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Department of Entomology

Department of Entomology
123 W. Waters Hall
1603 Old Claflin Place
Kansas State University
Manhattan KS 66506-4004

785-532-6232 fax

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Ragland, Gregory

Greg Ragland

Assistant Professor

Department of Entomology
Kansas State University
123 W. Waters Hall
Manhattan, KS  66506
Phone(s): 785-532-6139
E-mail: gragland@ksu.edu

Lab Website


BA (Marine Science) - University of San Diego

MS (Biology) - Washington State University

PhD (Biology) - University of North Carolina at Chapel Hill, 2007


Research Emphasis:

Variable environments make life difficult. Seasonality is a prime example and a pervasive element of nearly every terrestrial and many aquatic environments. Animals, plants, bacteria, and just about any other form of life face long, and often extreme seasonal hardships. Resources and mates are often available for only a short time, while harsh conditions can persist for much longer. Evolved strategies for dealing with environmental variability are highly diverse, incorporating elements of life cycle timing, phenotypic plasticity, and general stress resistance. Environmental change, therefore, can be a powerful driver of population divergence and speciation. My goal is to understand both the selective factors giving rise to this diversity and the physiological and genetic underpinnings of adaptations to variable environments. Insects provide the ideal model system, exhibiting an extraordinary diversity of strategies for dealing with rapidly changing environmental challenges.

Many of the questions that I address center on insect diapause. Like many types of organisms, insects have evolved strategies to avoid environmental hardships such as harsh, cold winters at higher latitudes or altitudes. Diapause is a dormant, metabolically depressed state that may be obligate or environmentally cued. My research currently focuses on three major aspects of response to environmental change within the context of dormant life cycles:

  1. Genomic architecture of seasonal adaptation during speciation
  2. Functional genomic approaches to link physiological variation with adaptive changes in diapause regulation
  3. Adaptation across the life cycle, shaped by the interaction between seasonal climate and phenology, or life history timing

In addition to rapid changes in climate, we are also experiencing profound changes in the biotic environment through introductions and invasions. I am also interested in adaptation to novel nutritional environments during host race formation in the wild and in experimental population.


Recent publications: 

  • Reidenbach, K, D Neafsey, C Costantini, N Sagnon, F Simard, G Ragland, S Egan, J Feder, M Muskavitch, and N Besansky. 2012. Patterns of genomic differentiation between ecologically differentiated M and S forms of Anopheles gambiae in West and Central Africa. Genome Biology and Evolution 4: 1202-1212.[pdf]

  • Ragland, GJ, S Goudarzi, S Sim, JL Feder, and DA Hahn. 2012. Environmental interactions during host race formation: host fruit environment moderates a seasonal shift in phenology in host races of Rhagoletis pomonella. Functional Ecology 26: 921-931. [pdf]

  • Teets, NM, JT Peyton, GJ Ragland, H Colinet, D Renault, DA Hahn, and DL Denlinger. 2012. Combined transcriptomic and metabolomic approach uncovers molecular mechanisms of cold tolerance in a temperate flesh fly. Physiological Genomics 44: 764-777. [pdf]  *Faculty of 1000 recommended read*

  • GJ Ragland, SP Egan, JL Feder, SH Berlocher, and DA Hahn. 2011. Developmental trajectories of gene expression reveal candidates for diapause termination, a key life history transition in the apple maggot fly, Rhagoletis pomonella. Journal of Experimental Biology 214: 3948-3960. [pdf]  *Featured in InsideJEB*

  • GJ Ragland, DL Denlinger, and DA Hahn. 2010. Mechanisms of suspended animation are revealed by transcript profiling of diapause in the flesh fly. Proc. Natl. Acad. Sci. 107: 14909-14. [pdf]

  • Schwarz, D, HM Robertson, JL Feder, K Varala, ME Hudson, GJ Ragland, DA Hahn and SH Berlocher. 2009. Sympatric ecological speciation meets pyrosequencing: sampling the transcriptome of the apple maggot Rhagoletis pomonella. BMC Genomics 10: 633. [pdf]

  • Hahn, DA, GJ Ragland, DD Shoemaker and DL Denlinger. 2009. Gene discovery using massively parallel pyrosequencing to develop ESTs for the flesh fly Sarcophaga crassipalpis. BMC Genomics 10: 234.[pdf]

  • Ragland, GJ, J Fuller, JL Feder, and DA Hahn. 2009. Biphasic metabolic rate trajectory of pupal diapause termination and post-diapause development in a tephritid fly. Journal of Insect physiology 55: 344-350[pdf]

  • Kingsolver, JG, GJ Ragland, and SE Diamond. 2009. Evolution in a constant environment: thermal fluctuations and thermal sensitivity of laboratory and field populations of Manduca sexta. Evolution 63: 537-541. [pdf]

  • Ragland, GJ and JG Kingsolver. 2008. Evolution of thermotolerance in seasonal environments: the effects of annual temperature variation and life history timing in Wyeomyia smithii. Evolution 62: 1345-1357.[pdf]  *Faculty of 1000 recommended read*

  • Ragland, GJ and JG Kingsolver. 2008. The effect of fluctuating temperatures on ectotherm life history traits: comparisons among geographic populations of Wyeomyia smithii. Evolutionary Ecology Research 10: 29-44. [pdf]

  • Ragland, GJ and JG Kingsolver. 2007. Influence of seasonal timing on thermal ecology and thermal reaction norm evolution in Wyeomyia smithii. Journal of Evolutionary Biology 20: 2144-2153. [pdf]

  • Kingsolver, JG, KR Massie, GJ Ragland, and MH Smith. 2007. Rapid population divergence in thermal reaction norms for an invading species: breaking the temperature-size rule. Journal of Evolutionary Biology 20: 892-900. [pdf]

  • Kingsolver, JG, KR Massie, JG Shlichta, MH Smith, Ragland, GJ, and R Gomulkiewicz. 2007. Relating environmental variation to selection on reaction norms: an experimental test. American Naturalist 169: 163 - 174. [pdf]

  • Kingsolver, JG, JG Shlichta, GJ Ragland, and KR Massie. 2006. Thermal reaction norms for caterpillar growth depend on diet. Evolutionary Ecology Research 8: 703-715. [pdf]

  • Ragland, GJ and PA Carter. 2004. Genetic covariance structure of growth in the salamander Ambystoma macrodactylum. Heredity 92: 569-578. [pdf]

  • Kingsolver, JG, GJ Ragland, and JG Shlichta. 2004. Quantitative genetics of continuous reaction norms: thermal sensitivity of caterpillar growth rates. Evolution 58: 1521-1529. [pdf]

  • Kingsolver, JG, R Izem, and GJ Ragland. 2004. Plasticity of Size and Growth in Fluctuating Thermal Environments: Comparing Reaction Norms and Performance Curves. Integrative and Comparative Biology 44: 450-460. [pdf]