Presentation Detail

Evolutionary Ecology

Behrman, Emily [1], O'Brien, Katherine [1], Watson, Samuel S [2], Schmidt, Paul [1].

Strong seasonal selection results in rapid life history changes in Drosophila.

Variation in spatial and temporal selection pressures can maintain genetic diversity in natural populations. The gradients in environmental parameters that shape latitudinal clines are in many ways parallel to seasonal variation in temperate environments. Thus, there is the potential that multivoltine organisms in temperate environments undergo strong seasonal selection that results in rapid adaptation. Here, the age structure and life history trade-offs of wild populations of Drosophila melanogaster are examined throughout the growing season from spring to late fall over repeated years. Additionally, patterns of variation in life history traits are partitioned into effects associated with seasonal change in environmental quality (e.g.,phenotypic plasticity) and temporal change in genetic composition (e.g., response to environmentally mediated selection). When compared to D. simulans,the results show distinct trajectories by species; D. melanogaster appears to be a resident population that responds rapidly to environmental selection pressures throughout the growing season while D. simlulans is a transient population that cannot respond to short-scale changes and recolonizes annually. The data demonstrate that wild Drosophila routinely survive to an age where senescence should be evident if not pronounced; age-specific performance is therefore predicted to have significant effects on organismal fitness, but selection on age-specific parameters would covary with observed temporal changes in the underlying age structure of the population. Furthermore, the observed variance in age structure and life histories across seasonal time is predicted to have a significant impact on the evolutionary dynamics of life histories and associated traits in natural populations.

1 - University of Pennsylvania, Biology, 216 Leidy Laboratory, 3740 Hamilton Walk, Philadelphia, PA, 19104, USA
2 - Massachusetts Institute of Technology, Mathematics, Building 2 Room 489 , 77 Massachusetts Avenue , Cambridge, MA, 02139

Keywords:
Adaptation
Life history
seasonality
Rapid adaptation
climate
Drosophila melanogaster.

Presentation Type: Regular Oral Presentation
Session: 6
Location: Alpine C/Snowbird Center
Date: Saturday, June 22nd, 2013
Time: 8:30 AM
Number: 6001
Abstract ID:14
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation,Student Travel Awards from the ASN