For four years, I quantified the effects of three herbivores--a specialist chrysomelid beetle, Blepharida rhois, a specialist stem borer, Oberea ocellata, and whitetail deer--on the growth, mortality and fruit production of smooth sumac, Rhus glabra. I used selective exclosures to create ramets within a sumac clone that had different herbivore histories. Each year, the past history of a ramet was incorporated into herbivore treatments. I also documented how use of ramets by each herbivore related to previous attack by other herbivores. I found both negative and positive associations between species. Several experiments were designed to determine the underlying mechanisms behind these associations. / I found that chrysomelid herbivory significantly reduced ramet growth, survivorship and fruit production. These negative effects were persistent, lasting for a minimum of two years after attack had ceased. Deer browse was consistently associated with increased vegetative growth and sometimes with increased fruit production. These benefits of browse may be attributable to the selection by deer of larger ramets, rather than to positive effects of browse. There did not seem to be any strong interaction between beetle and deer attack in any year. Over four years, chrysomelid beetles exerted the strongest selective pressure on sumac both as a result of direct and indirect effects. Using common garden experiments, I determined that there were both plant genotypic and environmental factors contributing to sumac resistance to beetle attack. Because of this result, both diversifying and frequency-dependent selection could operate to maintain genetic variability in beetle resistance within the sumac population. / Source: Dissertation Abstracts International, Volume: 49-12, Section: B, page: 5126. / Major Professor: Daniel S. Simberloff. / Thesis (Ph.D.)--The Florida State University, 1988.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77922 |
| Contributors | Strauss, Sharon Yehudit., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 134 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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