| Title: | Three floral volatiles contribute to differential pollinator attraction in monkeyflowers (Mimulus) |
| Author(s): | Byers KJ; Bradshaw HD; Riffell JA; |
| Address: | "Department of Biology, University of Washington, Seattle, WA 98195-1800, USA" |
| ISSN/ISBN: | 1477-9145 (Electronic) 0022-0949 (Print) 0022-0949 (Linking) |
| Abstract: | "Flowering plants employ a wide variety of signals, including scent, to attract the attention of pollinators. In this study we investigated the role of floral scent in mediating differential attraction between two species of monkeyflowers (Mimulus) reproductively isolated by pollinator preference. The emission rate and chemical identity of floral volatiles differ between the bumblebee-pollinated Mimulus lewisii and the hummingbird-pollinated M. cardinalis. Mimulus lewisii flowers produce an array of volatiles dominated by d-limonene, beta-myrcene and E-beta-ocimene. Of these three monoterpenes, M. cardinalis flowers produce only d-limonene, released at just 0.9% the rate of M. lewisii flowers. Using the Bombus vosnesenskii bumblebee, an important pollinator of M. lewisii, we conducted simultaneous gas chromatography with extracellular recordings in the bumblebee antennal lobe. Results from these experiments revealed that these three monoterpenes evoke significant neural responses, and that a synthetic mixture of the three volatiles evokes the same responses as the natural scent. Furthermore, the neural population shows enhanced responses to the M. lewisii scent over the scent of M. cardinalis. This neural response is reflected in behavior; in two-choice assays, bumblebees investigate artificial flowers scented with M. lewisii more frequently than ones scented with M. cardinalis, and in synthetic mixtures the three monoterpenes are necessary and sufficient to recapitulate responses to the natural scent of M. lewisii. In this system, floral scent alone is sufficient to elicit differential visitation by bumblebees, implying a strong role of scent in the maintenance of reproductive isolation between M. lewisii and M. cardinalis" |
| Keywords: | "Animals Bees/*physiology Behavior, Animal Flowers/chemistry Gas Chromatography-Mass Spectrometry Mimulus/*chemistry Monoterpenes/chemistry/isolation & purification/*pharmacology Pollination Smell Volatilization Antennal lobe Floral scent Insect behavior O;" |
| Notes: | "MedlineByers, Kelsey J R P Bradshaw, H D Jr Riffell, Jeffrey A eng R01 GM088805/GM/NIGMS NIH HHS/ 5R01GM088805/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2013/11/08 J Exp Biol. 2014 Feb 15; 217(Pt 4):614-23. doi: 10.1242/jeb.092213. Epub 2013 Nov 6" |
