Bioassay-Guided Semiochemical Discovery in Volatile-Mediated Specialized Plant-Pollinator Interactions with a Practical Guide to Fast-Track Progress

More than 85% of all flowering plants depend on animals for pollination, with floral olfactory and visual cues typically responsible for the long-distance attraction of potential pollinators. The idea of bioassay-guided chemical discovery has a surprisingly long history. In tests with Ophrys pollinators, both bees and wasps, B. Kullenberg quickly abandoned early trials with multi-choice bioassays to avoid the risk of confusion of the dummies by the insects. The earlier work of Kullenberg set the stage for the two complementary bioassay designs used in studies of Ophrys: dual-choice bioassays, and consecutive single bioassays including controls. While floral volatiles are expected to play key roles in securing specific pollinator attraction in many cases of pollination by deception and mimicry, surprisingly the chemistry of the interactions is poorly understood. The experimental approach involves the iterative use of field- and/or laboratory experiments with the pollinator across the entire process of chemical investigation.