EDUCATION:

B.S., Biology, 1979, Central Missouri State University
M.S., Entomology, 1982, Iowa State University
Ph.D., Systematics & Ecology, 1989, University of Kansas

RESEARCH INTERESTS:

I am an insect ecologist, with a primary interest in insect dispersal and migration, at the levels of both the individual and the population. Characterizing insect movement patterns and behavior is critical to understanding the ecology of a pest species well enough to make predictions and to develop more effective pest and resistance management strategies. However, dispersal is one of the most difficult aspects of an insect's life history to study. I employ a combination of techniques in my research of insect movement including both direct and indirect strategies. Laboratory flight mills are used to study individual flight behaviors, and the intrinsic and extrinsic factors that generate interindividual variation. I use mark-release-recapture experiments to investigate short-range dispersal. For long-range movement, I employ molecular markers and population genetics analyses to obtain estimates of gene flow, an indirect measure of dispersal.

Current Projects:

1) A fundamental element of the current insect resistance management (IRM) strategy for European corn borer (ECB) on transgenic Bt corn is to closely monitor populations for increases in resistance. Currently, the appropriate spatial scale of a monitoring system is unknown, because the geographic size of local ECB populations and total populations is unknown. We are using microsatellite DNA markers and RFLP markers for the Bt-resistance candidate gene cadherin to measure gene flow spatially along transects through the central Corn Belt, and between years at a subset of locations. Combined results of spatial and temporal analyses will allow us to define the geographic size of ECB populations. Furthermore, this research will provide information on gene flow between populations, so that the rate of spread of any resistance that does develop can be predicted at a regional scale.

2) We are using an enrichment protocol to develop a large number of microsatellite markers for the western corn rootworm (WCR). Variability, Mendelian inheritance, ease of genotyping, and cross-reactivity with southern, northern, and Mexican corn rootworms are being tested. A subset of markers is being used to determine population genetic structuring of WCR across a wide geographic area in the northern and central US. Linkage maps of microsatellites and AFLP markers are being created and will be used in QTL analyses of WCR diapause.

3) We are developing a method for on-farm within-field mapping of ECB and corn rootworm damage that combines Bt/nonBt strip planting of corn with yield mapping. Our premise is that insect damage leading to yield reductions within nonBt strips can be identified through paired comparisons with yield data from undamaged isoline corn in flanking Bt strips. Our method will allow growers to determine which spatial patterns of damage are stable over years, both between and within fields. Prescription planting of Bt corn will increase grower profits and slow development of insect resistance to the Bt toxin.

4) We are using mark-recapture techniques to quantify moth propensity to colonize nearby plots of wheat after emergence in a corn field, and to examine the influence of pheromone, plant density, and distance from the emergence location on ECB acceptance of these plots as aggregation sites. Understanding this behavior will have implications for IRM because adult dispersal patterns directly affect gene exchange. We hope eventually to learn enough to manipulate ECB spatial aggregations, which will be critical in attempts to mitigate Bt resistance by attracting susceptible moths to (or releasing and holding them in) areas where resistance has been detected.

Other Research Interests: I have research experience and ongoing interests in: 1) The molecular structure, sequences, and evolutionary relationships of insect vitellogenins and other yolk proteins, and of vitellogenin receptors and other members of the LDL receptor superfamily. 2) Sexual selection and courtship behavior in insects. 3) Selective advantages of sex-linked pre-reproductive isolating mechanisms in animals, especially Lepidoptera. 4) The use of cuticular hydrocarbon profiles for estimating insect age. 5) Boll weevil ecology, and insect pests of cotton.

CURRENT LAB MEMBERS:

Kyung Seok Kim - Postdoctoral Research Associate. Molecular ecology of boll weevil, European corn borer, and western corn rootworm.

Brendon Reardon - PhD student. European corn borer dispersal, choice of aggregation sites, and sperm precedence.

Selected Publications:

Kim, K. S. and T. W. Sappington. 2004. Isolation and characterization of polymorphic microsatellite loci in the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae). Mol. Ecol. Notes (In Press).

Sappington, T. W., A. D. Brashears, M. N. Parajulee, S. C. Carroll, M. D. Arnold, and R. V. Baker. 2004. Boll weevil (Coleoptera: Curculionidae) survival through cotton gin trash fans. J. Econ. Entomol. (In Press).

Sappington, T. W., A. D. Brashears, M. N. Parajulee, S. C. Carroll, M. D. Arnold, and R. V. Baker. 2004. Boll weevil (Coleoptera: Curculionidae) survival through cotton gin trash fans. J. Econ. Entomol. (In Press).

