitable nutrient sources to foraging wasps.