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- Fogelström, Elsa, et al.
(author)
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Phenotypic but not genotypic selection for earlier flowering in a perennial herb
- 2019
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In: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 107:6, s. 2650-2659
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Journal article (peer-reviewed)abstract
- 1. Timing of reproduction affects the outcome of interactions between plants and their pollinators, grazers and seed predators, as well as with their local abiotic environment. In seasonal environments, phenotypic selection has often been shown to favour early flowering. Yet, we still know little about the agents driving selection in natural populations and whether observed phenotypic selection corresponds to genotypic selection – a prerequisite for evolutionary change.2. In this study, we experimentally assessed phenotypic and genotypic selection for flowering time in a natural population of the perennial herb Lathyrus vernus. We transplanted sibling individuals, obtained through controlled crosses, to their source population and found net phenotypic selection for earlier flowering in the field.3. Despite a higher susceptibility to roe deer grazing, early‐flowering plants had higher fruit set and more seeds per fruit than late‐flowering plants. We found no support for genotypic selection on flowering time, and heritability for first flowering day was very low.4. Synthesis: Our results suggest that commonly observed patterns of higher fitness in early‐flowering plants do not always correspond to selection on genotypic values and are thus not necessarily expected to result in evolutionary change even if the relationship between flowering time and fitness is causal. This finding should be important to understand how species phenology might respond to changing environmental conditions.
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| 2. |
- Fogelström, Elsa, 1986-
(author)
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Plant phenology in seasonal environments
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Phenology, or the seasonal timing life-history events such as emergence, reproduction and senescence will determine the outcome of interactions between plants and both abiotic and biotic aspects of the environment. Such timing is therefore of utmost importance for plants in seasonal environments. In this thesis, I first investigated the factors determining the start, end and length of the growing season for a perennial herb. Secondly, I estimated phenotypic selection on flowering time and investigated to which extent it corresponded to genotypic selection in a natural field setting. Thirdly, I estimated population differentiation in flowering time in a common garden and in the field. Lastly, I experimentally manipulated the synchrony of a perennial herb and its main herbivore to investigate the effects of herbivore phenological preference and plant-herbivore synchrony on the direction of selection on flowering time.I found that flowering individuals emerged earlier in spring than non-flowering individuals and that large individuals senesced later in autumn, suggesting that the length of the growing season is linked to individual condition and resource demands. Phenotypic selection favoured early-flowering individuals, but there was no genotypic selection. I found evidence for genetic population differentiation in flowering time in a common garden but not in the field. This suggests that, although flowering time has a genetic component, the observed variation in flowering time was mainly plastic under natural field conditions. Lastly, I show that constant herbivore preferences of plant phenology, in combination with environmentally driven variation in relative synchrony of the plant and the herbivore, leads to among-year variation in natural selection on flowering time. With this thesis, I contribute to identifying the factors affecting plant phenology as well as of the mechanisms shaping selection on flowering time in perennial plants. Such knowledge is essential for predicting species responses to climate change.
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