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Proc Natl Acad Sci U S A

Title:		Selection for chemical trait remixing in an invasive weed after reassociation with a coevolved specialist
Author(s):		Zangerl AR; Stanley MC; Berenbaum MR;
Address:		"Department of Entomology, 320 Morrill Hall, University of Illinois at Urbana-Champaign, 505 South Goodwin, Urbana, IL 61801-3795, USA"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2008
Volume:		20080131
Issue:		12
Page Number:		4547 - 4552
DOI:		10.1073/pnas.0710280105
ISSN/ISBN:		1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking)
Abstract:		"The interaction between Depressaria pastinacella (parsnip webworm) and wild parsnip (Pastinaca sativa), in its native Europe and in its longstanding nonindigenous range in the midwestern United States, is characterized by chemical phenotype matching, ostensibly mediated by reciprocal selective responses. The first appearance of D. pastinacella on P. sativa in New Zealand in 2004 provided an opportunity to quantify selective impacts of a coevolved herbivore and calibrate rates of phytochemical response in its host plant. Webworms in 2006 reduced seed production up to 75% in New Zealand populations, and in 2007 infestations increased in severity in all populations except one. Most New Zealand populations fall into a furanocoumarin phenotype cluster distinct from European and U.S. phenotypes, although one heavily attacked population clusters with two U.S. populations and one European population long associated with webworms. Multivariate selection analysis substituting realized fitness (with webworms present) for potential fitness (absent webworms) as the dependent variable revealed that reassociation with a coevolved specialist in a nonindigenous area profoundly altered the selection regime, favoring trait remixing and rapid chemical changes in parsnip populations, as predicted by the geographic mosaic theory. That uninfested populations of New Zealand parsnips contain higher amounts of octyl acetate, a floral volatile used by webworms for orientation, suggests that plants that escape from specialized enemies may also experience selection to increase kairomones, as well as to reduce allomones"
Keywords:		"Animals *Biological Evolution Europe Flowers/chemistry/parasitology Furocoumarins/analysis *Host-Parasite Interactions Lepidoptera/growth & development/*physiology New Zealand North America Pastinaca/*parasitology Phylogeny Pupa *Quantitative Trait, Herit;"
Notes:		"MedlineZangerl, A R Stanley, M C Berenbaum, M R eng Research Support, U.S. Gov't, Non-P.H.S. 2008/02/02 Proc Natl Acad Sci U S A. 2008 Mar 25; 105(12):4547-52. doi: 10.1073/pnas.0710280105. Epub 2008 Jan 31"