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

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 exist...

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Bibliographic Details
Published in:Evolutionary ecology 2011-11, Vol.25 (6), p.1269-1288
Main Authors: Bentz, Barbara J., Bracewell, Ryan R., Mock, Karen E., Pfrender, Michael E.
Format: Article
Language:English
Subjects:
Animal Ecology
Bark beetles
Biomedical and Life Sciences
Climate change
Dendroctonus ponderosae
Ecology
Evolution & development
Evolutionary Biology
Genetic diversity
Genotype & phenotype
Insects
Life Sciences
Original Paper
Pinus
Plant Sciences
Population biology
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Summary: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 F 2 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.
ISSN:0269-7653
1573-8477
DOI:10.1007/s10682-011-9474-x