Ecology, genetics and physiology of insect vectors

Summary

Principal Investigator: ELLIOT SCOVILLE KRAFSUR
Abstract: [unreadable] DESCRIPTION (provided by the applicant): Tsetse flies, Glossina spp., are obligate blood feeders and the vectors in Africa of the trypanosomes that cause sleeping sickness in people and 'nagana' in cattle. More than 60 million people are at risk from human sleeping sickness and severe epidemics occur in many parts of Africa. Animal trypanosomiasis prevents the use of domestic animals for agriculture in c.1 1.5 million km2 of sub-Sahara Africa, thus representing an enormous barrier to agricultural and economic development. The distribution of tsetse arises from interactions among historic events, tsetse dispersal capacity, natural barriers to dispersal, host distributions, climate, and adaptation to prevailing conditions. Among these factors, it was shown that tsetse distribution and abundance are most strongly correlated with temperature and saturation deficit. Moreover, most tsetse fly populations were shown to be strongly differentiated genetically. Because of these preliminary data and because tsetse populations are distributed discontinuously, the likelihood exists of genetic adaptation to local conditions. Do tsetse responses to temperature and water stress correspond to environmental variation in temperature and saturation deficit? Does genetic differentiation among populations correspond with differential responses of populations to temperature and water stress? It is important to answer these and related questions to deploy effectively area-wide control measures such as the sterile insect technique. We now propose to combine molecular techniques, physiological measurements, satellite data and ecological theory to address key questions about the genetics, physiology and geographical distribution of G. morsitans centralis, G. m. morsitans, and G. pallidipes in East and southern Africa. By adopting an integrated approach to understanding the distribution of tsetse in these regions, we shall achieve a comprehensive picture of tsetse fly adaptation to its environment, rates of gene flow (hence dispersal), and predictive models of distribution and abundance.
Funding Period: 2002-09-30 - 2008-03-31
more information: NIH RePORT

Top Publications

  1. pmc Tsetse genetics: contributions to biology, systematics, and control of tsetse flies
    R H Gooding
    Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada
    Annu Rev Entomol 50:101-23. 2005
  2. pmc New polymorphic microsatellites in Glossina pallidipes (Diptera: Glossinidae) and their cross-amplification in other tsetse fly taxa
    J O Ouma
    Department of Entomology, Iowa State University, Ames, IA 50011 3222, USA
    Biochem Genet 44:471-7. 2006
  3. ncbi Variation in scorpion metabolic rate and rate-temperature relationships: implications for the fundamental equation of the metabolic theory of ecology
    J S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
    J Evol Biol 20:1602-12. 2007
  4. pmc Critical thermal limits depend on methodological context
    John S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, Republic of South Africa
    Proc Biol Sci 274:2935-42. 2007
  5. ncbi Thermal tolerance in a south-east African population of the tsetse fly Glossina pallidipes (Diptera, Glossinidae): implications for forecasting climate change impacts
    John S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
    J Insect Physiol 54:114-27. 2008
  6. pmc Structure of some East African Glossina fuscipes fuscipes populations
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
    Med Vet Entomol 22:222-7. 2008
  7. pmc Tsetse flies: genetics, evolution, and role as vectors
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, IA 50011, USA
    Infect Genet Evol 9:124-41. 2009
  8. pmc Glossina swynnertoni (Diptera: Glossinidae): effective population size and breeding structure estimated by mitochondrial diversity
    J G Marquez
    Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
    Bull Entomol Res 96:353-60. 2006
  9. pmc Patterns of genetic diversity and differentiation in the tsetse fly Glossina morsitans morsitans Westwood populations in East and southern Africa
    J O Ouma
    Department of Entomology, Iowa State University, Ames, Iowa 50011 3222, USA
    Genetica 130:139-51. 2007
  10. pmc Shared microsatellite loci in Glossina morsitans sensu lato (Diptera: Glossinidae)
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, Iowa 50011 3222, USA
    J Med Entomol 43:640-2. 2006

