Susan Bertram
Maintenance of Variation in Sexually Selected Traits
Dr. Bertram's research utilizes a myriad of laboratory and field-based techniques to investigate the major inconsistency between theory and data in explaining the maintenance of variation in sexually selected traits. Theoretically, all fitness-conferring traits should display minimal amounts of genetic variation. This theory is based on the notion that fitness is influenced by directional selection and therefore a single best phenotype should predominate. Provided this theory is accurate, sexually selected traits should strongly influence fitness and therefore display minimal amounts of heritable variation. However, sexually selected traits exhibit even higher levels of heritable variation than other fitness-conferring traits in similar taxa. Her research addresses the causal question of how variation is maintained in sexually selected traits, and focuses on the field cricket as the model organism. Further details about her research can be found at the Bertram Lab Web Site.
Selected Publications
Gorelick, R., S.M. Bertram, P. Killeen., and J.H. Fewell. 2004. Quantifying division of labour and other uses of normalized mutual entropy in biology. American Naturalist In Press .
Gorelick, R. and Bertram, S.M. 2003. Maintaining heritable variation via sex-limited temporally fluctuating selection: a phenotypic model accommodating non-Mendelian epigenetic effects. Theory in Biosciences 122: 321-338.
Bertram, S.M., R. Gorelick, and J.H. Fewell. 2003. Colony response to graded resource changes: an analytical model of the influence of genotype, environment, and inheritance pattern. Journal of Theoretical Population Biology : 64:151-162
Bertram, S.M. 2002. Temporally fluctuating selection of sex-limited signaling traits in the Texas Field cricket, Gryllus texensis. Evolution 56: 1831-1839
Fewell, J. H. and S.M. Bertram. 2002. Genetic variation in worker task performance by African and European honey bees. Behavioral Ecology and Sociobiology 52: 318-325
Bertram, S.M. and R. Bellani . 2002. The influence of photoperiod on temporal mate signaling patterns. Journal of Insect Behavior 15: 607-615
Bertram, S.M. 2002. The influence of rearing and monitoring environment on temporal mate signaling patterns in the field cricket, Gryllus texensis. Journal of Insect Behavior 15: 127-137
Bertram, S.M. 2000. The influence of age and size on temporal mate signaling behaviour. Animal Behaviour 60:333-339
Fewell, J.H. and S.M. Bertram. 1999. Division of labor in a dynamic environment: response by honeybees ( Apis mellifera ) to graded changes in colony pollen stores. Behavioral Ecology and Sociobiology 46:171-179
Bertram, S.M., and L. Johnson. 1998. An electronic technique for monitoring the temporal aspects of acoustic signals of captive organisms. BioAcoustics 9:107-118