Evol Ecol Res 7: 161-181 (2005) Full PDF if your library subscribes.
Phenological assortative mating in flowering plants: the nature and consequences of its frequency dependence‡
A.E. Weis,1* J. Winterer,2 C. Vacher,3 T.M. Kossler,1 C.A. Young1 and G.L. LeBuhn4
1Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA, 2Department of Biology, Franklin and Marshall College, Lancaster, PA 17604, USA, 3ISEM – Université Montpellier II, Place Eugène Bataillon, CC 065, 34095 Montpellier Cedex 5, France and 4Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
Author to whom all correspondence should be addressed.
It has long been supposed that variation in mating phenology leads to assortative mating, but its inherent frequency dependence has not been examined. When plants in a population vary in their flowering schedule, the phenotypic (and genetic) composition of the mating pool changes over the season; this causes phenological assortative mating even if pollen is exchanged at random during each interval of the season. Phenotype frequencies govern this temporal shift in the mating pool and this makes phenological assortative mating frequency dependent. We studied phenological assortative mating in four steps. First, we derived a method to estimate the phenotypic correlation between mates from flowering schedules; this correlation, symbolized by ρ, is the standard measure of assortative mating. Next, in a one-locus, two-allele system, we showed that the correlation between mates decreases as one or the other allele approaches fixation, but increases as the population deviates from Hardy-Weinberg proportions. Third, we showed that unlike assortative mating based on fixed preferences, the level of phenological assortment in one generation influences the level of assortment in the next, such that ρ reaches an equilibrium value that depends on allele frequencies. Finally, we contrasted the effects of frequency-dependent, phenological assortative mating on directional selection to the effects of fixed levels of assortative mating. When allelic effects were additive, frequency dependence slightly accelerated the selection response, compared with a fixed ρ. When one allele was dominant, phenological assortment slightly decelerated the selection response. Similarities between assortative mating through phenology and through habitat preference can cause the latter also to be frequency dependent.
Keywords: flowering phenology, genetic variance, natural selection.
DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.
© 2005 A.E. Weis. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.
Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.
All copies of abstracts and articles must preserve their copyright notice without modification.