The orchids, Epipactis helleborine and E. purpurata emit green-leaf volatiles (GLV’s) attractive to their pollinators, Vespula wasps. E. helleborine emits the same GLV chemicals as cabbage leaves (Brassica oleracea var. capitata) that have been damaged by Large White (Pieris brassicae) caterpillars. These caterpillars are important prey items for the wasps which suggests chemical mimicry on behalf of the orchid.

[I’d counter that cabbage, with its attendant caterpillars, is a recent development arising from human husbandry. Cabbage itself was a coastal plant; other members of the cabbage family rarely support more than single caterpillars. During the orchid’s pre-human evolution, wasps would have fed on a wide range of species, probably dominated by tree caterpillars early in the season, followed by Vanessids on Nettles in riverside habitats during the orchid flowering season.]