Date of Award

1-30-2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

First Advisor

Colin Hughes

Abstract

The population genetic structure and extra-pair paternity were investigated using microsatellite markers in a Neotropical parrot, the Green-rumped Parrotlet (Forpus pesserinus). Blood samples were taken from adults at 6 natural populations from the Llanos of Venezuela and 160 families from the Hato Masaguaral population. Adult samples were screened at 10 microsatellite loci. Offspring were screened at 3 loci. Parentage analysis of 827 offspring revealed an extra-pair fertilization (EPF) rate of 7.7% young (n = 64) in 14.4% of nests (n = 23). No offspring resulted from intra-specific parasitism. Identification of genetic paternity was attempted for all extra-pair young. Comparisons of physical and life history characteristics of cuckolded and extra-pair males revealed that only survival after the EPF was significantly different. Comparisons of cuckolded and non-cuckolded pairs revealed a significant difference in age between the females and their mates. Genotypic proportions within populations revealed 3 loci that differed from expected Hardy-Weinberg equilibrium. Mean observed heterozygosity was 0.60. Mantel's test of the relationship between population pair-wise calculations of RST and geographic distance was significant, suggesting restricted geneflow among distant populations. Mantel's test comparing RST values among subdivisions of the Hato Masaguaral population and geographic distance were not significant, suggesting sufficient geneflow to restrict population differentiation on small scales (less than 2 kilometers).

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