- Author: Kathy Keatley Garvey
The seminar takes place from 12:10 to 1 p.m. in 122 Briggs Hall. Host is Professor Greg Lanzaro of the Department of Pathology, Microbiology and Immunology, UC Davis School of Veterinary Medicine.
“The red imported fire ant (Solenopsis invicta) is an invasive pest insect in the United States and several other regions of the Pacific Rim that is native to South America,” Ross said. “Genetic data were used to trace the routes of colonization of this ant; the founders of the U.S. population appear to have originated in the Mesopotamia floodplain region of northern Argentina, and the southeastern U.S. population evidently served as the source of colonists in the more recent invasions of Pacific Rim regions.”
“Extensive genetic variation was lost during colonization of the United States, one manifestation of which was a striking increase in the production of sterile diploid males. Other changes in the southern U.S. population, including alteration in basic features of colony social structure, appear to be related to environmental factors such as the increased population densities in the invasive range.”
Ross said that two distinct social forms exist in Solenopsis invicta; the forms are characterized by fundamental differences in colony social organization and life history features. “This intraspecific social polymorphism is genetically determined, and its presence has implications for patterns of gene flow and forms of selection in this ant. Although very distinctive in some features of their social and reproductive biology, the two social forms evidently are linked by extensive gene flow mediated by males mating with queens of the alternate form.”
Ross received his bachelor’s degree in biology from Trinity University, San Antonio, Texas, in 1977, and his master’s degree in entomology from the University of Arizona in 1979. He received his doctorate in entomology in 1982 from Cornell University.
“My research interests focus on the evolutionary, population, and behavioral genetics of social insects,” Ross said. “My work involves analyses of genetic variation at differing spatial scales and taxonomic levels and in a diversity of organisms, primarily fire ants. Problems addressed include identifying reproductive isolating mechanisms in social insects, estimating levels of gene flow and selection, determining breeding and genetic structures within insect societies, and using phylogenetic analyses to trace patterns of evolution in mating systems and social behavior. I also pursue molecular phylogenetic analyses of major genes that regulate social organization in various social insects. The common theme of my work is to understand in broad terms how the major forces of evolution (selection, drift, recombination, migration) interact to mold properties of the social organization and breeding biology of social insects.”
He has published his work in Molecular Ecology, Science Express, Behavioral Ecology and Sociobiology, Proceedings of the Royal Society of London, Genetics, Zoologica Scripta, among other publications.
His seminar is scheduled to be video-taped for later posting on UCTV.
Pitts, J. P., J. V. McHugh, and K. G. Ross. 2005. Cladistic analysis of the fire ants of the Solenopsis saevissima species-group (Hymenoptera: Formicidae). Zoologica Scripta 34: 493-505. PDF file
Ross, K. G. and D. D. Shoemaker. 2005. Species delimitation in native South American fire ants. Molecular Ecology 14: 3419–3438. PDF file
Krieger, M. J. B. and K. G. Ross. 2005. Molecular evolutionary analyses of the odorant-binding protein gene Gp-9 in fire ants and other Solenopsis species. Molecular Biology and Evolution 22: 2090–2103. PDF file
Shoemaker, D. D., C. J. DeHeer, M. J. B. Krieger, and K. G. Ross. 2006. Population genetics of the invasive fire ant Solenopsis invicta (Hymenoptera: Formicidae) in the United States. Annals of the Entomological Society of America 99: 1213-1233. PDF file
Giron, D., K. G. Ross, and M. R. Strand. 2007. Presence of soldier larvae determines the outcome of competition in a polyembryonic wasp. Journal of Evolutionary Biology 20: 165-172. PDF file
Gotzek, D. and K. G. Ross. 2007. Genetic regulation of colony social organization in fire ants: an integrative overview. Quarterly Review of Biology 82: 201-226. PDF file