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Annu Rev Entomol

Title:		"Floral isolation, specialized pollination, and pollinator behavior in orchids"
Author(s):		Schiestl FP; Schluter PM;
Address:		"Institute of Systematic Botany, University of Zurich, 8008 Zurich, Switzerland. florian.schiestl@systbot.uzh.ch"
Journal Title:		Annu Rev Entomol
Year:		2009
Volume:		54
Issue:
Page Number:		425 - 446
DOI:		10.1146/annurev.ento.54.110807.090603
ISSN/ISBN:		0066-4170 (Print) 0066-4170 (Linking)
Abstract:		"Floral isolation is a form of prepollination reproductive isolation mediated by floral morphology (morphological isolation) and pollinator behavior (ethological isolation). Here we review mechanisms and evolutionary consequences of floral isolation in various pollination systems. Furthermore, we compare key features of floral isolation, i.e., pollinator sharing and specialization in pollination, in different orchid pollination systems. In orchid pollination, pollinator sharing is generally low, indicating strong floral isolation. The pollinators' motivation to visit flowers (specifically) can be due to both foraging or reproductive behavior. In both types of behavior, innate preferences for floral signals can be quickly overruled by learning. In pollination systems in which reproductive behavior of pollinators triggers flower visits, lower pollinator sharing was evident compared with systems with foraging behavior, probably because pollinators displaying reproductive behavior show higher fidelity in their visitation patterns. Orchids pollinated through reproductive behavior also use fewer pollinators than orchids pollinated through foraging behavior. No association between specialization and pollinator sharing was found. Thus, generalized pollination does not impede floral isolation, as orchids with many pollinators may nonetheless have low pollinator sharing. Specialization in pollination was, however, linked to orchid species richness in our analysis. Flower size, spur, and column morphology are most important for morphological isolation, and floral scent is most important for ethological isolation. These traits may be based on few genes, implying that floral isolation can be brought about by few genes of large effect"
Keywords:		Animals *Appetitive Behavior Flowers/genetics/*physiology Genetic Speciation *Insecta Orchidaceae/genetics/*physiology Phylogeny *Pollination;
Notes:		"MedlineSchiestl, Florian P Schluter, Philipp M eng Meta-Analysis Research Support, Non-U.S. Gov't Review 2008/12/11 Annu Rev Entomol. 2009; 54:425-46. doi: 10.1146/annurev.ento.54.110807.090603"