In Chapter I, I tested Opler's (1978) hypothesis regarding leaf miners that feed on oaks with different leaf persistence times by monitoring abundances and species richness of leaf miners on three species of oaks, Quercus falcata, Q. nigra, and Q. hemisphaerica (Fagaceae). No significant differences among oak species was found for either densities or species richness of leaf miners. Moreover, my results show that leaf-mining densities are negatively and significantly correlated with nitrogen content, suggesting the leaf miners may not be sensitive (in terms of population sizes) to seasonal decreases in nitrogen content of oak leaves. / In Chapter II, to test for spatial and temporal differences in mortality factors and survivorship, I experimentally isolated oak trees by transplanting them into agricultural fields. Parasitism by hymenopterans significantly decreases for leaf miners on isolated trees, thus increasing larval survivorship. However, increased survivorship does not result in higher abundances in subsequent generations because on at least small trees, leaf-mining populations are maintained by continual re-immigration with little or no in situ reproduction and colonization. / In Chapter III, five species of oaks were fully enclosed with fine mesh screening or the leaf litter beneath the tree was covered with a plastic cage to test for the contribution of in situ and long range colonization respectively by leaf miners to small trees. My results indicate that both population sizes and species richness of leaf miners are maintained on small trees primarily by long range colonization and little or no in situ colonization and reproduction occurs. This suggests that it may be incorrect to consider leaf-mining populations on small trees as in dynamic equilibrium because they represent mostly transient individuals and do not sustain breeding populations. / In Chapter IV, densities of a leaf miner, Cameraria sp. nov., are experimentally increased on an enclosed oak tree. Even though densities are significantly higher on the caged tree as compared to a control, I find no evidence for intraspecific competition. Instead, survivorship of larval leaf miners increased on the caged tree. These results suggest that parasitism, and possibly predation, regulate population densities of this leaf miner below which competition would usually occur. / In Chapter V, terrestrial invertebrate predators were excluded from oak trees to determine if they are a significant mortality factor for a species of leaf-mining insect, Eriocraniella sp. nov. Larval survivorship was significantly higher and predation lower on trees that had gound-dwelling invertebrate predators excluded. / In Chapter VI, I ascertained whether oak leaves that were mined abscised earlier than undamaged leaves by collecting and examining leaves in leaf baskets placed beneath oak trees. My results indicate that significantly more mined leaves abscise earlier than unmined ones and that propensity of mined leaves to fall depends on size of the oak leaf and phenology of the particular oak species. Life table analysis of two leaf miners, Tischeria purinosella and Brachys ovatus, show that early leaf abscission is an important mortality factor for larval leaf miners. / Source: Dissertation Abstracts International, Volume: 41-05, Section: B, page: 1631. / Thesis (Ph.D.)--The Florida State University, 1980.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74195 |
| Contributors | FAETH, STANLEY HERMAN., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 232 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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