Northern Arizona University

My research and scholarship efforts at Northern Arizona University have developed in six major directions, all of which are extensions of my fundamental research goals. These goals are to understand: (1) the processes by which genetic variation in maintained in natural populations, (2) the genetic and environmental bases for the expression of sexual phenotype, (3) how selection can be measured in nature, and (4) how mating systems and alternative mating strategies evolve.

The first project involves investigation of expression of adult phenotype and population sex ratio in marine isopods, Paracerceis sculpta (NSF grant DEB-9726504). This project is an extension of my dissertation research and has been supported by NSF since 1984, six years before I arrived at NAU. The goal of this project is to understand the genetic and environmental mechanisms that maintain phenotypic variability in natural populations, and that allow alternative male mating strategies to persist in nature. All of my publications on P. sculpta (see CV) are part of this research. In future years, I plan to specifically investigate variation in the genetic factors that cause sex ratio biases in the natural population, as well as explore the effects of predation on the character of breeding aggregations.

The second project involves my continuing collaboration with Michael J. Wade at Indiana University. We are extending the theoretical principles developed in our book entitled "Mating Systems and Strategies" published by Princeton University Press in 2003. This book outlines a novel statistical approach for measuring the intensities of natural and sexual selection in nature. This approach provides new insights into why sexual selection is such a powerful evolutionary force, and it provides unique explanations for observed variation in mating systems and alternative mating strategies for all sexually reproducing organisms.

The third project is an NSF Research Experience for Undergraduates (REU) Site Program in Neural and Behavioral Sciences, for which I am Co-PI and director (NSF grant DBI-0243914; Virginia Blankenship, Co-PI, Department of Psychology). This project has received continuous funding since 1992, and provides summer research internships for 8 undergraduates from across the country. My portion of the project involves investigation of sex-linked genetic markers that are useful in documenting sex change in marine isopods. In future years, I plan to use these and other genetic markers to investigate patterns of sperm utilization in female isopods when mated by males of different adult phenotypes.

This faculty member is also a mentor in the NSF IGERT graduate training program: NAU’s IGERT PhD program seeks to identify key links between genes and the environment and is designed to train exceptional graduate students in molecular genetics, environmental sciences, and spatio-temporal modeling.

I am interested in exploring methods for estimating the intensity and form of genetic interactions within and among species from, individual to ecosystem scales. I am also interested in exploring statistical approaches for estimating how and to what degree individuals, species and communities may become genetically and phenotypically distinct.

My current projects investigate (1) the relative influences of social and sexual selection via indirect genetic effects (IGEs) on the evolution of cannibalistic behavior and body size, isopod crustaceans, (2) genetic interactions influencing the expression of parental care in sea spiders, leeches and syngnathid fish, and (3) estimates of community heritability and interspecific indirect genetic effects (IIGEs) for arthropod communities inhabiting cottonwood trees.

Three morphs of a single species of isopod