Seasonal life history adaptation in Drosophila melanogaster

Temporal changes in environmental selection pressures across seasonal time may result in seasonal oscillations of traits associated with high fitness that are favorable for reproduction and population expansion (summer) and those that are not and must be endured (winter). I have been collecting a long-term dataset measuring seasonal changes in fitness-related phenotypes, allele frequencies and environmental variables to provide an empirical investigation of seasonal life history changes driven by natural selection.

Adaptive role of innate immunity

The immune system sits at the crucial interface between an organism’s external and internal environment and this balance between self and other may be essential in adaptation to environmental heterogeneity. Drosophila melanogaster are saprophytic fungal specialists intimately associated with the surrounding microbial community and the innate immune response may be an important trait to respond to biotic variation along environmental gradients.  I am studying changes across space and time in innate immune survival, resistance and the underlying genetic basis of these changes.


I am interested in the genetic basis of adaptation in natural populations.  My research addresses physiological and behavioral responses of Drosophila melanogaster to abiotic and biotic environmental selection pressures.  I examine the genetic architecture underlying these complex phenotypes and how such traits are shaped by epistasis and pleiotropy. My specific research projects are detailed below.

Evolution of learning ability in natural populations 

Although learning is an important aspect of the biology of most organisms, its evolutionary significance is not well understood. It is assumed, although not thoroughly tested, that learning is adaptive in variable environments where fitness consequences of a behavior change across generations or within an individual’s lifespan. However, learning is costly in time, energy and risks associated with mistakes, therefore an unconditional genetically fixed response is hypothesized to evolve in predictable environments. I am studying how advertise shock and olfactory based learning changes across environmental gradients and I am testing the function of natural polymorphisms in candidate learning genes.

Genetic architecture underlying adaption in the wild

The genetic architecture underlying complex traits is generally assumed to be consistent across populations.  I am examining how genetic correlations change covariances of traits over space and across seasonal time. Additionally, I test the role of epistatis and pleiotropy in candidate genes of seasonally cycling SNPs identified through whole-genome resequencing. 

© 2016 by Emily L. Behrman. Proudly created with

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