The 2000 Summer Research Fellows at Davidson are listed below, along with the name and abstract of their research project and the name of their faculty mentors:
Ross
Cocklin
Dr. Michael E. Dorcas, mentor
Herpetological Surveys of Hanging Rock and Crowder's Mountain State Parks
Over a ten week period, we conducted herpetological surveys at both Crowders Mountain and Hanging Rock State Parks. Our objectives were to 1) determine the species diversity and relative abundance of reptiles and amphibians at both of the parks, 2) develop a historical database accounting for past and present records that can be used by the state park system for conservation, 3) increase interest in reptiles and amphibians among park staff and the public, and 4) provide a solid foundation for future research by Davidson College students and others. We made more than 50 observational records of 17 different species of amphibians and reptiles from Crowders Mountain State Park. With the help of John Sealy (Appalachian State University), we generated an amphibian and reptile database for Hanging Rock State Park that contains more than 170 records of 32 different species. All observations have GPS coordinates allowing for the development of maps demonstrating the distribution of amphibians and reptiles within the parks. Awareness by the public was increased by presenter at the Crowders Mountain Annual Reptile and Amphibian Day, which drew a crowd of over 200 people and by an article by the Charlotte Observer documenting our study.
Courtney
S. Ewart
Dr. David Wessner, mentor
Molecular Analysis of the Mouse Hepatitis Virus Receptor, MHVR
To initiate
a productive infection, a viral particle generally must bind to a host
cell, penetrate the cellular membrane, and undergo some type of uncoating
event, thereby exposing its genome to the host cell machinery. Investigations
of these initial events in a viral lifecycle, then, will augment our understanding
of viral pathogenesis and, potentially, provide insight into the development
of effective anti-viral therapies. Previously, the gene encoding MHVR,
the cellular receptor for mouse hepatitis virus,
was identified, sequenced, and characterized. To determine the molecular
basis of the virus:receptor interaction, we constructed a series of chimeric
recombinant receptor molecules. Analysis of these molecules indicated
that a defined region at the N-terminus of MHVR is crucial for virus binding
to and subsequent infection of host cells. The results, however, also
indicated that C-terminal regions of MHVR may influence virus binding
and/or infectivity. As part of this project, we have begun to further
investigate this finding. Various receptor constructs were cloned into
a mammalian expression vector. Sequence comparisons of these constructs
were completed and regions of difference were identified. We now are prepared
to use site-directed mutagenesis to alter these regions of interest in
the corresponding molecules. These constructs, then will be transfected
into a receptor-negative cell line and their ability to serve as receptors
for the virus will be determined. These studies will provide us with a
more detailed, molecular, understanding of the virus:cell interactions
and will further our overall understanding of the infection process.
David
Lamar, Suzanne Moore, and Annie Welsh
Dr. Mark Stanback, mentor
Nest site fidelity in Eastern Bluebirds: predator
vs. parasite avoidance
By nesting in cavities low to the ground, secondary cavity nesters increase the likelihood of detection by mammalian and reptilian predators. By reusing soiled nests, such birds presumably incur the costs of nest parasites. By experimentally varying these two factors, we tested the relative importance of each to nest site fidelity in Eastern Bluebirds. Previous research has demonstrated that Eastern Bluebirds avoid reusing soiled boxes (when provided with a second, clean box) but prefer to reuse successful nest boxes (if they are clean). With respect to nest height, bluebirds showed a significant preference for high (5 ft) vs low (4 ft) boxes for their first nests of the year, suggesting that they are sensitive to the vulnerability of their nest to predators. For second nests in 1999, we forced bluebirds to choose between their successful soiled box or a clean low box. If bluebirds are more sensitive to parasites than predators, one would expect birds to switch to clean low boxes. If birds are more sensitive to predation risk, they should reuse their soiled high nests. We found that bluebirds reused soiled high boxes significantly more often than they reuse soiled nests when given boxes of equal height. This suggests that both parasite and predator avoidance are relative to the quality of available nest sites.
Eastern Bluebirds as Environmental Indicators on North Carolina Golf Courses
Analysis of reproductive parameters of golf course nesting birds can provide valuable information on the biological effects of golfer and turf maintenance activities on course wildlife. Because eastern bluebirds (Sialia sialis) nesting on fairways feed their young on insects collected primarily on managed turf, they may be vulnerable to the chemicals used there. In 1999, we monitored 150 nestboxes in control habitat (hayfields and pastures) and 100 nestboxes on golf courses (25 on each of four courses) near Davidson, NC for first egg date, clutch size, hatching success, within-brood size disparity, nestling condition, and nest failure. We detected no significant differences in any of the above measures.
Mate Choice in Eastern Bluebirds: The Role of Condition
If female birds prefer mates of the highest genetic quality, but are constrained in their choice of partner by the choices of higher quality females, one would expect to observe a positive correlation between male and female condition within pairs. Alternatively, within-pair similarity could be due to the fact that paired birds live on the same territory and share parental duties. To address this, we measured eastern bluebird (Sialia sialis) condition during the chick-rearing phase using indices of current vs. past condition. Mass and hematocrit both reflect nutritional and physiological condition at the time of capture. Size-specific mass and bilateral asymmetry presumably reflect the condition of the bird during feather growth in the prior year. Mass and hematocrit showed significant correlations between male and female social mates. Feather-based indices showed no correlation. This suggests that much of the similarity of mated pairs may develop after pairing.
Christine
Larned
Dr. David Wessner, mentor
Development of Undergraduate DNA Sequencing Protocols
In recent
years, the importance of and interest in DNA sequencing has increased
dramatically. Many of the techniques required for such studies, though,
are costly,
Time-intensive, and/or involve the use of toxic reagents. As a result
of these constraints, few undergraduate students gain practical exposure
to these procedures. With recent advances in technology and methodologies,
however, it is possible to develop DNA sequencing protocols that amenable
to use in undergraduate courses.
As part of this project, we are developing such protocols. First, we have
developed a protocol for rapid DNA sequencing and electrophoresis using
the Novex QuickPoint system. Second, we have adapted a rapid, chemiluminescent
detection protocol to be used for the detection of DNA sequencing products.
Both of these protocols can be completed within the time constraints of
an ordinary laboratory class period, are relatively inexpensive, and do
not involve toxic reagents. As a result, we now can give our students
hands-on experience with these important procedures.
Shane
D. Lindsay
Dr. Michael E. Dorcas, mentor
Demography
and Habitat Associations of Pond Dwelling Turtles
in the Western Piedmont of North Carolina
Few studies have addressed intraspecific variation in life-history characteristics among habitats of varying quality. We used an extensive mark-recapture study to compare semi-aquatic turtle populations among twelve ponds with varying cattle impact in the vicinity of Davidson, NC. We compared turtles at a community level while testing for differences in morphology and reproduction among the ponds. We found considerable variation in species composition and relative abundances among the ponds. We also found that Kinosternon subrubrum (eastern mud turtles) morphology and egg size is inversely correlated with concentrations of nitrite/nitrate, phosphorus, pH, ammonia, and overall cattle impact. Chrysemys picta (painted turtles) morphology and egg size was not correlated with measured characteristics of water quality or with our cattle impact index. Other species captured in this study include Chelydra serpentina (snapping turtles), Trachemys scripta (sliders), and Sternotherus odoratus (musk turtles). While populations of these turtles were too small to allow statistical comparisons, we did document several new county records for these species.
2000 Summer Research Fellows at Davidson
Hughes Summer Research Fellows '97
