Pollen removal changes floral scent of buzz-pollinated Solanum flowers

Abstract

Floral scent influences the recruitment, learning, and behaviour of floral visitors. Variation in floral scent can provide cues of the amount of reward available or whether a flower has been visited recently and may be particularly important in species with visually concealed rewards. In many buzz-pollinated flowers, tubular anthers opening via small apical pores (poricidal anthers) visually conceal pollen and appear similar regardless of pollen quantity within the anther. We investigated whether pollen removal changes scent composition and emission rate in seven taxa of buzz-pollinated Solanum (Solanaceae). We found that pollen removal reduced overall scent emission. Moreover, in S. lumholtzianum, pollen removal reduced the emission of specific compounds (linalool and farnesol). Our findings suggest that scent could be used as a cue by visitors of buzz-pollinated flowers as it contains information on potential pollen availability.