Understanding polymorphism is a central problem in evolution and ecology, and alternative reproductive tactics (ARTs) provide compelling examples for studying the origin and maintenance of behavioral and morphological variation. Much attention has been given to examples where “parasitic” individuals exploit the reproductive investment of “bourgeois” individuals, but some ARTs are instead maintained by environmental heterogeneity, with alternative tactics exhibiting differential fitness in discontinuous reproductive niches. We use genomic, behavioral, karyological, and field observational data to demonstrate one such example in plethodontid salamanders. These ARTs (“search-ing” and “guarding” males) are associated with different reproductive niches and, unlike most other examples in amphibians, demonstrate substantial morphological differences and inflexibility within a reproductive season. Evidence suggests the existence of these ARTs within three putative species in the two-lined salamander (Eurycea bislineata) species complex, with other members of this clade fixed for one of the two tactics. We highlight directions for future research in this system, including the relationship between these ARTs and parental care.
Bibliographical noteFunding Information:
This research was funded in part by the American Philosophical Society?s Lewis and Clark Fund for Exploration and Field Research; the American Museum of Natural History?s Theodore Roosevelt Memorial Grant; the Society of Systematic Biologists?s Graduate Student Research Award; the University of Tennessee, Knoxville (UTK), Department of Ecology and Evolutionary Biology?s Departmental Research Funds; and the Lock Haven University Biological Sciences Department and Faculty Professional Development Committee. T.W.P.?s research was supported by a National Science Foundation Graduate Research Fellowship under grant DGE-1452154. We thank N. Bayona-V?squez, D. Beamer, J. Beane, S. Bolick, R. Bonett, M. Britz, C. Carter, E. Carter, J. Corush, J. Cunningham, A. Edwards, J. Fetterman, A. Funk, C. Gienger, T. Glenn, S. Graham, L. Hayter, H. Korotkin, W. Lattea, C. Miller, S. Nelson, T. Paulson, H. Rainey, N. Scobel, B. Stuart, S. Wesnak, and K. Young for help in the field and laboratory and for their advice in designing this research and preparing the manuscript. We especially thank D. Sever and R. Bruce for their enthusiasm for our research and helpful discussions in designing and interpreting our study. Finally, we thank HerpMapper (www.HerpMapper.org) and its citizen-scientist contributors, as their observations were instrumental in guiding this project. This research was covered under UTK Institutional Animal Care and Use Committee (IACUC) protocol 2471-0616, Lock Haven University IACUC protocol 01501, and Hartwick College IACUC protocol SKS-11. Collections and observations were permitted under the North Carolina Wildlife Resources Commission (17-SC00977), the Tennessee Wildlife Resources Agency (3840, 1213), the National Park Service (GRSM-2017-SCI-1198, GRSM-2018-SCI-1198), and the Cherokee and Nantahala National Forests.
© 2019 by The University of Chicago.
- Alternative reproductive tactics (ARTs)
- Eurycea wilderae
- Mate guarding
- Morph A