On the evolution of floral traits : Variation in complex floral phenotypes across pollination environments
Hildesheim, Laura Sophie LU
(2025)
- Abstract
- Pollinators play a central role in shaping the astounding diversity of angiosperm flowers. Flowers are complex, multidimensional, genetically and functionally integrated phenotypes, rendering it a challenge to quantify and interpret observed trait variation. Even variation in simpler trait measurements is a challenge to interpret, because of the multitude of selective agents and evolutionary processes shaping floral form. The long-term pollination environment of a plant population is reflected in its pollination- and mating system. Here, I employed a geographic comparative approach, using natural variation in floral traits across pollination environments to understand the evolution of complex floral traits along the pathway to pollination.... (More)
- Pollinators play a central role in shaping the astounding diversity of angiosperm flowers. Flowers are complex, multidimensional, genetically and functionally integrated phenotypes, rendering it a challenge to quantify and interpret observed trait variation. Even variation in simpler trait measurements is a challenge to interpret, because of the multitude of selective agents and evolutionary processes shaping floral form. The long-term pollination environment of a plant population is reflected in its pollination- and mating system. Here, I employed a geographic comparative approach, using natural variation in floral traits across pollination environments to understand the evolution of complex floral traits along the pathway to pollination. Specifically, I studied the evolution of floral scent as a pollinator advertisement and reward trait, flower-pollinator fit traits that mediate successful pollen transfer, and pollen performance traits involved in the fertilization process. First, I associated scent evolution with pollinator shifts in a specialized pollination system. Biosynthetically novel scent compounds mediated a shift from floral scent as a pollinator advertisement to a pollinator reward and precipitated a qualitative pollinator shift. Second, I quantified genetic and functional constraints in the evolution of pollinator fit traits as part of three-dimensional flower morphology. The evolutionary potential of each trait was tightly linked to its realized evolution. Third, I quantified components of variance in pollen performance across mating systems. Patterns of pollen performance varied idiosyncratically across pollination environments due to other sources of variation. Lastly, I studied the joint evolution of pollen longevity and mating system. Pollen longevity was longest in the most unreliable pollination environment allowing for delayed pollination. This thesis contributes to a better understanding of the role of pollinators in the diversification of complex floral phenotypes. I combined an understanding of the complexity of the traits under study, profound knowledge of the ecology and natural history of the study systems, and insight into the evolutionary processes shaping trait variation, to understand the evolution of complex floral phenotypes. This work is crucial for understanding the evolution of floral diversity, as well as predicting the consequences of changing pollinator communities for plant fitness. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/66396d3c-9b7d-4668-867c-0ccceaaa3b48
- author
- Hildesheim, Laura Sophie
LU
- supervisor
-
- Øystein Opedal LU
- Magne Friberg LU
- opponent
-
- Professor Ashman, Tia-Lynn, University of Pittsburgh.
- organization
- publishing date
- 2025
- type
- Thesis
- publication status
- published
- subject
- keywords
- Arabis alpina, biosynthetic novelty, complex phenotypes, Dalechampia, delayed pollination, evolvability, floral scent, flower evolution, genetic constraints, mating system, plasticity, pollen longevity, pollen performance, pollination environment, pollinator fit, pollinator reward, trait variation, specialized pollination system
- pages
- 67 pages
- publisher
- Lund University
- defense location
- Blå Hallen, Ekologihuset. Join via zoom: https://lu-se.zoom.us/j/65518649814?pwd=A6St3QXZ9UrvLxFMrVajqfnvX0kM3U.1
- defense date
- 2025-03-28 09:00:00
- ISBN
- 978-91-8104-185-9
- 978-91-8104-186-6
- language
- English
- LU publication?
- yes
- id
- 66396d3c-9b7d-4668-867c-0ccceaaa3b48
- date added to LUP
- 2025-02-18 19:41:55
- date last changed
- 2025-04-04 14:08:18
@phdthesis{66396d3c-9b7d-4668-867c-0ccceaaa3b48,
abstract = {{Pollinators play a central role in shaping the astounding diversity of angiosperm flowers. Flowers are complex, multidimensional, genetically and functionally integrated phenotypes, rendering it a challenge to quantify and interpret observed trait variation. Even variation in simpler trait measurements is a challenge to interpret, because of the multitude of selective agents and evolutionary processes shaping floral form. The long-term pollination environment of a plant population is reflected in its pollination- and mating system. Here, I employed a geographic comparative approach, using natural variation in floral traits across pollination environments to understand the evolution of complex floral traits along the pathway to pollination. Specifically, I studied the evolution of floral scent as a pollinator advertisement and reward trait, flower-pollinator fit traits that mediate successful pollen transfer, and pollen performance traits involved in the fertilization process. First, I associated scent evolution with pollinator shifts in a specialized pollination system. Biosynthetically novel scent compounds mediated a shift from floral scent as a pollinator advertisement to a pollinator reward and precipitated a qualitative pollinator shift. Second, I quantified genetic and functional constraints in the evolution of pollinator fit traits as part of three-dimensional flower morphology. The evolutionary potential of each trait was tightly linked to its realized evolution. Third, I quantified components of variance in pollen performance across mating systems. Patterns of pollen performance varied idiosyncratically across pollination environments due to other sources of variation. Lastly, I studied the joint evolution of pollen longevity and mating system. Pollen longevity was longest in the most unreliable pollination environment allowing for delayed pollination. This thesis contributes to a better understanding of the role of pollinators in the diversification of complex floral phenotypes. I combined an understanding of the complexity of the traits under study, profound knowledge of the ecology and natural history of the study systems, and insight into the evolutionary processes shaping trait variation, to understand the evolution of complex floral phenotypes. This work is crucial for understanding the evolution of floral diversity, as well as predicting the consequences of changing pollinator communities for plant fitness.}},
author = {{Hildesheim, Laura Sophie}},
isbn = {{978-91-8104-185-9}},
keywords = {{Arabis alpina; biosynthetic novelty; complex phenotypes; Dalechampia; delayed pollination; evolvability; floral scent; flower evolution; genetic constraints; mating system; plasticity; pollen longevity; pollen performance; pollination environment; pollinator fit; pollinator reward; trait variation; specialized pollination system}},
language = {{eng}},
publisher = {{Lund University}},
school = {{Lund University}},
title = {{On the evolution of floral traits : Variation in complex floral phenotypes across pollination environments}},
url = {{https://lup.lub.lu.se/search/files/208659470/Laura_Hildesheim_-_WEBB.pdf}},
year = {{2025}},
}