Bodega Marine Laboratory/Reserve
February 22-24, 2008 |
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Participant Abstracts
Gyne investment and implications for colony founding strategies in harvester ants
(genus Pogonomyrmex)
Brittany Enzmann
Department of Ecology and Evolutionary Biology
University of California, Los Angeles
Colony founding is a critical stage in social insect life history. In ants, workers provision future queens (gynes) that later mate, disperse, and use one of several strategies to found colonies. Reproduction thus involves individual gynes that found new colonies and the collective behavior of workers that invest colony resources into sexual production. Claustrality is a variable gyne characteristic directly linked to colony
investment. Fully claustral gynes are large and require many stored reserves to raise their first worker brood without foraging, while semi-claustral gynes are small and require fewer reserves as they forage
during colony initiation. In the harvester ant genus Pogonomyrmex, claustral, semi-claustral, and
facultative (both) variants exist across species. My project aims to determine the colony investment costs for producing these three gyne variants. Specifically, I will compare lipids, protein, carbohydrates, and metabolic rates and measure the expression of a storage protein (Hexamerin II) of gynes throughout
development. I will also perform a field supplementation experiment on a facultative species to assess the phenotypic plasticity of the trait and whether gyne claustrality is affected by resource quality. Specifically, lipids, protein, and Hexamerin II expression will be compared between colonies supplemented with protein resources, carbohydrate resources, both, and controls. Investigating proximate questions of investment and social control over claustrality will give insight on how its variation may have evolved and is maintained. It will also serve as a prime example of how a reproductive trait is implicated at both individual and colony levels in a social insect.
Ecological consequences of exposure to natural oil contamination: Population-level effects of the multidrug resistance mechanism
Heather M. Coleman
Bren School of Environmental Science and Management
University of California, Santa Barbara
Microbial metabolites of naturally occurring hydrocarbons, such as crude oil, are substrates of P-glycoprotein (P-gp) transport proteins. Given the abundance of life near areas of natural oil seepage, resident animals might be expected to suppress the toxicity of crude oil biodegraded water-soluble fractions (BWSF) using such transporters. Consistent with this hypothesis, our results indicate that the sea urchin,
Strongylocentrotus purpuratus, exhibits different levels of multidrug resistance transport activity as a
function of its habitat when exposed to BWSF and fluorescent calcein-AM. Embryos from control parents accumulated 1.7-fold more calcein, indicating a significantly (P < 0.001) lower multidrug efflux activity than embryos of animals collected from an oil seep. Furthermore, S. purpuratus exhibit similarly greater efflux activity (P < 0.001) in embryos from an oil seep when exposed to known synthetic inhibitors of both P-gp and multidrug resistance-associated protein (MRP): MK571, PSC833, musk xylene, and galaxolide.
Therefore, urchins that are pre-exposed to natural hydrocarbon contamination confer multiple types of xenobiotic resistance proteins to their progeny. Since there can be a significant energetic cost to production and storage of these proteins in eggs, a question raised by this finding is whether a population-level cost of this adaptive change in transporter activity exists. Future research will examine the reproductive costs
(via the gonadosomatic index) of adaptation to oil seeps and the energetic costs of accumulating
transporters in eggs. Incorporating this information into larger scale dynamic energy models will provide insight into the population-level effects of transporter-mediated adaptation to contaminants.
Living in the margins? An investigation of interior Late and Contact period Chumash residential sites on Limuw (Santa Cruz Island), California
Elizabeth A. Sutton
Department of Anthropology
University of California, Santa Barbara
Archaeologists studying the indigenous peoples living in the Santa Barbara Channel Region, known
collectively today as the Chumash, have relied on two types of sources to reconstruct Late and Contact period Chumash settlement systems: 1) the incomplete and highly conflicting reports of sixteenth and
seventeenth century seafaring Spanish explorers and 2) the late nineteenth and early twentieth century
ethnographic accounts of Chumash consultants. While this information has proven to be extremely
valuable in providing a general understanding of Chumash lifeways, it has been too convenient to focus research on the highly visible villages described in these accounts and reconstruct Chumash settlement patterns based solely on data from these large sites. While these accounts portray the Chumash of the Channel Islands as living in large, densely populated coastal villages during the Contact period, recent investigations have revealed two small interior residential sites on Santa Cruz Island that have been dated to the Late and Contact periods. The existence of these sites calls into question the accuracy of current models of Island Chumash settlement patterns which dismiss the possibility of residential settlement
during these time periods in the “marginal” interior areas of the Channel Islands, and in addition may
represent an exception to the anthropological correlation of complex hunter-gatherers with an aggregated, sedentary settlement pattern. Further research at these sites will attempt to refine site occupation
chronology and determine seasonality of use. An attempt to locate and document other interior residential sites will also be made.
