Meeting Abstract
29-7 Friday, Jan. 4 15:00 – 15:15 The Effect of Aerobic Performance on High-Elevation Deer Mouse Survival SENNER, N.R.*; SASSER, K.T.; WOLF, C.J.; VELOTTA, J.P.; SCHWEIZER, R.M.; STAGER, M; CHEVIRON, Z.A.; University of South Carolina; University of Montana; University of Montana; University of Montana; University of Montana; University of Montana; University of Montana nathan.senner@gmail.com
Physiological traits are often hypothesized to directly influence fitness. Relatively few studies, however, have actually been able to quantify this link, nor investigate how the relationship may vary across environmental gradients. One such physiological trait frequently thought to be correlated with fitness is aerobic performance: numerous studies have found evidence that enhanced aerobic performance has evolved at high elevations where the partial pressure of oxygen is significantly reduced. What remains unclear, though, is how strongly and regularly selection is acting on populations and whether the strength of that selection varies with elevation or levels of connectivity among populations. To explore the link between physiology, gene flow, fitness, and elevation, we quantified how an individual’s aerobic performance affected the survival of deer mice, Peromyscus maniculatus, along two transects spanning an elevational gradient in the Colorado Rockies from 2200 – 4300 m. We found that the strength of selection on aerobic traits was strong at mid-elevations — from 2200 – 3000 m — but weak at higher elevations. Furthermore, higher elevation populations exhibit reduced phenotypic variation, as well as reduced genetic variation for genes under selection. This suggests a history of strong selection at high elevations, but also that high-elevation populations may now be locally adapted. Thus, although extreme environments are thought to regularly push extremophiles close to the edge of their physiological capabilities, consistent directional selection may enable populations to become locally adapted to even the harshest conditions.
