GRADUATE STUDIES BULLETIN

ANNOUNCEMENT

Florida International University

Division of Graduate Studies

Master’s Thesis Defense

Abstract

The Reproductive Biology of Ruellia succulenta (Acanthaceae) and the Effects

of Habitat Fragmentation

by

John H. Geiger

The purpose of this study was to determine the reproductive biology of Ruellia succulenta, the pineland petunia, and to relate this to the effects of habitat fragmentation. The project was composed of the following components: 1) breeding system experiment, 2) inbreeding depression experiment, 3) pollination ecology study, and 4) a study considering the effects of habitat fragmentation on reproduction.

The results of the breeding system experiment, using plants derived from cuttings of Everglades National Park plants, show the pineland petunia to be fully self-compatible and capable of autofertility. The mechanism of autogamy is delayed self-pollination via abscission of the corolla. In addition, no evidence was found of apomictic reproduction.

Utilizing the same maternal plants and their progeny from the breeding system experiment, a separate inbreeding depression study was conducted. Measures of inbreeding depression for several life-history stages were estimated. The only stage that showed significant inbreeding depression was seed weight. Results supported theoretical expectations of reduced inbreeding depression in selfing species and expression of inbreeding depression late in the life cycle for selfing species due to weakly deleterious alleles not easily purged by inbreeding.

The most significant effect of habitat fragmentation, in terms of pollination ecology, was a highly significant difference in the proportion of Hymenopteran and Lepidopteran floral visitors by the size class of habitat. This represented significant changes in the pollinator guild from small to intact habitat.

The most important factor positively affecting reproduction in the different size classes of fragments appears to be time since last fire. Plants that occurred in the most recently burned pine rockland habitat showed the highest measures of reproduction for the components analyzed.

Date: November 14, 2001 Department: Biological Sciences

Time: 1:00 p.m. Major Professor: Dr. Suzanne Koptur

Place: University Park, WC 130