Floral Evolution In Milkweeds
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Floral Evolution In Milkweeds
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Author : Raffica Jeanne La Rosa
language : en
Publisher:
Release Date : 2015
Floral Evolution In Milkweeds written by Raffica Jeanne La Rosa and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Asclepiadaceae categories.
Adaptation is an important process that allows species to utilize new habitats and to avoid extinction, contributing to the biodiversity we find on the planet. Many flowering plants rely on animals for pollination; the floral traits that are adaptive for pollination are those that influence attraction, rewards, or efficiency. Milkweeds (Asclepias) have unusual floral structures that consist of a gynostegium surrounded by five nectar-filled hoods. In many species, a horn develops from the inside base of each hood. Pollen grains are packaged into waxy packets (pollinia) and are positioned in the wall of the gynostegium. For fertilization, pollinia must be removed by pollinators and inserted into stigmatic openings in the wall of the gynostegium between adjacent hoods; pollination is carried out passively by a wide variety of pollinators that are almost entirely all insects. Milkweeds are hermaphroditic, so it is possible for the floral traits to be adaptive for male fitness, female fitness, or both. The floral diversity across Asclepias is astounding. My dissertation investigates if and how the floral structures are adaptive, and if the variation among species is the result of natural selection. I used two complementary approaches. For the first approach, I used contemporary measures of selection and functional studies to focus on the process of adaptation in five species of North American Asclepias. Selection works on intraspecific variation within traits and the effect of that variation on fitness. I also utilized paternity analyses in two species to measure selection through male fitness. For the second approach, I used phylogenetic methods to find signatures of past selection on traits across more than one hundred North American Asclepias species. Phylogenetic comparative methods focus on patterns of interspecific variation. I used tests of correlated evolution between pairs of traits, or traits and pollinators, to investigate functional relationships and possible selective agents. I also tested for convergent evolution, which can demonstrate adaptive evolution in response to a similar selective regime. The six floral traits I studied had an effect on fitness, suggesting they are adaptive. I found that many of the floral traits were under significant selection through only one gender, but that the direction of selection was similar across genders, showing little conflict between male and female function or between male and female fitness. I predicted that the size of the hood and gynostegium would influence pollinator attraction, but they were instead more likely to influence the efficiency of pollination. I also found no significant link between female pollination success and female reproductive success in four of the five species, so traits that increased pollen receipt did not in turn affect female fitness, which is consistent with fruit production not being limited by pollen receipt. Using measures of viable seeds produced (annual female fitness) and viable seeds sired (annual male fitness), I determined that selection estimated using total fruit number is a good estimate of selection through viable seeds produced; however, total pollinia removed per plant, a common estimate of male function and fitness in milkweeds is not a good predictor of viable seeds sired. My studies of the gynostegia, hoods, and horns across the phylogeny showed that horn loss likely followed the closure of hoods, suggesting a possible loss of horn function. There were also three convergent floral phenotypes; each may have evolved in response to similar selective regimes. The convergent species provide an excellent starting point for future investigations of possible selective agents.
Floral Evolution
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Author : Frank M. Frey
language : en
Publisher:
Release Date : 2003
Floral Evolution written by Frank M. Frey and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
Selected Papers On Floral Evolution
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Author : Elmar E. Leppik
language : en
Publisher:
Release Date : 1974
Selected Papers On Floral Evolution written by Elmar E. Leppik and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1974 with Flowers categories.
The Milkweed Lands
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Author : Eric Lee-Mäder
language : en
Publisher: Hachette UK
Release Date : 2023-09-26
The Milkweed Lands written by Eric Lee-Mäder and has been published by Hachette UK this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-09-26 with Science categories.
Delve into this fascinating appreciation of milkweed, an often-overlooked plant, and discover an amazing range of insects and organisms that depend on it as the seasons unfold, with this collaboration between a noted ecologist and an award-winning botanical illustrator. Ecologist Eric Lee-Mäder and noted botanical artist Beverly Duncan have teamed up to create this unique exploration of the complex ecosystem that is supported by the remarkable milkweed plant, often over-looked or dismissed as a roadside weed. With stunning, up-close illustrations and engaging text, they trace every stage of the plant's changes and evolutions throughout the seasons, including germination, growth, flowering, and seed development. Simultaneously, they chronicle the lives of the many creatures whose lives are intertwined with the milkweed: monarch butterflies; soldier and queen butterflies; milkweed tussock moths; large and small milkweed bugs; milkweed weevils; bumble bees; goldfinches; and more. The delightful illustrations and illuminating text give the reader the feeling of browsing an avid naturalist's sketchbook, while also learning about different milkweed species, how to propagate milkweed in the garden, the industrial uses of milkweed, interesting milkweed relatives, and more. This publication conforms to the EPUB Accessibility specification at WCAG 2.0 Level AA.
Selected Papers On Floral Evolution I
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Author : Elmar E. Leppik
language : de
Publisher:
Release Date : 1969
Selected Papers On Floral Evolution I written by Elmar E. Leppik and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1969 with Flowers categories.
