Mechanisms of sexual fidelity in the monogamous California mouse, Peromyscus californicus

Abstract

Peromyscus californicus are exclusively monogamous in the wild. We examined in the laboratory whether established pairs of male and female P. calijbrnicus would remain faithful when given the opportunity to mate with an opposite sex stranger, either in the presence or absence of their partner. When the partner was present she or he was tethered and could not intervene. Females in postpartum estrus (day 0 postpartum) preferred to associate with their pairmate rather than the unfamiliar virgin male. Females also preferred to mate with their partner, but 15-20% of the females mated with the unfamiliar male both in the presence and absence of their partner. Paired males were tested with an unfamiliar, sexually inexperienced estrous female on days 4 and 8 postpartum with their partners either absent or present but not in postpartum estrus, and on day 0 in the absence of their partner. Males preferred to associate with their pairmate. Contrary to theoretical expectations, males did not copulate with the estrous female when given the opportunity regardless of whether their partner was present or not. Furthermore, few males (2/13) tested in the absence of their partner mated with a sexually experienced, postpartum estrous female.These results indicate that monogamy in P. californicus is maintained by a strong attraction and preference of pairmates for each other and by self-restraint from mating with others. Male mate guarding may further ensure female faithfulness. Males exhibit apparently more sexual fidelity than females.

Pair bonding prevents reinforcing effects of testosterone in male California mice in an unfamiliar environment

“…The importance of the territory to PB California mice has been revealed in other studies; the winner effect (increased ability to win based on previous wins) developed in the home cage is later expressed in the home cage but not in an unfamiliar cage [30,31]. Owing to the higher salience of the territory over a neutral environment, PB males may decrease time spent in a neutral environment but increase the time spent close to their mates, which might be the mechanism of maintaining sexual fidelity and reducing the risk of extra-pair copulations [32]. Moreover, the T pulses induced by the interactions with female partners may also help enhance the proximity between PB animals [33] and further block formation of CPPs in an unfamiliar/neutral environment.…”

Aggressiveness during monogamous pairing in the sleepy lizard, Tiliqua rugosa: a test of the mate guarding hypothesis

“…Furthermore, male mate guarding is not always needed in monogamous species to ensure partner fidelity. Some species with no obvious mate guarding behaviour maintain genetic monogamy and are rarely observed in extra-pair copulations (Catry and Furness 1997;Schleicher et al 1997;Pierce and Lifjeld 1998;Robertson et al 2001;Wallander et al 2001), even when partners are absent (Gubernick and Nordby 1993). Thus male mate guarding is not always an effective mechanism to prevent extra-pair copulations, nor is it always required to maintain sexual monogamy.…”

Male fidelity expressed through rapid testosterone suppression of ultrasonic vocalizations to novel females in the monogamous California mouse

“…California mice re-pair with a new mate only after the disappearance of the mate in the wild (Ribble, 1991). In the laboratory, pair-bonded males, but not non-paired (sexually naïve) males, show reduced sexual advertisement to novel females via scent marking (Becker et al, 2010), and most individuals do not copulate outside the pair bond when given an opportunity (Gubernick and Nordby, 1993). Thus, California mice make an excellent model system to explore potential mechanisms of mate fidelity.…”