Publications

  • S. Freedberg, C. Urban, and B. M. Cunniff. 2021. Dispersal reduces interspecific competitiveness by spreading locally harmful traits. Journal of Evolutionary Biology, 34:1477-1487.
  • S. Freedberg. 2020. Long-Term Nest-Site Fidelity in the Mississippi Map Turtle, Graptemys pseudogeographica kohnii. Chelonian Conservation and Biology, 19.2:305-308.
  • E. M. Butka and S. Freedberg. 2019. Population structure leads to male-biased sex ratios under environmental sex determination. Evolution, 73:99-110.
  • S. Rood and S. Freedberg. 2016. Intragenomic conflict produces sex-ratio dynamics that favor maternal sex-ratio distorters. Ecology and Evolution, 6:8085-8093.
  • C. J. Reinertsen, S. M. Mitchell, K. H. Bao, K. M. Halvorson, M. J. Pappas, and S. Freedberg. 2016. Genetic variation and gene flow at the range edge of two softshell turtles. Journal of Herpetology, 50:357-365.
  • S. M. Mitchell, L. K. Muehlbauer, and S. Freedberg. 2016. Nuclear introgression without mitochondrial introgression in two turtle species exhibiting sex‐specific trophic differentiation. Ecology and Evolution, 6:3280-3288.
  • J. L. Riley, S. Freedberg, and J. D. Litzgus. 2015. Incubation temperature in the wild influences hatchling phenotype of two freshwater turtle species. Evolutionary Ecology Research, 16:397-416.
  • A. E. Johnson and S. Freedberg. 2014. Variable facial plumage in juvenile Cliff Swallows: A potential offspring recognition cue? The Auk, 131:121-128.
  • S. Freedberg and S. J. Debenport. 2014. Weakened purifying selection leads to elevated mutation load under environmental sex determination. Journal of Evolutionary Biology, 27:643-65.
  • R. Hofmeister, M. Welk, and S. Freedberg. 2013. Elevated levels of δ15N in riverine Painted Turtles (Chrysemys picta): trophic enrichment or anthropogenic input? Canadian Journal of Zoology, 91: 899-905.
  • M. J. Pappas, J. D. Congdon, B. J. Brecke, and S. Freedberg. 2013. Orientation of freshwater hatchling Blanding’s (Emydoidea blandingii) and snapping turtles (Chelydra serpentina) dispersing from experimental nests in agricultural fields. Herpetological Conservation and Biology, 8:385-399.
  • S. Freedberg and E. M. Myers. 2012. Different rates of mitochondrial and nuclear DNA introgression in a turtle lacking sex chromosomes. Biological Journal of the Linnean Society. 106:405-417.
  • S. Freedberg, C. Lee, and M. Pappas. 2011. Agricultural practices alter sex ratios in a reptile with environmental sex determination. Biological Conservation, 144:1159–1166.
  • J. S. Doody, S. Freedberg, and J. S. Keogh. 2009. Communal egg-laying in reptiles and amphibians: evolutionary patterns and hypotheses. Quarterly Review of Biology. 84:229-252.
  • S. Freedberg, T. J. Greives, M. A. Ewert, G. E. Demas, N. Beecher, and C. E. Nelson. 2008. Incubation environment affects immune system development in a turtle with environmental sex determination. Journal of Herpetology, 42:536-541.
  • S. Freedberg and D. R. Taylor. 2007. Sex ratio variance and the maintenance of environmental sex determination. Journal of Evolutionary Biology, 20:213-220.
  • S. Freedberg and D. R. Bowne. 2006. Monitoring juveniles across years reveals non-Fisherian sex ratios in a reptile with environmental sex determination. Evolutionary Ecology Research, 8:1499–1510.
  • S. Freedberg, R. M. Bowden, M. A. Ewert, D. R. Sengelaub and C. E. Nelson. 2006. Long-term sex reversal by oestradiol in amniotes with heteromorphic sex chromosomes. Biology Letters, 2:378-381.
  • S. Freedberg, C. E. Nelson, and M. A. Ewert. 2006. Estradiol-17β induces lasting sex reversal at male-producing temperatures in Kinosternid turtles. Journal of Herpetology, 40:95-98.
  • S. Freedberg, M. A. Ewert, B. J. Ridenhour, M. Neiman, and C. E. Nelson. 2005. Nesting fidelity and molecular evidence for natal homing in the freshwater turtle, Graptemys kohnii. Proceedings of the Royal Society of London: Biological Sciences, 272:345-350.
  • S. Freedberg, A. Stumpf, M. A. Ewert, and C. E. Nelson. 2004. Developmental environment has long lasting effects on behavioral performance in two turtles with environmental sex determination. Evolutionary Ecology Research, 6:739-747.
  • S. Freedberg and M. J. Wade. 2004. Male combat favours female-biased sex ratios under environmental sex determination. Animal Behaviour, 67:177-181.
  • S. Freedberg. 2002. Whole brood mortality increases the opportunity for female-biased sex ratios under local mate competition. Evolutionary Ecology Research, 4:421-429.
  • R. M. Bowden, M. A. Ewert, S. Freedberg, and C. E. Nelson. 2002. Maternally derived yolk hormones vary in follicles of the painted turtle, Chrysemys picta. Journal of Experimental Zoology, 293:67-72.
  • S. Freedberg, M. A. Ewert, and C. E. Nelson. 2001. Environmental effects on fitness and consequences for sex allocation in a reptile with environmental sex determination. Evolutionary Ecology Research, 3:953-967.
  • S. Freedberg and M. J. Wade. 2001. Cultural inheritance as a mechanism for population sex-ratio bias in reptiles. Evolution, 55:1049-1055.
  • M. Nickels, C. Nelson, D. Karpa-Wilson, S. Freedberg, and N. Murphy. 2001. Molecular sequences and primate evolution: An amino acid example. in Tested Studies for Laboratory Teaching. 22:339-344. Association for Biology Laboratory Education.
  • C. Nelson, M. Nickels, D. Karpa-Wilson, S. Freedberg, and N. Murphy. 2001. Human origins: Hominoid skull comparisons. in Tested Studies for Laboratory Teaching. 22:347-350. Association for Biology Laboratory Education.

  • Turtles in the bottom row were incubated at 25°C, leaving them with poor coordination and long righting times. Turtles in the middle row were incubated at 30°C and right quickly. Because female turtles must leave the water to build nests every year, they require more agility than males. Sex determination has evolved to produce females at the warm temperatures that benefit them most (Freedberg et al. 2001, Freedberg et al. 2004).