Early maritime hunter-gatherer occupation and the initial human migration into the New World, Santa Cruz Island, California
Amy E. Gusick
Department of Anthropology
University of California, Santa Barbara
Although we have made much progress towards a better understanding of Pacific maritime cultures, little evidence has been recovered to support a coastal route for the initial human migration into the New World. Despite this hypothesis having received widespread support in recent years, more definitive research that supports a coastal migration must be conducted in order to solidify it as a viable alternative to the antiquate, ice-free corridor migration hypothesis. Santa Cruz Island represents a key piece of this research. The first humans migrating into the Americas could have utilized Santa Cruz Island for its environmental conditions (marine productivity and fresh water sources), morphological features (rock shelters and accessibility to marine resources), accessibility by watercraft and close proximity to the mainland. In fact, hundreds of cultural deposits have been identified on Santa Cruz Island; however, none of them are Pleistocene in age, placing them out of the possibility of being related to a Pleistocene coastal migration. My research focuses on the identification of cultural deposits located on Santa Cruz Island that can be considered to support a coastal route for the initial human migration into the New World. By utilizing settlement and subsistence patterns identified at early sites located on adjacent islands, I have located five cultural deposits that may inform our understanding of the role that Santa Cruz Island played in the initial peopling of the New World.
Relative Importance of Plant Resources in Prehistoric Diets: Archaeological Evidence from
Santa Cruz Island
Kristina M. Gill
Department of Anthropology
University of California, Santa Barbara
Although many archaeological investigations have been conducted on Santa Cruz Island, these studies tend to focus on coastal areas, with an emphasis placed on the study of faunal remains in prehistoric diet
reconstruction. Relatively little work has been conducted in interior areas, with almost no attention placed on the role of plant remains in subsistence strategies. Ethnographic information indicates that plants were
integral to Chumash culture, not only for subsistence, but also for medicinal, ceremonial, and functional
purposes. Due to the low visibility of plant remains in archaeological sites, and the time-consuming
analysis required to study them, we know very little about prehistoric usage of plants in the Santa Barbara Channel area. With this in mind, several archaeological sites on Santa Cruz Island have been selected for further investigation. These include Middle and Late Holocene sites located in the Central Valley and a bedrock mortar complex located on the northern ridge, near Diablo Peak. An analysis of these sites, and the plant remains from them, will provide a better understanding of not only prehistoric subsistence
practices, but also ceremonial, medicinal, and functional practices related to plants.
Non-invasive Monitoring of Recovering Channel Island fox (Urocyon littoralis) Populations
Melissa M. Gray
Department of Ecology and Evolutionary Biology
University of California, Los Angeles
Genotyping scat samples has emerged as a promising population monitoring tool for many
organisms. This method was applied to recovering populations of Channel Island fox (Urocyon
littoralis). The island fox, endemic to the Channel Islands off the coast of Southern California,
declined by over 95% in the 1990s due to predation by golden eagles (Aquila chrysaetos). This was the impetus for listing the island fox as federally endangered. Since then, intensive removal of golden eagles has taken place, and captive breeding has increased island fox populations to the point where release back into the wild has begun. The success of wild population recovery is being tracked via population monitoring, which so far has been accomplished by costly and labor intensive live-trapping and radiotelemetry
methods. The feasibility of monitoring the island fox populations long term by means of non invasive
sampling of scat was explored. Appropriate study sites were selected on Santa Cruz Island, which currently has a population of 150+ individuals and on San Miguel Island, which has a population of about 50
individuals. Comparisons with data from radiotelemetry, live-trapping, and genotypes from blood samples have served as a means to evaluate the effectiveness of fecal genotyping as a population monitoring tool. The effectiveness of these methods is currently being evaluated and, if proven competent, could result in a more precise and cost-effective means to monitor the population for the long term, which will enable
managers to better determine whether island fox recovery is successfull.
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