East Carolina University : Research and Creative Achievement Week 2012
Do male Eastern bluebirds adjust their level of nest defense in relation to the color of their mate's clutch?, Kimberly Wade, Susan B. McRae, East Carolina University, Greenville, NC 27858 Recent studies investigating the function of blue coloration in birds’ eggs have suggested that females in better condition may advertise this by depositing more pigment in their eggshells. We conducted an experimental study of Eastern bluebirds (Sialis sialis) to test whether male bluebirds are able to judge female quality by egg color and adjust their investment accordingly. We selected synchronous nests with similar clutch sizes, and swapped clutches with light blue eggs with clutches having brighter blue eggs (N=14). Egg color was measured in the field with a spectrophotometer. After the eggs hatched, we swapped the chicks back to their biological parents' nests to disassociate the male parents response to signals from the chicks. We also monitored 22 control nests whose eggs were not swapped for comparison. To assay parental nest defense, at both the egg and nestling stages, we presented on sequential days models of a cowbird (a threat mostly to eggs), a crow (a threat to both nest and parents), and a snake (a threat to eggs and chicks). We then scored both the male's and the female's responses individually. A relative measure of parental condition will be based on weight, tarsus and wing length. In general, avian nest defense increases over the course of the nesting period. Thus, we expect the level of nest defense to increase during the nestling period except in the case of the cowbird, that is not a threat to older nestlings. If males respond to the color of the clutch, then we expect that during the egg stage, the experimental males that received brighter blue eggs will have higher aggressive response times for all models than those that received the lighter eggs. This effect may be reduced during the nesting stage after swapping the chicks back to their original parents. We expect the intensity of maternal nest defense to correlate with female condition measures. Duration and intensity of parental responses will be compared between experimental and control nests, and between nest stages and model types, to elucidate whether or not males use egg color to inform their effort in nest defense.
UP55
The Integration of GIS and Ecology: Examining Plant Density of Packera tomentosa (Asteraceae), J.C. Paxton, L.D. Leverett, C.L. Jolls, Department of Biology, East Carolina University, Greenville, NC 27858 Ecology is the scientific study of the distribution and abundance of organisms, often in relation to chemical, physical, and biotic factors. Geographic Information System (GIS) techniques allow us to visualize these distributions and spatial relationships of organisms on a map. These techniques include map modification through computer software, such as ArcGIS, that allow alteration, storing, querying, and analyzing geospatial data. There are many advantages of integrating GIS and ecology, including the ability to visualize spatial distributions of organisms and then ask relevant questions. At East Carolina University's West Research Campus (WRC), a 25 m by 50 m plot with 5 m2 subplots was established to examine the flowering plant Packera tomentosa and its spatial distribution. P. tomentosa, woolly ragwort, is a native member of the sunflower family (Asteraceae) found in the southeastern coastal plain of the United States. We used the ArcMap 10 program within the ArcGIS software (ESRI, Redlands, CA), provided by ECU, with an orthographic picture of the site location at WRC, to create maps of the sampling plot. GPS coordinates of the sampling plot provided the groundwork of the 5 m2 grid system used to visualize the density of P. tomentosa. Based on the maps created through ArcMap 10, we hypothesized a potential trade-off between total plant density and the proportion of plants flowering. The map suggested that 5 m2 plots with high numbers of plants showed lower 222
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