Vespidae represents a large and diverse family and comprises both social and solitary wasps that occupy a large array of habitats. Though some are considered nuisance insects, many of the species are also known as insect predators and pollinators. An additional role of select vespid wasps, originally elucidated approximately 30 years ago and gaining in the number of identified wasps, is dispersal of plant reproductive organs (vespicochory). This relationship is considered mutualistic given the long-range dispersal benefit to the diaspore, and the nutritional benefit to the wasps. Long-chain hydrocarbons have been shown to be responsible for attracting wasps to the organs of some diaspores. Recent observations in northern California indicated that yellowjackets (Vespula spp.), particularly western yellowjacket, Vespula pensylvanica, procured and transported diaspores (achenes) from the western spicebush (Calycanthus occidentalis), a riparian shrub endemic to California. Volatile profile analyses of C. occidentalis achenes showed emission of a diverse range of volatile classes. Empirical electrophysiological and trapping studies suggest a composite of odors may stimulate wasp attractancy to the achene.
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