Life in animal families creates opportunities for cooperation but is also fraught with conflict. Male and female parents must cooperate to create offspring and often must work together to successfully rear these young. However, there can be intense conflict between the sexes over aspects of mating and parental care. Similarly, interactions between parents and offspring can be viewed through the lenses of cooperation and conflict. Parents of many species provision their young and offspring may honestly communicate their need for parentally supplied resources. However, parents and offspring are usually not genetically identical to one another and this creates a conflict of interest, with offspring selected to demand more resources from their parents than is optimal for parents to supply. My research seeks to understand how this tension between cooperation and conflict affects the evolution of parental care. In particular, I study how social interactions among family members influence phenotypic variation, how these interactions generate natural selection, and how populations adapt and diversify in response to this selection. As a broadly trained evolutionary ecologist, my research integrates techniques and concepts from life-history theory, behavioral ecology, quantitative genetics, molecular ecology, and experimental evolution.
Using experimental evolution to study adaptations for family life
My current research uses experimental evolution to study how populations adapt to a change in the social environment that arises during parental care. This work involves experimental populations of the burying beetle, Nicrophorus vespilloides (left, photo courtesy of Tom Houslay), that are evolving under different mating systems.
Maternal-fetal conflict and coadaptation
My previous research tested whether conflict between mothers and embryos over the supply and demand of resources can influence evolutionary diversification. This work focused on a poeciliid fish, Heterandria formosa, in which females provision embryos via a placenta and must allocate their investment among several broods carried simultaneously. This creates conflict between mothers and embryos and between sibling embryos over maternal investment and can also lead to coadaptation of maternal and offspring traits.
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* undergraduate coauthor
22. Jarrett, B.J.M, E. Evans*, H. Haynes*, M Leaf*, D. Rebar, A. Duarte, M. Schrader, and R. Kilner. 2018 A sustained change in the supply of parental care causes adaptive evolution of offspring morphology. Nature Communications, in press.
21. Schrader, M., B. J. M. Jarrett, and R. M. Kilner. 2018 Parental care and sibling competition independently increase phenotypic variation among burying beetle siblings. Evolution, in press.
20. Schrader, M., B. J. M. Jarrett, D. Rebar, and R. M. Kilner. 2017 Adaptation to a novel family environment involves both apparent and cryptic phenotypic changes. Proceedings of the Royal Society of London B. 284: 20171295.
19. Jarrett, B. J. M., M. Schrader, D. Rebar and R. M. Kilner. 2017 Cooperative interactions within the family enhance the capacity for evolutionary change in body size. Nature Ecology and Evolution 1: 0178.
18. Palmer, W. J., A. Duarte, M. Schrader, J. P. Day, R. M. Kilner, and F. M. Jiggins. 2016. A gene associated with social immunity in the burying beetle, Nicrophorus vespilloides. Proceedings of the Royal Society of London B. 283: 20152733.
17. Schrader, M., R. M. Crosby*, A. Hesketh*, B. J. M. Jarrett, and R. M. Kilner. 2016. A limit on the extent to which increased egg size can compensate for a poor post-natal environment, revealed experimentally in the burying beetle, Nicrophorus vespilloides. Ecology and Evolution 6: 329-336.
16. Schrader, M., B. J. M. Jarrett, and R. M. Kilner. 2015. Using experimental evolution to study adaptations for life within the family. The American Naturalist 185: 610-619.
Recommended by the Faculty of 1000
15. Schrader, M., B. J. M. Jarrett, and R. M. Kilner. 2015. Parental care masks a density-dependent shift from cooperation to competition in burying beetle broods. Evolution 69: 1077-1084.
14. Schrader, M., R. C. Fuller, and J. Travis. 2013. Differences in offspring size predict the direction of isolation asymmetry between populations of a placental fish. Biology Letters 9: 20130327.
13. Apodaca, J. J., J. C. Trexler, N. Jue, M. Schrader, and J. Travis. 2013. Large-scale natural disturbance alters genetic population structure of the Sailfin Molly, Poecilia latipinna. The American Naturalist 181: 254-263.
