Sociobiology of Caviomorph Rodents
Highlights potential parallels and differences with other animal models
Sociobiology of Caviomorph Rodents
Luis A. Ebensperger1 & Loren D. Hayes2
1 Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
2 Department of Biology, Geology, and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN, USA
I.1 Social behavior of caviomorph rodents and book aims
Social behavior involves the actions directed toward, or in response to conspecifics and the fitness consequences for all individuals involved (Wersinger 2009; Székely et al. 2011). Given that social interactions are diverse in nature and extent, social behavior is similarly diverse. Thus, social behavior encompasses a variety of agonistic (including aggressive) behaviors that result in the establishment of dominance hierarchies and territoriality, but also a similarly diverse array of affiliative interactions. Affiliative interactions takes place in different contexts, including courtship and other sexual interactions that result in mating systems , parent-offspring interactions that result in parental care patterns, or the relatively permanent association of adult conspecifics that result in sociality (or group-living) and different forms of cooperation.
In the late 1990s and early 2000s, some researchers began to argue that generalizations about rodent social behavior were premature due to the lack of information coming from the caviomorph or New World hystricognath rodents, a socially diverse group of South American rodents (Ebensperger 1998; Tang-Martínez 2003). We propose that a greater focus on caviomorph rodents as subject models of social behavior would contribute greatly to collaborative and integrative research on this area. Caviomorph rodents exhibit a diverse range of social behaviors and life history attributes, and are found in a wide range of habitats. Caviomorphs span from solitary living (Adler 2011) to highly social (Herrera et al. 2011), and live in kin-biased (Lacey & Wieczorek 2004) or non-kin biased (Quirici et al. 2011) groups. Some species provide communal care to offspring (Ebensperger et al. 2007) while others attempt to avoid contact with non-descendant offspring held in communal crèches (Taber & Mcdonald 1992; Campos et al. 2001). Mating systems are equally diverse, with some species exhibiting monogamy and territoriality , while others exhibit polygyny , or promiscuity (Adrian & Sachser 2011). In terms of life history, caviomorph rodents exhibit a mixture of "fast" and "slow" traits; many have long gestation periods and produce small litters of precocial offspring , yet reach sexual maturity at a young age and exhibit low survival (Kraus et al. 2005). High mortality rates effectively make some species semelparous (Ebensperger et al. 2013). Finally, caviomorph rodents are ecologically diverse, occurring in habitats such as high and low altitude shrublands, tropical and temperate forests, and coastal areas. Habitats range from arboreal to semiaquatic to subterranean. Numerous species have wide geographical ranges, increasing the potential for social and life history flexibility.
Historically, the caviomorph rodents have offered diverse opportunities to studies focused primarily on functional or evolutionary explanations of social behavior. However, caviomorphs are also emerging as good model organisms for integrative research (Colonnello et al. 2011; Ardiles et al. 2013). Researchers have started to make in-roads into the neural mechanisms underlying social variation (e.g. Seidel et al. 2011; Uekita & Okanoya 2011), facilitating comparative analyses that cast mechanism in an evolutionary context (Beery et al. 2008). In some species, we are beginning to understand the neuroendocrine (Ebensperger et al. 2011, 2013) and immunological (Ebensperger et al.