A positive Link Between Male Testosterone and Spacing Behavior in Pair‐Bonded California Mice

Abstract

The effects of testosterone (T) on male sexual behavior are well established, but its roles in several associated social behaviors such as pair‐bonding and paternal behavior are diverse. Recently, we reported that male T in response to pairing with a female predicts future paternal behavior in the monogamous and biparental California mouse (Peromyscus californicus). Here, we examined whether T in response to pairing is also associated with spacing behavior between mates under laboratory conditions and if these behavioral patterns are continued during pup care. Pairs of California mice were observed throughout their pair bond before and again after pups were born. We found that males with higher T post‐pairing remained closer to their mates in the weeks before pups were born, and pairs with higher proximity measures during the pair bond spent more time caring for pups together. Overall, these results suggest a similar mechanism for spacing behavior across distinct phases of the pair bond.

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

“…The present results are consistent with the latter hypothesis since T reduced the total number of USVs produced by pair bonded males, primarily driven by a reduction in the number of simple sweeps. This hypothesis is further supported by previous studies in our model species, specifically that high T in pair bonded males is associated with increased proximity to the mate (Gleason and Marler, 2012a).…”

“…However, we propose an alternative hypothesis: T pulses may strengthen the pair bond by attracting a male to his partner and/or inhibiting extra-pair mating effort. This idea is supported in part by findings in P. californicus illustrating a positive association between high T levels in males and close proximity to their mates (Gleason and Marler, 2012a). To extend the study of variation in behavioral response to rapid T effects, we also examined within-species variation by contrasting sexually naïve, non-paired individuals and paternally experienced, pair bonded individuals within the monogamous California mouse.…”

Testosterone pulses at the nest site modify ultrasonic vocalization types in a monogamous and territorial mouse

“…One possibility is that T is increasing male sensitivity to environmental stimuli. For example, the increase in both 1SVs and 4SVs and a lack of an increase in barks could reflect an increase in affiliation and/or sexual attractiveness to females at the T nests as suggested by a negative association between male T and distance between the male and his mate (Gleason & Marler 2012). Laboratory studies reveal a positive association between the production of SV calls, SV bout size, and SV call duration of the male/female dyad with male affiliative behavior, such as when a male follows the female mate (Pultorak, Matusinec, Miller, & Marler, 2017 In the field, SVs are the most common call type detected, but occur both when individuals are alone or during social interactions (Briggs & Kalcounis-Rueppell, 2011).…”

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

“…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. The variation in T functions between SN and PB males may underlie the plasticity of behavioural reinforcement in the neutral environment and orient males to allocate more time in the salient environmental cues in which the display of T-related behaviours are important for individual fitness.…”