CHAPTER FIVE Variation, plasticity, and alternative mating tactics: Revisiting what we know about the socially monogamous prairie vole Jesus E. Madrida, Karen J. Parkerb, Alexander G. Ophira,∗ aDepartment of Psychology, Cornell University, Ithaca, NY, United States bDepartment of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States ∗ Corresponding author: e-mail address:
[email protected] Contents 1. Introduction 203 2. Mating systems 205 2.1 Mating system evolution: Social, spatial, and ecological demands 205 2.2 Variation and flexibility in mating systems 207 3. Comparing mating systems among vole species 208 3.1 Reproductive ecology of prairie voles and meadow voles 209 3.2 Studying monogamous behaviors in laboratory settings 210 3.3 Variation in monogamous behaviors in field settings 212 4. Alternative mating tactics in prairie voles 215 4.1 A tale of two tactics: Residents and wanderers 215 4.2 Neurobiological differences underlying laboratory measures of monogamy 219 4.3 Neurobiological differences underlying field-based measures of monogamy 223 5. Mating tactics respond to social, ecological, and spatial contexts 226 6. Conclusions 230 References 231 1. Introduction Species’ mating systems are often characterized as either monogamous or non-monogamous, and this distinction has enabled comparative investi- gations that have advanced our understanding of the neurobiological basis of Advances in the Study of Behavior, Volume 52 # 2020 Elsevier Inc. 203 ISSN 0065-3454 All rights reserved. https://doi.org/10.1016/bs.asb.2020.02.001 204 Jesus E. Madrid et al. specific reproductive behaviors like pair bonding and parental behavior (Bester-Meredith, Young, & Marler, 1999; Goodson, 2013; Goodson & Bass, 2001; Walum & Young, 2018; Young et al., 2019; Young, Gobrogge, Liu, & Wang, 2011; Young & Wang, 2004).