Scientific Experts

Detail Information

Publications21

  1. pmc Tsetse genetics: contributions to biology, systematics, and control of tsetse flies
    R H Gooding
    Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9 Canada
    Annu Rev Entomol 50:101-23. 2005
    ..Here we review tsetse genetics from organismal and population points of view and identify some research needs...
  2. pmc New polymorphic microsatellites in Glossina pallidipes (Diptera: Glossinidae) and their cross-amplification in other tsetse fly taxa
    J O Ouma
    Department of Entomology, Iowa State University, Ames, IA 50011 3222, USA
    Biochem Genet 44:471-7. 2006
    ..3 +/- 5.5). Averaged across loci, observed heterozygosity was 0.581 +/- 0.209, and expected heterozygosity was 0.619 +/- 0.181. Cross-species amplifications of the G. pallidipes loci in other tsetse fly taxa are reported...
  3. ncbi Variation in scorpion metabolic rate and rate-temperature relationships: implications for the fundamental equation of the metabolic theory of ecology
    J S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
    J Evol Biol 20:1602-12. 2007
    ....
  4. pmc Critical thermal limits depend on methodological context
    John S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, Republic of South Africa
    Proc Biol Sci 274:2935-42. 2007
    ..These effects are explained by limited plasticity of CTLs in this species over short time scales. The results of the present study have broad implications for understanding temperature tolerance in these and other terrestrial arthropods...
  5. ncbi Thermal tolerance in a south-east African population of the tsetse fly Glossina pallidipes (Diptera, Glossinidae): implications for forecasting climate change impacts
    John S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
    J Insect Physiol 54:114-27. 2008
    ....
  6. pmc Structure of some East African Glossina fuscipes fuscipes populations
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
    Med Vet Entomol 22:222-7. 2008
    ..A first approximation of relative effective population sizes was Uganda > CAR-lab > Kenya. It was concluded that the structure of G. f. fuscipes populations in East Africa is localized...
  7. pmc Tsetse flies: genetics, evolution, and role as vectors
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, IA 50011, USA
    Infect Genet Evol 9:124-41. 2009
    ..Spatially and genetically representative sampling of both trypanosome species and strains and their Glossina vectors is a major barrier to a comprehensive understanding of their mutual relationships...
  8. pmc Glossina swynnertoni (Diptera: Glossinidae): effective population size and breeding structure estimated by mitochondrial diversity
    J G Marquez
    Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
    Bull Entomol Res 96:353-60. 2006
    ..The mean rate of gene flow was estimated to be approximately 5+/-1 reproducing females per generation but inflated because of mutation-drift disequilibrium arising from likely earlier bottlenecks...
  9. pmc Patterns of genetic diversity and differentiation in the tsetse fly Glossina morsitans morsitans Westwood populations in East and southern Africa
    J O Ouma
    Department of Entomology, Iowa State University, Ames, Iowa 50011 3222, USA
    Genetica 130:139-51. 2007
    ..GST among populations was 0.23 for microsatellite loci and 0.40 for mitochondria. The F, G and R statistics indicate highly restricted gene flow among G. m. morsitans populations separated over geographic scales of 12-917 km...
  10. pmc Shared microsatellite loci in Glossina morsitans sensu lato (Diptera: Glossinidae)
    E S Krafsur
    Department of Entomology, Iowa State University, Ames, Iowa 50011 3222, USA
    J Med Entomol 43:640-2. 2006
    ..87, close to the theoretic maximum value. All evidence suggests longstanding and complete reproductive isolation in nature among the sibling species. They should be elevated to specific rank...
  11. ncbi North American face flies Old World origins: mitochondrial evidence
    M A Cummings
    Department of Entomology, Iowa State University, Ames, IA 5001 3222, USA
    Med Vet Entomol 19:48-52. 2005
    ..S.A., England and southern Russia shared most of their mitochondrial diversities, but face flies from Kazakhstan were substantially dissimilar, suggesting highly restricted gene flow and a species complex within the Palearctic...
  12. ncbi Spatial diversity in mitochondrial cytochrome c oxidase in house flies
    M A Cummings
    Department of Entomology, Iowa State University, Ames, IA 50011 3222, USA
    Med Vet Entomol 19:53-9. 2005
    ..Probable colonization scenarios for house flies into the New World are discussed and it is concluded that house flies are a recent addition to the fauna of the Western Hemisphere...
  13. ncbi Temperature-dependence of metabolic rate in Glossina morsitans morsitans (Diptera, Glossinidae) does not vary with gender, age, feeding, pregnancy or acclimation
    John S Terblanche
    Spatial, Physiological and Conservation Ecology Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa
    J Insect Physiol 51:861-70. 2005
    ..These findings have implications for predicting the metabolic responses of tsetse flies to short-term temperature variation and may also have applications for modelling tsetse population dynamics as a function of temperature...
  14. pmc Macrogeographic population structure of the tsetse fly, Glossina pallidipes (Diptera: Glossinidae)
    J O Ouma
    Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
    Bull Entomol Res 95:437-47. 2005
    ..85 and averaged 0.42, and FST=0.51. High levels of genetic differentiation were characteristic, extending even to subpopulations separated by tens and hundreds of kilometres, and indicating low rates of gene flow...
  15. pmc The relative contributions of developmental plasticity and adult acclimation to physiological variation in the tsetse fly, Glossina pallidipes (Diptera, Glossinidae)
    John S Terblanche
    Spatial, Physiological and Conservation Ecology Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa
    J Exp Biol 209:1064-73. 2006
    ..pallidipes, and therefore that it is not only important to consider the form of plasticity but also the direction of the response and its significance from a life-history perspective...
  16. ncbi Discontinuous gas exchange in insects: a clarification of hypotheses and approaches
    Steven L Chown
    Spatial, Physiological, and Conservation Ecology Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
    Physiol Biochem Zool 79:333-43. 2006
    ....
  17. pmc Microgeographical breeding structure of the tsetse fly, Glossina pallidipes in south-western Kenya
    J O Ouma
    Tryanosomiasis Research Center, Kenya Agricultural Research Institute, Kikuyu, Kenya
    Med Vet Entomol 20:138-49. 2006
    ..Harmonic mean effective (= breeding) population sizes were 180 in Lambwe and 551 in Nguruman. The genetic data suggest that G. pallidipes in Lambwe and Nguruman have been endemic for long intervals...
  18. pmc Phenotypic plasticity and geographic variation in thermal tolerance and water loss of the tsetse Glossina pallidipes (Diptera: Glossinidae): implications for distribution modelling
    John S Terblanche
    Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
    Am J Trop Med Hyg 74:786-94. 2006
    ..Limited variation in CT(Max) supports bioclimatic models that suggest tsetse are likely to show range contraction with warming from climate change...
  19. ncbi Directional evolution of the slope of the metabolic rate-temperature relationship is correlated with climate
    John S Terblanche
    Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
    Physiol Biochem Zool 82:495-503. 2009
    ..These results therefore suggest evolutionary adaptation of MR-T reaction norms to cool climates (<22 degrees C) in tsetse and provide novel support for MCA within an insect species...