12. Schrader, M. and J. Travis. 2012. Variation in offspring size with birth order in placental fish: a role for asymmetrical sibling competition? Evolution 66: 272-279.
11. Schrader, M., J. J. Apodaca, P. Macrae, and J. Travis. 2012. Population density does not influence male gonadal investment in the Least killifish, Heterandria formosa. Ecology and Evolution 2: 2935-2942.
10. Schrader, M. and J. Travis. 2012. Assessing the effects of population density and predation regime on the evolution of offspring size in populations of a placental fish. Ecology and Evolution 2: 1480-1490.
9. Schrader, M. and J. Travis. 2012. Embryonic IGF2 expression is not associated with offspring size among populations of a placental fish. PLoS ONE 7: e45463.
8. Schrader, M, J. Travis, and R.C. Fuller. 2011. Do density-driven mating system differences explain reproductive incompatibilities between populations of a placental fish? Molecular Ecology 20: 4140-4151.
7. Schrader, M. and J. Travis. 2009. Do embryos influence maternal investment? Evaluating maternal-fetal coadaptation and the potential for parent-offspring conflict in a placental fish. Evolution 63: 2805-2815.
6. Schrader, M. and J. Travis. 2008. Testing the viviparity-driven conflict hypothesis: parent-offspring conflict and the evolution of reproductive isolation in a poeciliid fish. The American Naturalist 172: 806-817.
5. Fuller, R. C., K. E. McGhee, and M. Schrader. 2007. Speciation in killifish and the role of salt tolerance. Journal of Evolutionary Biology 20: 1962-1975.
4. Schrader, M. and J. Travis. 2005. Population differences in pre- and post-fertilization offspring provisioning in the Least Killifish, Heterandria formosa. Copeia (3): 649-656.
3. Koenig, W. D., E. L. Walters, J. R. Walters, J. S. Kellam, K. G. Michalek, and M. S. Schrader. 2005. Seasonal body weight variation in five species of woodpeckers. The Condor 107: 810-822.
2. Schrader, M. S., E. L. Walters, and F. C. James, E. C. Greiner. 2003. Seasonal prevalence of a haematozoan parasite of the Red-bellied Woodpecker and its associations with host condition and overwinter survival. The Auk 120: 130-137.
1. Foster, G. W., J. M. Kinsella, E. L. Walters, M. S. Schrader, and D. J. Forrester. 2002. Parasitic helminthes of Red-bellied Woodpeckers (Melanerpes carolinus) from the Apalachicola National Forest in Florida. Journal of Parasitology 88: 1140.
Evolution (Bio 213)
Evolution is the best scientific explanation for the diversity of life and is the concept that unifies all of biology. In this course we discuss the pattern and process of evolution, the experimental and analytical methods that scientists use to study evolution, and the reasons why evolution is an important field of study. At the conclusion of the course, students will understand how the process of evolution unfolds, how scientists have deduced the mechanisms of evolution and reconstructed the history of life, and why evolution is the best scientific explanation for the diversity of life. Finally, I hope students come to recognize that the discovery of evolution is one of humanity’s greatest intellectual achievements.
Ornithology (Bio 201)
My aims for this course are to expose students to the diversity of birds, to teach students to identify birds in the field, and to examine how studies of birds have contributed to the broader fields of ecology, evolution, and behavior. By the end of this course, students will be able to identify local birds and understand how they are related to one another in a phylogenetic context. Students will also have a deeper awareness for the important role that studies of birds have played in the development of ecology and evolutionary biology.
Assistant Professor, Department of Biology, The University of the South
Post-doctoral Associate, Department of Zoology, University of Cambridge
Advisor: Rebecca Kilner
Post-doctoral Associate, Department of Animal Biology, University of Illinois
Advisors: Rebecca Fuller and Carla Cáceres
PhD, Department of Biological Science, Florida State University, 2009
Advisor: Joseph Travis.
M.S., Department of Biological Science, Florida State University, 2003
Advisor: Frances James
B.S., Zoology, University of Florida, 1997