| curriculum vitae
Department of Ecology and Evolutionary Biology
University of California, Los Angeles
618 Charles E. Young Drive South
P.O. Box 951786
Los Angeles, CA 90095-1786
shannonolsson [at] ucla [dot] edu
Chemical communication between gametes is an essential factor mediating sexual reproduction in organisms as diverse as sea urchins and humans. Chemical signals released by the egg and dissolved into the surrounding medium are detected by chemoreceptors on sperm cells and used by the
sperm to navigate towards the egg. In broadcast spawning organisms such as abalone (Haliotis spp.), this chemically mediated behavior is a key factor ensuring reproductive success. My postdoctoral research examines chemically mediated gamete interactions in five species of broadcast spawning abalone (Haliotis spp.), all living in southern California. In recent years, commercial populations of Haliotis spp. have become seriously threatened or officially endangered due to overfishing, habitat deterioration, and disease. Many abalone populations remain in very low densities and patchy distributions which can severely limit fertilization success and population recovery.
There are seven co-occurring species of abalone with overlapping breeding seasons along the pacific coast of the United States. Species integrity and reproductive isolation has been attributed to species-specific, gamete-recognition proteins on the surface of the egg. However, with additional species-specific long-distance cues, the sperm need not exhaust precious energy resources by swimming to the wrong egg. These sperm attractants may therefore constitute important pre-zygotic agents restricting gene flow and preserving species integrity. They may also serve as a means of increasing genetic divergence among sympatric populations. An understanding of gamete chemocommunication will identify a new mechanism driving the evolution of new species in aquatic habitats.
My research seeks to identify the structures of the sperm chemoattractants, determine rates of chemoattractant production and release, establish chemical structure/function relationships governing species specific sperm attraction, compare the effects of various hydrodynamic environments on abalone chemocommunication and fertilization, and identify the sperm receptors for chemoattractants for all five species. Comparison of the reproductive strategies employed by closely related species will provide important insights into the mechanisms of reproductive isolation and speciation, and improve understanding of basic processes in sensory systems and fertilization biology. The study of these threatened commercial populations will also contribute in the area of marine conservation.
A. ARTICLES IN PEER-REVIEWED JOURNALS:
- Stensmyr, M.C., Larsson, M.C., Bice, S. (MAIDEN NAME), Hansson, B.S. Detection of fruit- and flower-emitted volatiles by olfactory receptor neurons in the polyphagous fruit chafer Pachnoda marginata (Coleoptera: Cetoniinae). Journal of Comparative Physiology A, 187(7): 509-519, 2001.
- Larsson, M.C., Stensmyr, M.C., Bice, S.B. (MAIDEN NAME); Hansson, B.S. Attractiveness of fruit and flower odorants detected by olfactory receptor neurons in the fruit chafer Pachnoda marginata. Journal of Chemical Ecology, 29(5): 1253-1268, 2003.
- Olsson, S.B., Linn, Jr. C.E., Roelofs, W.L. The chemosensory basis for behavioral divergence involved in sympatric host shifts: I. Characterizing olfactory receptor neuron classes responding to key host volatiles. Journal of Comparative Physiology A. DOI 10.1007/s00359-005-0069-2, 2005.
- Olsson, S.B., Linn, Jr. C.E., Roelofs, W.L. The chemosensory basis for behavioral divergence involved in sympatric host shifts: II. Olfactory receptor neuron sensitivity and temporal firing pattern to individual key host volatiles. Journal of Comparative Physiology A. DOI 10.1007/s00359-005-0066-5, 2005.
- Olsson, S.B., Barnard, J., and Turri, L. Olfaction and identification of unrelated individuals: Examination of the mysteries of human odor recognition. Journal of Chemical Ecology, In Press.
- Olsson, S.B., Linn, Jr. C.E., and Roelofs, W.L. Correlating peripheral chemoreception and behavior among hybrid crosses of the Rhagoletis species complex. In Preparation.
- Olsson, S.B., Linn, Jr. C.E., Roelofs, W.L. Abnormal olfactory receptor neuron responses to host volatiles in F1 hybrid Rhagoletis populations. In Preparation.
Zimmer Lab - main
email: shannonolsson [at] ucla [dot] edu