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NATURAL SELECTION ON FLORAL TRAITS THROUGH MALE AND FEMALE FUNCTION IN WILD POPULATIONS OF THE HETEROSTYLOUS DAFFODIL NARCISSUS TRIANDRUS
Author(s) -
Hodgins Kathryn A.,
Barrett Spencer C. H.
Publication year - 2008
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/j.1558-5646.2008.00404.x
Subject(s) - biology , hermaphrodite , sexual selection , natural selection , selection (genetic algorithm) , directional selection , disruptive selection , reproductive success , natural population growth , sex allocation , population , mate choice , zoology , narcissus , botany , offspring , genetic variation , demography , genetics , pregnancy , artificial intelligence , sociology , computer science , gene , mating
Measurements of natural selection in hermaphrodite populations require the analysis of performance through both female and male sex functions. Here, we investigate selection on three floral traits: flower number, flower length, and corona width through both sex functions in natural populations of the tristylous daffodil Narcissus triandrus . Selection through female function was examined in six populations, and in two of these we also estimated male selection gradients using multilocus microsatellite genotyping of parents and offspring. We detected significant directional selection for flower number through female function, and significant stabilizing selection for corona width and flower length through male function. Variation in male reproductive success was strongly influenced by the distance between mates and was significantly higher than variation in female reproductive success in one population, a result consistent with Bateman's principle. However, variation through both sex functions was similar in the other population and there was a significant negative correlation between female and male fitness indicating sex‐specific trade‐offs in reproductive success. Selection on floral design in N. triandrus was stronger through male than female function probably because floral morphology plays an important role in promoting effective cross‐pollen transfer in populations of this heterostylous species.