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Chronic selection for early reproductive phenology in an annual plant across a steep, elevational gradient of growing season length
Author(s) -
Ensing David J.,
Sora Dylan M. D. H.,
Eckert Christopher G.
Publication year - 2021
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.14274
Subject(s) - phenology , biology , natural selection , selection (genetic algorithm) , growing season , adaptation (eye) , phenotypic plasticity , local adaptation , ecology , directional selection , genetic variation , population , demography , genetics , gene , artificial intelligence , neuroscience , sociology , computer science
Colonization along ubiquitous gradients of growing season length should require adaptation of phenological traits, driven by natural selection. Although phenology often varies with season length and genetic differentiation in phenological traits sometimes seems adaptive, few studies test whether natural selection is responsible for these patterns. The annual plant Rhinanthus minor is genetically differentiated for phenology across a 1000‐m elevational gradient of growing season length in the Canadian Rocky Mountains. We estimated phenotypic selection on five phenological traits for three generations of naturally occurring individuals at 12 sites ( n = 10,112), and two generations of genetically and phenotypically more variable transplanted populations at nine of these sites ( n = 24,611). Selection was weak for most traits, but consistently favored early flowering across the gradient rather than only under short seasons. There was no evidence that apparent selection favoring early reproduction arose from failure to consider all components of fitness, or variation in other correlated phenological traits. Instead, selection for earlier flowering may be balanced by selection for strong cogradient phenological plasticity that indirectly favors later flowering. However, this probably does not explain the consistency of selection on flowering time across this steep, elevational gradient of growing season length.