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Welcome to the University Archives electronic records community. The University Archives community in Scholars’ Bank is for university records in digital form. The material contained in Scholars’ Bank represents a small portion of the institutional records housed in University Archives. If you are interested in other historic or contemporary records not seen here, please contact Special Collections and University Archives at spcarref@uoregon.edu or 541-346-3068.
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Browsing University Archives by Subject "Zoology"
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Item Open Access Larval Biology and Estuarine Ecology of the Nemertean Egg Predator Carcinonemertes errans on the Dungeness Crab, Cancer magister(University of Oregon, 2011-09) Dunn, Paul Hayven, 1981-The nemertean worm Carcinonemertes errans is an egg predator on the Dungeness crab, Cancer magister, an important fishery species along the west coast of North America. This study examined the estuarine distribution and larval biology of C. errans. Parasite prevalence and mean intensity of C. errans infecting C. magister varied along an estuarine gradient in the Coos Bay, Oregon. Crabs nearest the ocean carried the heaviest parasite loads, and larger crabs were more heavily infected with worms. Seasonal infection patterns were seen at some sites within the bay. Crabs from coastal waters carried significantly more worms than did crabs from the bay, suggesting that the estuary may be acting as a parasite refuge for estuarine crabs. In laboratory experiments, C. errans all died in salinities below 10 within 6 days, but C. errans showed some tolerance to salinities 20 and above. These results suggest that salinity alone does not likely account for the estuarine gradient of C. errans in Coos Bay. Larvae of C. errans raised from hatching never settled in the laboratory. Competent larvae taken in plankton tows were morphologically distinct from larvae raised in laboratory cultures and did settle successfully on C. magister under laboratory conditions. Initial settlement was reversible within a 24-hour window. After 48 hours, a non-reversible metamorphosis occurred wherein worms lost one pair of eyes and the propensity to swim. In field settlement experiments, C. errans was capable of infecting hosts from the water column and preferred to settle on crabs already infected with juvenile worms, although this preference was density dependent. In monthly plankton tows, larvae of C. errans were found only between August and November, suggesting a long larval life for this species. Larvae did not feed under laboratory conditions, nor did they absorb dissolved organics. When exposed to a natural angular light distribution, larvae of C. errans were rarely photopositive. Larvae were most sensitive to blue-green light. Low intensity light invoked a photonegative response. Larvae were geopositive at hatching but geonegative thereafter.Item Open Access The ranging behavior of bonobos in the Lomako Forest(University of Oregon, 2011-06) Waller, Michel Tyler, 1973-The ranging behavior of an animal can reveal much about the social and ecological conditions it faces. Food availability, feeding competition, population pressures, metabolic requirements and human influences can all influence the ranging behavior of individuals. For modern humans, the manner in which we move about our world is limited only by access to technology and other cultural factors. Of course, it has not always been that way. Based on recent fossil discoveries, our earliest bipedal ancestors more closely resembled the living great apes in morphology. Consequently, studies of great ape behavior have been used to reconstruct scenarios of early hominin behavior. And while much has been written about chimpanzee ( Pan troglodytes ) ranging in this regard, less is known about bonobos (Pan paniscus ). Along with chimpanzees, bonobos are our closest phylogenetic relative, existing today as a descendant of a common ancestor the Homo and Pan genera shared sometime around six million years ago. Despite their close taxonomic relationship, however, there are a variety of behavioral differences between bonobos and chimpanzees. The aim of this dissertation is to better understand these differences within the context of ranging and social behavior and apply the results to models of early hominin behavior. More specifically, I used a Geographic Information Systems (GIS) approach to examine general bonobo ranging data, the differences in ranging behavior between males and females, and the manner in which neighboring groups interact. Compared with chimpanzees, bonobos at Lomako range over a much smaller total area, are not territorial, and differ in the composition of social parties. In general, female bonobos are more gregarious and cohesive, moving in semi-stable groups I call "cliques", while males are less aggressive and more likely to move independently. These results likely reflect the high levels of food availability for bonobos at Lomako, reducing the level of feeding competition, and emphasizing social and mating strategies in group formation. Consequently, the spectrum of potential early hominin ranging behavior must be expanded from the current chimp-centric perspective.Item Open Access Settlement Preference and the Timing of Settlement of the Olympia Oyster, Ostrea lurida, in Coos Bay, Oregon(University of Oregon, 2011-09) Sawyer, Kristina M., 1985-In the Pacific Northwest, populations of the Olympia oyster, Ostrea lurida, were once decimated by overharvesting and natural disasters. Their full recovery may now be limited by availability of hard substrata for larval settlement. I studied the timing of settlement and larval preferences for commonly available substrata, including conspecifics and the shells of Pacific oysters, Crassostrea gigas, which are often provided in restoration efforts. Settlement occurred from August-December with a peak in October. I found no significant settlement differences between live and dead oysters or between shells of Olympia or Pacific oysters. There was significantly higher settlement on bottoms of horizontal substrata than on tops. In the laboratory, larvae showed no clear preferences among various hard substrata. This lack of settlement preference has positive implications for restoration projects, since Pacific oyster shell is much easier to obtain and seems to be no less beneficial than the shells of conspecifics.