[PCA] Journal Article: HE EVOLUTION OF FLORAL SCENT AND OLFACTORY PREFERENCES IN POLLINATORS: COEVOLUTION OR PRE-EXISTING BIAS?

[Patricia_DeAngelis at fws.gov]

Thanks to Peter Bernhardt on the Pollinator Listserve for posting this 
thought-provoking article. 

Patricia S. De Angelis, Ph.D.
Botanist, Division of Scientific Authority-US Fish & Wildlife Service
Chair, Medicinal Plant Working Group-Plant Conservation Alliance
4401 N. Fairfax Dr., Suite 110
Arlington, VA  22203
703-358-1708 x1753
FAX: 703-358-2276

Promoting sustainable use and conservation of our native medicinal plants.
<www.nps.gov/plants/medicinal>

THE EVOLUTION OF FLORAL SCENT AND OLFACTORY PREFERENCES IN POLLINATORS: 
COEVOLUTION OR PRE-EXISTING BIAS?
Florian P. Schiestl1,2, Stefan Dötterl3
Evolution 2012:1-14

Coevolution is thought to be a major factor in shaping plant?pollinator 
interactions. Alternatively, plants may have evolved traits that fitted 
pre-existing preferences or morphologies in the pollinators. Here, we test 
these two scenarios in the plant family of Araceae and scarab beetles 
(Coleoptera, Scarabaeidae) as pollinators. We focused on floral volatile 
organic compounds (VOCs) and production/detection of VOCs by scarab 
beetles. We found phylogenetic structure in the production/detection of 
methoxylated aromatics in scarabs, but not plants. Within the plants, most 
of the compounds showed a well-supported pattern of correlated evolution 
with scarab-beetle pollination. In contrast, the scarabs showed no 
correlation between VOC production/detection and visitation to Araceae 
flowers, with the exception of the VOC skatole. Moreover, many VOCs were 
found in nonpollinating beetle groups (e.g., Melolonthinae) that are 
ancestors of pollinating scarabs. Importantly, none of the tested VOCs 
were found to have originated in pollinating taxa. Our analysis indicates 
a Jurassic origin of VOC production/detection in scarabs, but a 
Cretaceous/Paleocene origin of floral VOCs in plants. Therefore, we argue 
against coevolution, instead supporting the scenario of sequential 
evolution of floral VOCs in Araceae driven by pre-existing bias of 
pollinators.

1Institute of Systematic Botany, University of Zu¨ rich, 8008 Zu¨ rich, 
Switzerland 
2 E-mail: florian.schiestl at systbot.uzh.ch
3 Department of Plant Systematics, University of Bayreuth, 95447 Bayreuth, 
Germany

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