May 4 2010

12:00 BSRB 154

EcoLunch Series

Graduate Student Presentations by Claire Narraway, Greer Dolby and Marisa Tellez


Claire Narraway,

"Group benefit, nepotism and intragenomic conflict: multiple levels of selection on reproductive behaviour in honey bees"
Kin selection is the dominant paradigm to explain the evolution of cooperation. Here, behaviours that negatively affect the actor may be selected for, providing that the behaviour benefits genetic relatives. Control over worker reproduction in eusocial insect colonies is one of kin selections most convincing examples. Yet, kin selection may act at many levels, with differing results. Firstly, the individual level where individuals bias their behaviour to aid those who are most genetically related. Secondly, the group level where efficiently functioning groups are more successful than anarchistic ones. And, finally, at the intragenomic level where maternally and paternally derived genomes may favour very different phenotypes. Here, I will describe the rational behind and the methodology that I will use to elucidate the relative importance of each level of selection in the prima facie example of kin selection, worker policing.

Greer Dolby,

"Phylogeographic patterns and processes in estuarine fishes of southern and Baja California"

Reconstructing the geologic history and mapping modern patterns of genetic diversity in a region reveals the processes generating and maintaining that biodiversity. The Baja California Peninsula provides an ideal setting to fulfill both of these aspects. My dissertation research focuses on testing whether the suggested Pleistocene aged (ca. 1 Ma) Viscaíno Seaway produced the phylogeographic patterns of marine species presently observed along the Pacific and Gulf of California coasts. Evaluating this hypothesis relies on data gathered from detailed study and dating of rock sections in the proposed seaway region along with comprehensive genetic studies across the region mapping population structures of three estuarine fish species. High throughput sequencing (Roche 454) is being used following genome reduction for development of both microsatellite and SNP loci in these three non-model organisms. These data are being analyzed within a recently developed framework of statistical phylogeography that employs a process of general diffusion to describe molecular data. Preliminary work shows support for both the seaway and subsequent patterns of genetic diversity expected. Until now our knowledge has been hampered by a lack of appropriate geologic settings to test diversification processes of marine species. My research employs a cross-disciplinary approach to examine a specific case where such reconstruction and evaluation appear possible.

Marisa Tellez,
"Assessing patterns of host-parasite distribution of Alligator mississippiensis in Louisiana by investigating annual environmental and anthropogenic impacts"


With emerging diseases such as Lyme Disease, SARS, and malaria, understanding the complex linkage between environmental and anthropogenic disturbances and infectious disease is becoming an important task for public health investigators, ecologists and parasitologists. Recently, this dynamic has stimulated research investigating the affects of ecosystem alterations on parasitism of keystone species. This study investigates environmental and anthropogenic impact on parasitism in populations of Alligator mississippiensis along coastal Louisiana wetlands over a three-year period. Due to the past hurricane activity in Louisiana over the last 5 years, alteration of Louisiana wetlands is threatening the host-parasite dynamic between Alligator mississippiensis and their helminth parasites. The disturbance of an ancient co-evolved relationship can be detrimental for the host, increasing susceptibility to various pathogens and causing premature mortality. To understand how ecosystem disturbances are affecting alligators, the gastrointestinal tract will be collected annually during the Louisiana alligator harvest (n>20). Parasitism prevalence among size, gender, and location will be statistically analyzed to assess environmental and anthropogenic affects on host and ecosystem. Immunological and toxin assays from host will be analyzed to assess host immunity and toxin correlation to parasitism. Evaluating association between parasite quantity, immunocompetence, and toxin level will assist in identifying sub-groups that are more susceptible to ecosystem alteration. This information will be vital for local wildlife and wetland management agencies as they continue the wetland restoration process from past hurricane activity, and manage urbanization.















































































































































































































































































































































































































































































































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