Evolutionary Ecology

, Volume 25, Issue 6, pp 1269–1288

Genetic architecture and phenotypic plasticity of thermally-regulated traits in an eruptive species, Dendroctonus ponderosae

  • Barbara J. Bentz
  • Ryan R. Bracewell
  • Karen E. Mock
  • Michael E. Pfrender
Original Paper

DOI: 10.1007/s10682-011-9474-x

Cite this article as:
Bentz, B.J., Bracewell, R.R., Mock, K.E. et al. Evol Ecol (2011) 25: 1269. doi:10.1007/s10682-011-9474-x


Phenotypic plasticity in thermally-regulated traits enables close tracking of changing environmental conditions, and can thereby enhance the potential for rapid population increase, a hallmark of outbreak insect species. In a changing climate, exposure to conditions that exceed the capacity of existing phenotypic plasticity may occur. Combining information on genetic architecture and trait plasticity among populations that are distributed along a latitudinal cline can provide insight into how thermally-regulated traits evolve in divergent environments and the potential for adaptation. Dendroctonus ponderosae feed on Pinus species in diverse climatic regimes throughout western North America, and show eruptive population dynamics. We describe geographical patterns of plasticity in D. ponderosae development time and adult size by examining reaction norms of populations from multiple latitudes. The relative influence of additive and non-additive genetic effects on population differences in the two phenotypic traits at a single temperature is quantified using line-cross experiments and joint-scaling tests. We found significant genetic and phenotypic variation among D. ponderosae populations. Simple additive genetic variance was not the primary source of the observed variation, and dominance and epistasis contributed greatly to the genetic divergence of the two thermally-regulated traits. Hybrid breakdown was also observed in F2 hybrid crosses between northern and southern populations, further indication of substantial genetic differences among clinal populations and potential reproductive isolation within D. ponderosae. Although it is unclear what maintains variation in the life-history traits, observed plasticity in thermally-regulated traits that are directly linked to rapid numerical change may contribute to the outbreak nature of D. ponderosae, particularly in a changing climate.


Adult sizeBark beetleClimate changeDevelopment timeMountain pine beetleReaction norm

Copyright information

© Springer Science+Business Media B.V. (outside the USA) 2011

Authors and Affiliations

  • Barbara J. Bentz
    • 1
  • Ryan R. Bracewell
    • 2
  • Karen E. Mock
    • 3
  • Michael E. Pfrender
    • 4
    • 5
  1. 1.US Forest Service, Rocky Mountain Research StationLoganUSA
  2. 2.Department of Ecosystem and Conservation SciencesUniversity of MontanaMissoulaUSA
  3. 3.Wildland Resources DepartmentUtah State UniversityLoganUSA
  4. 4.Department of BiologyUtah State UniversityLoganUSA
  5. 5.Department of Biological Sciences109B Galvin Life Science CenterNotre DameUSA