Generalization In Plant Pollination Systems And Its Effect On Floral Evolution Within And Among Populations Of Wild Radish Raphanus Raphanistrum
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Author : Heather Farrah Sahli
language : en
Publisher:
Release Date : 2006
Generalization In Plant Pollination Systems And Its Effect On Floral Evolution Within And Among Populations Of Wild Radish Raphanus Raphanistrum written by Heather Farrah Sahli and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Fertilization of plants categories.
Ecology And Evolution Of Common Milkweed
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Author : Angela Ricono
language : en
Publisher:
Release Date : 2018
Ecology And Evolution Of Common Milkweed written by Angela Ricono and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Milkweeds categories.
All organisms must interact with and adapt to their surrounding environment. There are myriad ways in which species accomplish this; ultimately resulting in the vast diversity of life on earth today. Changes in the environment can have profound impacts on an organisms' ability to compete and utilize their surroundings. Plants are particularly impacted by local environmental differences because of the fact that they are immobile. This environmental variation exists at both large and small spatial scales. For example, on larger scales, forces such as fire and grazers can remove dominant plant competitors. on smaller scales, variation in resource availability (e.g. light, nutrients, water) may benefit more phenotypically plastic species. to better understand how changes in the environment, on both large and small spatial scales, I established a two part study using milkweed (Asclepias spp.) as a model system. in the first chapter, I ask how fire, large grazers, and nutrients have affected milkweed abundance over relatively long time and large spatial scales. Here I found that most milkweed species increase in abundance with burning alone but expressed species-specific responses to other treatment combinations. This indicates that milkweed species have likely experienced unique fluctuations in abundance as fire and large herbivores moved across the landscape. The second aspect of this research focuses in on a single year and relatively small spatial scales. Here, using common milkweed (A. syriaca), I ask how environmental variation shapes spatial structuring of phenotypes within fine-scale physical distance and how genotypes impact phenotypes. I found that environment, not genotype, had a relatively larger role on fine-scale phenotypic variation. Combined, these results have implications for understanding the role of large and small scale environmental variations in plant phenotypes and plant abundance.
Floral Biology
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Author : David G. Lloyd
language : en
Publisher: Springer
Release Date : 2011-09-15
Floral Biology written by David G. Lloyd and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-09-15 with Science categories.
Studies in floral biology are largely concerned with how flowers function to promote pollination and mating. The role of pollination in governing mating patterns in plant populations inextricably links the evolution of pollination and mating systems. Despite the close functional link between pollination and mating, research conducted for most of this century on these two fundamental aspects of plant reproduction has taken quite separate courses. This has resulted in suprisingly little cross-fertilization between the fields of pollination biology on the one hand and plant mating-system studies on the other. The separation of the two areas has largely resulted from the different backgrounds and approaches adopted by workers in these fields. Most pollination studies have been ecological in nature with a strong emphasis on field research and until recently few workers considered how the mechanics of pollen dispersal might influence mating patterns and individual plant fitness. In contrast, work on plant mating patterns has often been conducted in an ecological vacuum largely devoid of information on the environmental and demographic context in which mating occurs. Mating-system research has been dominated by population genetic and theoretical perspectives with surprisingly little consideration given to the proximate ecological factors responsible for causing a particular pattern of mating to occur.
Directional Trend Of Floral Evolution
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Author : E. E. Leppik
language : en
Publisher:
Release Date : 1968
Directional Trend Of Floral Evolution written by E. E. Leppik and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1968 with Flowers categories.
Monarchs And Milkweed
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Author : Anurag Agrawal
language : en
Publisher: Princeton University Press
Release Date : 2017-03-28
Monarchs And Milkweed written by Anurag Agrawal and has been published by Princeton University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-03-28 with Science categories.
The fascinating and complex evolutionary relationship of the monarch butterfly and the milkweed plant Monarch butterflies are one of nature's most recognizable creatures, known for their bright colors and epic annual migration from the United States and Canada to Mexico. Yet there is much more to the monarch than its distinctive presence and mythic journeying. In Monarchs and Milkweed, Anurag Agrawal presents a vivid investigation into how the monarch butterfly has evolved closely alongside the milkweed—a toxic plant named for the sticky white substance emitted when its leaves are damaged—and how this inextricable and intimate relationship has been like an arms race over the millennia, a battle of exploitation and defense between two fascinating species. The monarch life cycle begins each spring when it deposits eggs on milkweed leaves. But this dependency of monarchs on milkweeds as food is not reciprocated, and milkweeds do all they can to poison or thwart the young monarchs. Agrawal delves into major scientific discoveries, including his own pioneering research, and traces how plant poisons have not only shaped monarch-milkweed interactions but have also been culturally important for centuries. Agrawal presents current ideas regarding the recent decline in monarch populations, including habitat destruction, increased winter storms, and lack of milkweed—the last one a theory that the author rejects. He evaluates the current sustainability of monarchs and reveals a novel explanation for their plummeting numbers. Lavishly illustrated with more than eighty color photos and images, Monarchs and Milkweed takes readers on an unforgettable exploration of one of nature's most important and sophisticated evolutionary relationships.