While there are many more species of reptiles in the tropics than in temperate
latitudes, relatively little is known about the natural history of tropical species of
snakes. Even basic information, such as reproductive ecology and behavior, is lacking. Patterns of reproduction in tropical species differ from patterns in temperate...
Contemporary environmental change encompasses massive biodiversity loss and
increasing numbers of emerging diseases worldwide. As part of a global biodiversity
crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium
dendrobatidis is an emerging infectious pathogen prominently associated with many
declines. Chapter 1 reviews the past decade of research on this system...
Studies were conducted within a 12-mile radius of Camp Sherman, Oregon, in the Deschutes National Forest during the spring and summer of 1965 and the spring of 1966, with one follow-up visit in the summer of 1967. The feeding and foraging activities of Eutamias amoenus and Citellus lateralis were observed,...
The remodeling of the central nervous system (CNS) during metamorphosis in Drosophila melanogaster is a prime model system in which to study the genetic control of the sexual dimorphisms in the abdominal ganglion of the CNS. I have been using a P[tau-lacZ] enhancer trap line, 4.078, to label a segmentally...
Humans are increasing the scale and frequency of many natural disturbances, as well as adding novel disturbances to ecosystems. This thesis uses the arthropod community as a metric to examine the multi-trophic responses to disturbances in California grasslands. Chapter 2 explores how the long-term exclusion of native vertebrate herbivores has...
In animals, reproductive behaviors serve to attract individuals together during the
breeding season and to coordinate the behavioral and physiological states of individuals
so that mating can successfully occur. In snakes, the various reproductive behaviors
including courtship, mating, courtship inhibition, male combat and trailing are mediated
primarily by pheromones. Pheromones...
An investigation was made of the factors which cause differences in growth rates and transformation size of bullfrog tadpoles under natural conditions. Tadpoles and algal samples were collected from two.adjacent farm ponds of similar size during the eighteen months of the study. It was found that the tadpoles in one...
Volcanic activity during the Tertiary has long been held
responsible for the deaths and subsequent fossilization of the
vertebrate populations of the John Day region in Oregon. Oreodonts
as plains or savannah dwelling ruminant herbivores, were likely to
have been subject to potential exposure throughout their lifetime
to volcanic debris...
Hypotheses concerning relative costs of inbreeding and
outbreeding were evaluated for the harpacticoid copepod Tigriopus
californicus, which inhabits high intertidal tidepools. Field
studies indicate high variation in biotic and abiotic parameters
among pools. These findings coupled with previous information
about very low dispersal rates and local adaptations to individual
pools...