Meeting Abstract

P3-28   -   Mechanical extractions of plant material in mineral oil provide ethologically relevant odor stimuli Edwards, A; Sprayberry, JDH*; Muhlenberg College; Muhlenberg College jordannasprayberry@muhlenberg.edu

Odor information is one of the sensory cues provided by flowers for their pollinators. Bumblebees are known to use floral-odor information in their foraging decisions and are capable of using floral-odors to navigate to novel odor sources. Not all odors are created equal – floral odors can have unique structural compositions correlated with their principle pollinators; implying that odor structure is relevant ethological information for pollinators. Therefore, it is desirable to use ecologically relevant odor stimuli in experiments investigating the role floral-odor in foraging. Given that commercial essential oils do not always have the same structure as the plant material they are derived from, and that commercial oils are not made many ecologically relevant species, we sought to develop a reliable odor stimulus from plant material. These experiments tested the ability of the bumblebee Bombus impatiens to discriminate between commercial peppermint essential oil (used in published odor-learning studies), lab-distilled peppermint essential oil, mechanically-extracted peppermint oil (suspended in mineral oil), and peppermint plant material. Bumblebees were able to discriminate between plant material and both types of essential oil, but did not easily differentiate between plant material and mechanical extract. SPME-GCMS analysis indicates that mechanical extracts are stable for prolonged periods when stored at cold temperatures. This allows preparation of odor stimuli when relevant species are in bloom that can be used in lab experiments year-round. The efficacy of mechanical extraction as an odor stimulus was confirmed with wild-bergamot odor preparations. However, plants that produce novel odor compounds when damaged may not be good candidates for this method.