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Frank Frey (Assistant Professor)Department of Biology, Colgate University Phone: (315) 228-7871 Fax: (315) 228-7997 E-Mail: ffrey@mail.colgate.edu Research Interests: Evolution and ecology of plant-animal interactions, plant reproductive biology. [Details] Teaching Interests: Evolutionary Ecology and Environmental Studies [Details] |
Frank M. Frey
Research Interests:
As an evolutionary ecologist and plant reproductive biologist, I am interested in using experimental and theoretical techniques to ask questions about factors generating, shaping, and maintaining phenotypic diversity in natural plant populations. Currently, my research is focused on investigating the following questions: (1) What are the underlying ecological mechanisms by which floral trait variation is maintained in natural plant populations; (2) How does community composition affect the magnitude and direction of selection on floral traits; (3) What are the factors underlying the evolution of sexually dimorphic characters in flowering plants; and (4) What is the relationship between symmetry and fitness?
Maintenance of floral-trait variation
As part of my dissertation work, I investigated the maintenance of floral-color variation in a spring ephemeral, Spring Beauty (Claytonia virginica). Using a portable spectrophotometer and a series of field and greenhouse experiments, as well as a multi-year population study, I was able to demonstrate that:
* Although floral-color is a quantitative trait, plants typically fall into one of four main color classes
* Individuals in each of the four color classes are essentially "built" in the same way, and floral color can evolve (mostly) independent of other traits.
* There is little pollinator-mediated selection on floral color in natural populations (pollinators do not preferentially visit the different color morphs)
* There is opposing, directional selection on floral color through natural enemies. "Whiter" flowered individuals receivemore pathogen damage than "redder" flowered individuals, whereas "redder" flowered plants receive substantiallymore herbivore damage than "whiter" flowered plants. Both herbivore and pathogen damage have severe fitness consequences.
Related publications and manuscripts
Frey, F. M. (2003). Floral evolution: how pollinators, herbivores, and pathogens maintain floral-color variation in natural populations of Claytonia virginica. Ph.D. Thesis, Indiana University, Bloomington, IN
Frey, F. M. (2003). Opposing natural selection from herbivores and pathogens may maintain floral-color variation in Claytonia virginica (Portulacaceae). Submitted to Evolution
Frey, F. M. (2003). The form and strength of pollinator-mediated selection in nature. In preparation for Ecology
Frey, F. M. (2003). Phenotypic integration and the potential for independent color evolution in a polymorphic spring ephemeral. In preparation for The American Journal of Botany
What's next with the Claytonia project?
A) Multi-season field experiment to test the hypothesis that pollinator-preferences for particular floral-color morphs will change depending on the composition of the background floral community, and contribute to the maintenance of floral-color variation (interest #2 above).
Spring beauties commonly co-occur with a number of other spring ephemerals:
Preliminary data show that as the relative frequencies of Cut-leaved Toothwort (top-left) and Star Chickweed (top-center) increase in natural communities, so too does the relative frequency of redder floral-color morphs of Spring Beauty.
B) Multi-season field experiment to test the hypothesis that negative frequency-dependent selection generated through pollinator preferences for rare color morphs may contribute to the maintenance of floral-color variation.
C) Greenhouse and lab experiments to test the hypothesis that variation in floral color is associated with variation in pollen performance. (the same pigments responsible for color in Spring Beauty that also influence defense have been shown to affect pollen performance in other systems)
NEW SYSTEMS: Populations of Herb Robert (Geranium robertianium) and Musk Mallow (Malva moschata) exhibit different types of floral-color variation. Individuals of Herb Robert show quantitative floral-color variation with flowers ranging from white to red and all shades in between, whereas individuals of Musk Mallow show discrete floral-color variation with flowers either white, pink or purple. Both flower in the late-summer or early-fall, and I have located several populations within 20 minutes of Colgate's campus. I will be performing several preliminary field experiments with both species this semester and will be investigating the genetics of flower color this coming winter in the greenhouse.
Evolution of sexual dimorphism in flowering plants
In an ongoing collaboration with my Ph.D. advisor (Prof. Lynda Delph, Indiana University), I have been investigating the evolution of flower size dimorphism between males and females of Silene latifolia. In this collaborative effort, I have looked at how the underlying genetic architecture of floral traits between the sexes may facilitate the evolution of flower size dimorphism, and performed field experiments investigating how variation in flower number (which is associated with variation in flower size) among males affects siring success. In addition, we have developed a general, demographic model that identifies crucial trait associations that are necessary for the evolution of sexual dimorphism, and are in the process of expanding this model to its analytical counterpart.
Related publications and manuscripts
Delph, L.F., J.L. Gehring, F.M. Frey, A.M. Arntz, M. Levri. (2003). Genetic constraints on floral evolution in a sexually dimorphic plant revealed by artificial selection. In preparation for Evolution.
Frey, FM and L.F. Delph (2003). A demographic approach to modeling the evolution of sexually dimorphic flower production. In preparation.
The relationship between symmetry and fitness
In collaboration with Lynda Delph and Ryan Davis (undergraduate at IU), I am investigating how variation in floral symmetry affects reproductive success. To test the hypothesis that deviations from perfect floral symmetry result in reduced fitness we have performed a series of artificial flower manipulations in populations of Yellow Jewelweed (Impatiens pallida). Our preliminary data set shows no association between pollinator visitation and symmetry - even severely asymmetrical flowers have the same seed set per fruit as perfectly symmetrical flowers. We are currently building this data set though additional treatments and data collection.
Teaching Interests:
In all my courses, I seek to inspire excitement and wonder about the natural world, and encourage students to use their imagination and creativity to develop testable hypotheses about biological phenomena. Currently, I am involved with our department's introductory Evolution, Ecology, and Diversity course and ENST's Earth and Environmental Processes course. I plan on offering courses in Ethnobotany, Field Biology, and Evolutionary Genetics in the near future.
I am interested in developing innovative ways to effectively teach evolutionary concepts in the classroom. In collaboration with Prof. Curt Lively and Prof. Butch Brodie (Indiana University), I have been developing a series of interactive exercises that teach the following concepts:
1) Evolution by natural selection and basic quantitative genetics
2) Population genetics
3) Negative frequency-dependent selection
4) Game theory (Hawk-Dove and Hawk-Dove-Bourgeois)
5) Sexual selection
We plan on posting these exercises as pdfs on this website soon.
Recent Publications:
Good-Avila S.V., F. Frey, and A.G. Stephenson. 2001. The effect of partial self-incompatibility on the breeding system of Campanula rapunculoides L. (Campanulaceae) under conditions of natural pollination. International Journal of Plant Sciences 162: 1081-1087.
