A preference to bond? Male prairie voles form pair bonds even in the presence of multiple receptive females

Abstract

Pair bonds are the cornerstone of a monogamous relationship. When individuals of the same species engage in monogamy and promiscuity (i.e. alternative reproductive tactics) it can be difficult to determine which tactic confers greater fitness, as measures of fitness can be difficult to ascertain. However, in these circumstances, whether animals preferentially establish pair bonds can reveal decisions that presumably reflect the animals’ assessment of how to best maximize reproductive success. In nature, the majority of prairie voles, Microtus ochrogaster, establishes pair bonds and engages in social monogamy while a minority of individuals remains single and presumably mates promiscuously. The existence of these two tactics raises the interesting question: do bonded male prairie voles choose to ‘settle’ (for just one partner) or are they preferentially ‘settling down’? To determine which of these two tactics is preferred, we provided single male prairie voles simultaneous access to two sexually receptive females for 24 h and then subsequently tested males in ‘partner preference tests’ with each female independently contrasted with a novel female. We aimed to determine whether males would form a pair bond with one, both or none of the original females. We found that males formed pair bonds with one of the two females. We also investigated male- and female-initiated aggression and found that during the bonding process males were more aggressive with females that they did not ultimately form a bond with. In the partner preference tests, males showed more aggression towards unfamiliar females than towards familiar females. Mismatches in male- and female-initiated aggression suggest that aggressive interactions may be perpetuated more by males than by females. Taken together, our results demonstrate that under conditions that are ideal for forgoing bonding and engaging in multiple matings, males choose to establish a pair bond, suggesting that selective pressures may have facilitated bonding by males.

Developmental trajectories and influences of environmental complexity on oxytocin receptor and vasopressin 1A receptor expression in male and female prairie voles

“…It is worth noting that the specific manipulation in the enriched context exposed males to three pairs of unrelated males and no females, potentially signaling that opportunities for bonding are low and that remaining single and mating opportunistically is the best possible avenue to maximize reproductive success. This hypothesis is consistent with the idea that non‐bonded prairie voles in nature might ‘choose’ to remain single and mate opportunistically based on the social context (Ophir, ; Ophir et al, ; Phelps & Ophir, ; Solomon & Jacquot, , but see Blocker & Ophir, ). It would also suggest that early life social experiences impact the neural mechanisms that subserve the decision to adopt particular reproductive tactics, or at least place males on trajectories that bias them to succeed within a given reproductive tactic (Okhovat et al, ; Ophir et al, ; Ophir et al, ).…”

INTRASPECIFIC KILLING EVENTS IN SIGMODONTINE RODENTS (Oecomys cf. cleberi AND Oligoryzomys nigripes)

“…Despite extensive literature on intraspecific agonistic behaviors for rodents of the Northern Hemisphere (e.g., Sadleir 1965, Scott 1966, Munger & Brown 1981, Wolff et al 1983, Petersen & Helland 2015, Blocker & Ophir 2016, few studies have been conducted on sigmodontine rodents (e.g., Courtalon et al 2003, Steinmann et al 2009, Bonatto et al 2013a, Petersen & Helland 2015, Bonatto et al 2017. Furthermore, this is the first study that reports intraspecific killing in free-living sigmodontines trapped in the same live-trap.…”

“…During behavioral observations of the dry vesper mouse Calomys musculinus (Rodentia, Cricetidae), males did not demonstrate aggressiveness during the breeding season, in contrast to females, that are territorial (Steinmann et al 2009). Surprisingly, male prairie voles Microtus ochrogaster (Rodentia, Cricetidae) are more aggressive to females in general after they bond to one, even if they are sexually receptive (Blocker & Ophir 2016).…”

Socio-Ecological Disruptions at Critical Periods During Development Alter Stress Responses and Hippocampal Dendritic Morphology of Prairie Voles: Implications for Social Monogamy

“…Like humans, prairie voles are designated as a socially monogamous species because the adult male and female pairs show a preference to live together but do not mate exclusively (Carter et al, 1995;Strassmann, 2003;Solomon et al, 2004;Streatfeild et al, 2011). Laboratory studies have shown that when male prairie voles are given the opportunity to access multiple mates, they show a preference to mate with only one of them (Blocker and Ophir, 2016). Although pair-bonded males are attentive to the sensory stimuli of other sexually-receptive females (Parker et al, 2011;Rodriguez et al, 2013), when given a choice, they prefer to remain in contact with their mate rather than a novel female (Blocker and Ophir, 2016).…”

“…Laboratory studies have shown that when male prairie voles are given the opportunity to access multiple mates, they show a preference to mate with only one of them (Blocker and Ophir, 2016). Although pair-bonded males are attentive to the sensory stimuli of other sexually-receptive females (Parker et al, 2011;Rodriguez et al, 2013), when given a choice, they prefer to remain in contact with their mate rather than a novel female (Blocker and Ophir, 2016). This suggests that males may be predisposed to forgo a desire to seek other mates once they form a pair bond.…”