Sappington, T. W., A. D. Brashears, M. N. Parajulee, S. C. Carroll, M. D. Arnold, and R. V. Baker. 2004. Boll weevil (Coleoptera: Curculionidae) survival through the seed cotton cleaning process in the cotton gin. J. Econ. Entomol. (In Press)

Sappington, T. W., A. D. Brashears, M. N. Parajulee, S. C. Carroll, M. D. Arnold, J. W. Norman Jr., and A. E. Knutson. 2004. Potential for transport of boll weevils (Coleoptera: Curculionidae) to the cotton gin within cotton modules. J. Econ. Entomol. 97: 934-940.

Kim, K. S. and T. W. Sappington. 2004. Genetic structuring of boll weevil populations in the U.S. based on RAPD markers. Insect Mol. Biol. 13: 293-303.

Kim, K. S. and T. W. Sappington. 2004. Boll weevil (Anthonomus grandis, Boheman) (Coleoptera: Curculionidae) dispersal in the southern United States: evidence from mitochondrial DNA variation. Environ. Entomol. 33: 457-470.

Sappington, T. W. 2002. Mutual interference of pheromone traps within trap lines on captures of boll weevils (Coleoptera: Curculionidae). Environ. Entomol. 31: 1128-1134.

Sappington, T. W. 2002. The major yolk proteins of higher Diptera are homologs of a class of minor yolk proteins in Lepidoptera. J. Mol. Evol. 55: 470-475.

Sappington, T. W. 2002. Efficacy of the organic-certified insecticide Diatect II against the boll weevil (Anthonomus grandis) in cotton. Pest Management Sci. 58: 1038-1042.

Sappington, T. W., S. M. Greenberg, and R. A. Tisdale. 2001. Location of beet armyworm (Lepidoptera: Noctuidae) egg mass deposition within canopies of cotton and pigweed. Environ. Entomol. 30: 511-516.

Sappington, T. W. and D. W. Spurgeon. 2000. Variation in boll weevil captures in pheromone traps (Coleoptera: Curculionidae) arising from wind speed moderation by brush lines. Environ. Entomol. 29: 807-814.

Sappington, T. W. and A. S. Raikhel. 1998. Insect vitellogenins and vitellogenin receptors. Insect Biochem. Mol. Biol. 28: 277-300.

Sappington, T. W. and A. S. Raikhel. 1998. Ligand-binding domains in vitellogenin receptors and other LDL-receptor family members share a common ancestral ordering of cysteine-rich repeats. J. Mol. Evol. 46: 476-487.

Sappington, T. W., V. A. Kokoza, W. L. Cho, and A. S. Raikhel. 1996. Molecular characterization of the mosquito vitellogenin receptor reveals unexpected high homology to the Drosophila yolk protein receptor. Proc. Nat. Acad. Sci. USA 93: 8934-8939.

Sappington, T. W., A. R. Hays, and A. S. Raikhel. 1995. Mosquito vitellogenin receptor: purification, developmental and biochemical characterization. Insect Biochem. Molec. Biol. 25: 807-817.

Sappington, T. W., H. W. Fescemyer, and W. B. Showers. 1995. Lipid and carbohydrate utilization during flight of the migratory moth, Agrotis ipsilon (Lepidoptera: Noctuidae). Archiv. Insect Biochem. Physiol. 29: 397-414.

Sappington, T. W., and W. B. Showers. 1992. Forum: Reproductive maturity, mating status, and long-duration flight behavior of Agrotis ipsilon (Lepidoptera: Noctuidae), and the conceptual misuse of the oogenesis-flight syndrome by entomologists. Environ. Entomol. 21: 677-688.

Sappington, T. W., and W. B. Showers. 1991. Implications for migration of age-related variation in flight behavior of Agrotis ipsilon (Lepidoptera: Noctuidae). Ann. Entomol. Soc. Am. 84: 560-565.

Sappington, T. W., and O. R. Taylor. 1990. Developmental and environmental sources of pheromone variation in Colias eurytheme butterflies. J. Chem. Ecol. 16: 2771-2786.

Sappington, T. W., and O. R. Taylor. 1990. Genetic sources of pheromone variation in Colias eurytheme butterflies. J. Chem. Ecol. 16: 2755-2770.

Sappington, T. W., and O. R. Taylor. 1990. Disruptive sexual selection in Colias eurytheme butterflies. Proc. Nat. Acad. Sci. USA 87: 6132-6135.