Genetic Architecture of Differences in Fitness Traits among Geographically Separated Dendroctonus ponderosae populations
USDA Forest Service Proceedings
The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae) (MPB), is widely distributed across western North America spanning 25 degrees latitude and more than 2,500 m elevation. In a common garden experiment, Bentz and others (2001) observed that MPB populations from a southern location required significantly more time to develop than individuals from a population in the northern part of the range, although both populations exhibited univoltinism. Adults from the southern population were also significantly larger, even when reared in a common host and temperature. These results suggest that local selection plays a role in MPB adaptation to temperature, which can vary dramatically across the broad range of MPB. In a recent phylogeographic analyses of MPB, Mock and others (2007) found evidence of genetic structuring among populations that followed a broad isolation-by-distance pattern, confirming that genetic differences exist among geographically isolated populations. Little is known, however, about the underlying genetic architecture of important MPB life history traits, such as development time. To adequately forecast the effects of climate change on MPB population success and adaptability, a better understanding of the underlying environmental and genetic control of these traits, and variability across geographically separated populations, is needed. The main objective of our study was to examine the genetic architecture of differences among three geographically separated populations of MPB that differ in total development time and adult size. We used line cross experiments to analyze the relative influences of additive and nonadditive genetic effects on population differences in these traits.
Bentz B, Pfrender M, Bracewell R, Mock K (2007) Genetic architecture of differences in fitness traits among geographically separated Dendroctonus ponderosae populations. USDA Forest Service Proceedings RMRS-P-45.