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D. Nicholas McLetchie


Ph.D. Ecology, Univ. of Tennessee, Knoxville, 1993
BS in Botany, Howard University, 1984


Please see 'Lab website' link (on left side and below contact phone number ) for more recent and complete information.


There are few greater obstacles to sexual reproduction than the rarity or absence of one sex. Limited or no sexual reproduction can result in a species inability to adapt to a changing environment, leading to population declines and eventually species extinction. Yet among plants, specifically bryophytes, rarity or absence of one sex occur frequently. An illustration of this pattern occurs in the liverwort Acrobolbus ciliatus Mitt. which is found as males in Japan and females in the Appalachian mountains in the USA . Although intriguing, the underlying causes of these patterns have infrequently been investigated. My research program focuses on elucidating the factors resulting in an entire species or population being dominated by one sex. Such factors include variation in offspring sex ratios and sex differences in clonal expansion that are a function of differential growth, asexual reproduction, colonization and survival as well as sex differences in sex expression.

To study the causes and consequences of sex ratio variation we use an unusually broad array of techniques, including molecular-genetic analysis, physiological methods, greenhouse and growth chamber experiments, field experiments and monitoring, and mathematical modeling. We consider the structure and dynamics of individuals, local clusters of individuals (patches), and patch assemblages, and interactions among them and the environment.

Check out "Plant Reproduction with the Nicholas McLetchie Lab" video here!

Check out "Plant Reproduction with the McLetchie Lab" podcast here!

Selected Publications:

Publications since 2009 SEE 'LAB WEBSITE' LINK (upper right in the 'CONNECT' box) FOR MORE RECENT INFORMATION

