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Title: Data from: Experimental studies of adaptation in Clarkia xantiana. III. Phenotypic selection across a subspecies border
Sister taxa with distinct phenotypes often occupy contrasting environments in parapatric ranges, yet we generally do not know whether trait divergence reflects spatially-varying selection. We conducted a reciprocal transplant experiment to test whether selection favors “native phenotypes” in two subspecies of Clarkia xantiana (Onagraceae), an annual plant in California. For four quantitative traits that differ between subspecies, we estimated phenotypic selection in subspecies’ exclusive ranges and their contact zone in two consecutive years. We predicted that in the arid, pollinator-scarce eastern region, selection favors phenotypes of the native subspecies parviflora: small leaves, slow leaf growth, early flowering, and diminutive flowers. In the wetter, pollinator-rich, western range of subspecies xantiana, we expected selection for opposite phenotypes. We investigated pollinator contributions to selection by comparing naturally-pollinated and pollen-supplemented individuals. For reproductive traits and for subspecies xantiana, selection generally matched expectations. The contact zone sometimes showed distinctive selection, and in ssp. parviflora selection sometimes favored non-native phenotypes. Pollinators influenced selection on flowering time but not on flower size. Little temporal variation in selection occurred, possibly because of plastic trait responses across years. Though there were exceptions and some causes of selection remain obscure, phenotypic differentiation between subspecies appears to reflect spatially variable selection.  more » « less
Award ID(s):
1754299
PAR ID:
10556062
Author(s) / Creator(s):
; ;
Publisher / Repository:
Dryad
Date Published:
Subject(s) / Keyword(s):
range margins phenotypic selection analysis parapatric geographic distributions
Format(s):
Medium: X Size: 345119 bytes
Size(s):
345119 bytes
Location:
California
Right(s):
Creative Commons Zero v1.0 Universal
Sponsoring Org:
National Science Foundation
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