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Oecologia

Title:		Post-pollination emission of a repellent compound in a sexually deceptive orchid: a new mechanism for maximising reproductive success?
Author(s):		Schiestl FP; Ayasse M;
Address:		"Department of Evolutionary Biology, Institute of Zoology, Althanstr. 14, 1090, Vienna, Austria"
Journal Title:		Oecologia
Year:		2001
Volume:		20010201
Issue:		4
Page Number:		531 - 534
DOI:		10.1007/s004420000552
ISSN/ISBN:		1432-1939 (Electronic) 0029-8549 (Linking)
Abstract:		"The flowers of the sexually deceptive orchid Ophrys sphegodes are pollinated by pseudocopulating males of the solitary bee Andrena nigroaenea. We investigated the changes in odor emission and reduced attractiveness that occur after pollination in these plants. We analyzed floral odor of unpollinated and pollinated flowers by gas chromatography and compared relative and absolute amounts of electrophysiologically active compounds. Headspace odor samples of O. sphegodes flowers showed a significant increase in absolute and relative amounts of all-trans-farnesyl hexanoate after pollination. Flower extracts also indicated an increase of farnesyl hexanoate after pollination. The total amount of the other physiologically active odor compounds decreased slightly. Farnesyl hexanoate is a major constituent of the Dufour's gland secretion in females of the pollinator bees, A. nigroaenea, where it functions in the lining of the brood cells. Furthermore, this compound lowers the number of copulation attempts in males. In dual-choice tests, we showed that flowers artificially scented with an amount of farnesyl hexanoate equal to the increased amount after pollination were significantly less attractive than flowers treated with solvent only. We propose that the increased production of farnesyl hexanoate in pollinated flowers is a signal to guide pollinators to unpollinated flowers of the inflorescence, which represents a new mechanism in this pollination system"
Keywords:		Andrena nigroaenea Farnesyl hexanoate Ophrys sphegodes Pollinator behavior Post-pollination odor changes;
Notes:		"PubMed-not-MEDLINESchiestl, Florian P Ayasse, Manfred eng Germany 2001/02/01 Oecologia. 2001 Feb; 126(4):531-534. doi: 10.1007/s004420000552. Epub 2001 Feb 1"