Calanoid copepod diet was investigated in Oregon coastal waters to determine
the trophic significance of phagotrophic protists as copepod prey within an ecosystem
where the microplankton biomass is typically dominated by large diatoms. Prior to and
during the 1991 upwelling season, clearance rates on phytoplankton and phagotrophic
ciliates were measured...
An inelastic scattering experiment was done in which 17-MeV
protons from the Oregon State University cyclotron were scattered
from ¹⁴N
and ¹⁵N gas targets. Angular distributions are shown for
the ground, 6.32-, 7.56-, 8.31-, and 8.57 -MeV states and the 5.3- and
7.2-MeV unresolved doublets of ¹⁵N, and for the...
Chemoreception is one of the dominant sensory modalities for many species of salamanders (reviewed in Chapter 2). At least seven of the ten currently recognized salamander families are known to respond to some sort of chemical cue. These responses are as varied as delaying hatching, seeking refuge, or initiating aggressive...
The majority of female animals are polyandrous: offspring within a single reproductive event are sired by more than one male. However, we lack a clear understanding of the ultimate causes of polyandry, and of the male reproductive strategies which have evolved in response to selection occurring after insemination. I addressed...
Sexual selection can influence the mating system of an organism through multiple mechanisms. These mechanisms result in variation in reproductive success among individuals, and include scramble competition, endurance rivalries, contests, mate choice and cryptic choice, and sperm competition. Understanding the mating system of a species requires the identification of which...
Animal signaling systems frequently utilize multiple traits to produce and transmit a signal. These system elements may span multiple levels of organization. Functional integration of these traits may be expected to generate concordance in evolutionary pattern among system elements, such that evolutionary change in one system component is correlated with...
Darwin devised the evolutionary theory of sexual selection to account for the manifold extravagances of courtship behaviors and displays. Mating interactions represent a major evolutionary process driving the elaboration, vibrancy, and peculiarity of these courtship traits. For my dissertation research, I strived to elucidate the dynamics that constitute the complex...
My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male...
Wavelet analysis is an analytical and modeling tool for optimizing sampling efficiency and accuracy, particularly in the context of designing long-term, large-scale monitoring plans. As a pattern analysis method that accommodates and preserves non-stationarity, wavelet analysis provides novel visualization and analytical capabilities for increased insight into interactions between multi-scalar heterogeneous...
My dissertation focuses on the evolutionary forces that have shaped the chemical signaling system of plethodontid salamanders. Pheromones mediate two phases of plethodontid reproduction: mate attraction prior to courtship and female persuasion during courtship. Substrate-borne chemical signals are believed to play an important role in mate attraction for these animals....