  1. Silva-e-Costa, J.d.C.; Luizi-Ponzo, A.P.; McLetchie, D.N. 2022 Sex Differences in Desiccation Tolerance Varies by Colony in the Mesic Liverwort Plagiochila porelloides. Plants, 11, 478. 10.3390/plants11040478
  2. Marks, R. A., Smith J. J., VanBuren R. Mcletchie, D. N., 2021 Expression dynamics of dehydration tolerance in the tropical plant Marchantia inflexa. The Plant Journal 105, 209–222
  3. Marks, R. A., Farrant J. M. Mcletchie, D. N., VanBuren R. 2021, Unexplored dimensions of variability in vegetative desiccation tolerance. American Journal of Botany. 108 346-358
  4. Lim, G., Liu, H., Yu, K., Liu, R., Shine, M. B., Fernandez, J., Burch-Smith, T., Mobley, J. K., McLetchie, N., Kachroo, A., Kachroo, P. 2020. The plant cuticle regulates apoplastic transport of salicylic acid during systemic acquired resistance. Science Advances DOI: 10.1126/sciadv.aaz0478
  5. Marks, R. A., Smith J. J., Cronk Q., Grassa C.J., McLetchie DN, (2019) Genome of the tropical plant Marchantia inflexa: implications for sex chromosome evolution and dehydration tolerance. Scientific Reports
  6. Castetter R C., McLetchie D. N, Eppley S. M., Stark L. R., (In Press) Sex Ratio and Sex Expression in an Urban Population of the Silver Moss, Bryum argenteum . Journal of Bryology.
  7. McLetchie DN, Stark LR (In Press) Rate of drying influences tolerance of low water contents in the moss Funaria hygrometrica (Funariaceae) The Bryologist.
  8. Raudenbush Z., Greenwood J L., McLetchie D. N., Eppley S. M., Keeley S J. Castetter R C., & Stark L. R., 2018 Divergence in life history and developmental traits in Bryum argenteum genotypes between golf course putting greens and native habitats Weed Science. 66: 642–650 doi: 10.1017/wsc.2018.37
  9. Marks, R. A., Smith, J. J., Cronk, Q., & McLetchie D. N. 2018. Variation in the bacteriome of the tropical liverwort, Marchantia inflexa, between the sexes and across habitats. Symbiosis, 75 93-101. (Online Nov3 2017)
  10. McLetchie D. N., García-Ramos G. 2017. A predictive relationship between population and genetic sex ratios in clonal species. Acta Oecologica. 80: 18-23.
  11. Stieha C., G García-Ramos, D.N. McLetchie, P. Crowley. 2017. Maintenance of the Sexes and Persistence of a Clonal Organism in Spatially Complex Metapopulations.  Evolutionary Ecology DOI 10.1007/s10682-016-9841-8
  12. Moore J.D., L. Kollar D.N. McLetchie (2016) Does selection for gamete dispersal and capture lead to a sex difference in clump water-holding capacity? American Journal of Botany doi:10.3732/ajb.1600096
  13. Rose M., J. Burton D.N. McLetchie. 2016. Sex differences and plasticity in dehydration tolerance: insight from a tropical liverwort. Annals of Botany doi: 10.1093/aob/mcw102
  14. Stieha C., G García-Ramos, D.N. McLetchie, P. Crowley. 2016. Maintenance of the Sexes and Persistence of a Clonal Organism in Spatially Complex Metapopulations.  Evolutionary Ecology DOI 10.1007/s10682-016-9841-8
  15. Stark L. R, D. N. McLetchie, S. M. Eppley and J. L. Greenwood. 2016. Moss Antheridia are Desiccation Tolerant: Rehydration Dynamics Influence Sperm Release in Bryum argenteum (Bryaceae) American Journal of Botany doi:10.3732/ajb.1600026
  16. Stieha C., A. Middleton, J. Stieha; S. Trott, D. N. McLetchie. 2014 The dispersal process of asexual propagules and the contribution to population persistence in Marchantia (Marchantiaceae) American Journal of Botany 101:348-356. doi:10.3732/ajb.1300339
  17. Brzyski, J. R., W. Taylor, D. N. McLetchie. 2014. Reproductive allocation between the sexes, across natural and novel habitats, and its impact on genetic diversity. Evolutionary Ecology 28: 247-261. 10.1007/s10682-013-9672-9
  18. Brzyski, J., K. Adams, C. Walter, K. H. Gale, D. N. McLetchie. 2012 Characterization of 12 polymorphic microsatellite markers in the liverwort Marchantia inflexa (Marchantiaceae) American Journal of Botany (vol. 99 no. 11 e440-e442).
  19. Stark L. R., J C Brinda, D. N. McLetchie, M J Oliver. 2012 Extended periods of hydration do not elicit dehardening to desiccation tolerance in regeneration trials of the moss Syntrichia caninervis. International Journal of Plant Sciences 173 333-343. 10.1086/663970
  20. Reynolds, L. A., and D N. McLetchie. 2011 Short distance between extreme microhabitats do not result in ecotypes in Syntrichia caninervis, Journal of Bryology 33: 148-153 10.1179/1743282011Y.0000000004
  21. Benassi, M. L., L. R. Stark, J. C. Brinda, D. N. McLetchie, M. Bonine, and B.D. Mishler. 2011 Plant size, sex expression, and sexual reproduction along an elevation gradient in a desert moss. The Bryologist 114:277-288 10.1639/0007-2745-114.2.277
  22. Horsley K., L. R. Stark, and D. N. McLetchie. 2011 Does the silver moss Bryum argenteum exhibit sex-specific patterns in vegetative growth rate, asexual fitness, or prezygotic reproductive investment? Annals of Botany 107: 897-907 doi: 10.1093/aob/mcr027
  23. Stark L. R., J C Brinda, D. N. McLetchie 2011 Effects of increased summer precipitation and N deposition on Mojave Desert populations of the biological crust moss Syntrichia caninervis, Journal of Arid Environments 75: 457-463  doi:10.1016/j.jaridenv.2010.12.015
  24. Stark, L. R., D. N. McLetchie, and S. M. Eppley.. 2010 Sex ratios and the shy male hypothesis in the moss Bryum argenteum (Bryaceae) The Bryologist. 113: 788-797 (
  25. Groen, K. E., Stieha, C., Crowley, P. H., and McLetchie, D. N. 2010 Sex-specific plant responses to light intensity and canopy openness: implications for spatial segregation of the sexes. Oecologia 162: 561-570 doi:10.1007/s00442-009-1473-z
  26. Groen, K. E., Stieha, C., Crowley, P. H., and McLetchie, D. N. 2010 Sex-specific plant responses to two light levels in the liverwort Marchantia inflexa (Marchantiaceae). The Bryologist. 113: 81-89.
  27. Cole, C., Stark, L. R., Bonine M., and McLetchie, D. N. 2010. Transplant survivorship of bryophyte soil crusts in the Mojave Desert. Restoration Ecology 18: 198-205. doi:10.1111/j.1526-100X.2008.00445.x.
  28. Stark, L. R, Brinda, J. and McLetchie, D. N. 2009 An experimental demonstration of the cost of sex and a potential resource limitation on reproduction in the moss Pterygoneurum (Pottiaceae). American Journal of Botany 96: 1-11. doi:10.3732/ajb.0900084
  29. Stark, L. R, McLetchie D. N. and Roberts S. 2009. Gender differences and a new adult eukaryotic record for upper thermal tolerance in the desert moss Syntrichia caninervis Journal of Thermal Biology 34: 131-137. doi:10.1016/j.jtherbio.2008.12.001



Book Chapter

Stark, L. R., D. N. McLetchie, S. D. Smith and M. J. Oliver. 2011. Responses of a biological crust moss to increased monsoon precipitation and N deposition in the Mojave Desert. pp. 149-168 in Tuba Z, Slack N, and Stark L. (eds), Bryophyte Ecology and Climate Change. Cambridge University Press. Cambridge. 


Education Beyond the Classroom

Stieha, C. and McLetchie, D.N. Degradation of a Tropical Stream.  2012. EcoEd Digital Library.