Source: Dissertation Abstracts International, Volume: 40-02, Section: B, page: 0577. / Thesis (Ph.D.)--The Florida State University, 1978.

Source: Dissertation Abstracts International, Volume: 40-06, Section: B, page: 2508. / Thesis (Ph.D.)--The Florida State University, 1978.

Sailfin mollies, Poecilia latipinna, display dramatic interdemic variation in average male body size. Size at maturity in sailfin mollies is a one locus Y-linked trait with a minimum of four alleles; males are the heterogametic sex and grow little after maturing. / Most of the variation in male size is expressed among local demes. I sampled from sixty molly populations from the eastern third of their range and found regional differences explain 6% of the total variation in male size, local differences 20%, and seasonal differences 5%. Furthermore, there is no correlation of habitat type to average male size or spread of male sizes. I constructed an index of the habitat experienced by each population through principal components analysis. The index proved to be uncorrelated with male size variation using Mantel's method. / I found sailfin mollies to have a high migration rate among demes such that stochastic population genetic processes are an unlikely explanation of their extensive local size variation. I determined this though a survey of allozyme variation at thirty presumptive loci. Approximately 20% of allozyme variation is among geographic regions, while only 3% of allozyme variation occurs within regions. / I have found both environmental and genetic bases for size variation through reciprocal transplant experiments conducted in field cages. Most of the genetic variation in size at maturity is present among family groups within demes. A laboratory factorial experiment allowed me to determine that male size at maturity is conserved across a range of temperatures, salinities, and food levels. Males matured later, but at the same size under relatively cool conditions. / The discrepancy in geographic variation of allozymes and size indicates selective intensities differ for these traits. I argue that this suggests selection shapes size variation. I found independent evidence for the operation of selection on size in my field experiment; relatively large fish at three weeks of age were more likely to survive to maturity under some conditions. Also, I reared large males in the lab from one population where large mollies have never been collected. The laboratory results exclude environmental influence as an explanation for this discrepancy. / Source: Dissertation Abstracts International, Volume: 47-12, Section: B, page: 4755. / Thesis (Ph.D.)--The Florida State University, 1986.

Adults and nymphs of three species of mites (Unionicola abnormipes, U. fossulata, and U. serrata) co-occur in the bivalve hosts, Villosa villosa, V. vibex, and Uniomerus declivis, in St. Mark's River, north Florida. Monthly samples of mussels at three sites over three years established that mean infrapopulation sizes, prevalences, and frequency distributions of mites among hosts varied greatly between mite species. Adults of only one mite species fitted predictions derived from one published model of population regulation. All other mites exhibited characteristics of two different models because of variation between sites, years, and host species, indicating that current models of regulation of parasite populations are inappropriate for these mites. / Mite species had frequently higher abundances in one host species. De-mited mussels placed out monthly at each site showed that these higher abundances are achieved within a month. Recruitment varied greatly between sites, years, and months but, because it was consistently high, did not have a significant, final effect on mite abundances with two exceptions: no recruitment by U. abnormipes at one site and no recruitment by adult U. fossulata, which enter mussels as nymphs and remain in the same mussels after metamorphosis. Consequently, the significance of any interactions between mites depends on locality and time of year, but models often assume that recruitment rates do not vary significantly. / Two field experiments indicated that the low abundance of U. abnormipes in the larger host species, Uniomerus declivis, was caused by competitive, and possibly predatory, interactions with U. serrata. However, U. serrata did not occur in Villosa villosa, in which U. abnormipes reaches its highest abundance, because most of these mussels are too small. Numbers of U. abnormipes are reduced also by adult U. fossulata but there is no evidence that U. fossulata prey upon U. abnormipes or exclude them from hosts. / Interactions between mites did not occur as predicted by either simple, theoretical models or more biologically-realistic ones developed for other systems but did demonstrate that experimental tests of models are essential. / Source: Dissertation Abstracts International, Volume: 49-06, Section: B, page: 2039. / Co-Major Professors: Daniel S. Simberloff; William H. Heard. / Thesis (Ph.D.)--The Florida State University, 1988.

Morphological convergence is defined here as evolution toward similar dimensions of traits in unrelated animals that live in the same or similar environments. Because a genus is a taxonomic unit in which differences among congeners represent directional changes in morphology from a common ancestor, I look for evidence of morphological convergence by comparing sets of congeneric species of birds that breed in peatland habitats of northern Minnesota and eastern Finland. / I identified similar peatland habitats in Finland and in Minnesota in a space determined by discriminant function analysis. Shrub areas and coniferous forest areas were similar to shrub areas and coniferous forest areas, respectively, regardless of continent. Therefore, I identified four genera in Minnesota, Zonotrichia, Spizella, Geothlypis, and Dendroica, and one in Finland, Emberiza, with species in shrub and in coniferous forest peatlands and compared their morphology. / The species in shrub vegetation were smaller, had relatively longer pelves and legs, and had wider and shallower sterna compared with their congeners in coniferous forest. With the exception of Emberiza, the length of the bill and the length of the wings were also relatively longer for the shrub-dwelling peatland species. Warblers breeding in shrub peatlands had relatively deeper and wider bills, but sparrows had relatively shallower and narrower bills compared with their congeners in coniferous forests. / These results indicate significant (p = .03) directional patterns among taxonomically distantly-related genera for morphology associated with movement through the vegetation. Morphology associated with feeding, however, shows trends at a familial level that probably reflect differences in diet and behavior between sparrows and warblers. The consistency of the patterns emphasizes (1) the relationship between morphology and habitat structure or behavior, and (2) the likelihood of a common underlying mechanism for these patterns. / Source: Dissertation Abstracts International, Volume: 44-02, Section: B, page: 0401. / Thesis (Ph.D.)--The Florida State University, 1983.

No description available.

No description available.

No description available.

No description available.

No description available.