Effect of Sociosexual Experience and Aging on Number of Courtship Ultrasonic Vocalizations in Male Mice

Abstract

Sexual behaviors are instinctually exhibited without prior training, but they are modulated by experience. One of the precopulatory behaviors in adult male mice, courtship ultrasonic vocalizations (USVs), has attracted considerable academic attention recently. Male mice emit ultrasounds as courtship behavior when encountering females. However, the modulatory effects of experience on USVs remain unclear. In the present study, we aimed to clarify the effects of sociosexual experience and aging on adult male vocalizations. First, we examined the effect of aging. The number of USVs decreased in an age-dependent manner. Following this, young adult male mice were co-housed for two weeks with normal female mice or ovariectomized (OVX) female mice, or housed without female mice, and the number of courtship USVs before and after co-housing were compared. In males housed with normal or OVX females, USVs increased significantly after co-housing. In contrast, males housed without females did not exhibit a significant increase of USVs. A facilitative effect of co-housing with female mice on vocalizations was also observed in aged males. In addition, females used as co-housing partners became pregnant, and the reproductive rate may be related to the vocal activity observed in the partnered males. These results indicate that sociosexual experience and aging affect vocalization activity, which may be related to courtship and/or reproductive function.

USVSEG: A robust method for segmentation of ultrasonic vocalizations in rodents

“…Mice. We obtained 10 recording sessions of courtship vocalizations from 6 mice (Mus musculus; C57BL/6J, adult males), under the same condition and recording environment as described in our previous work [38]. Briefly, the microphone was set 16 cm above the floor with a sampling rate of 400 kHz.…”

“…Mouse USVs can be discriminated into several subcategories according to their spectrotemporal patterns [31][32][33][34][35], and these patterns could predict mating success [35,36], though subcategories are not consistent between studies. Their USV patterns are innately acquired rather than a learned behavior [34,37], though sociosexual experience can slightly enhance the vocalization rate [38]. In rat USVs, the pleasant (~50 kHz) and distress (~22 kHz) calls have been suggested to have a communicative function since these calls can transmit the emotional states of the vocalizer to the listener and can modify the listener's behavior such as mating [26,39], approaching [40], or defensive behavior [41,42].…”

Ultrasonic vocalizations in house mice depend upon genetic relatedness of mating partners and correlate with subsequent reproductive success

“…However, it is unclear whether male USV emission influenced male mating success, or vice versa. Second, Kanno and Kikusui [21] recorded males with a novel virgin female both before and after they were housed with another female for 2 weeks. They compared males that emitted USVs with males that did not vocalize before or after co-housing, and they found that vocalizing males sired more offspring than non-vocalizing males during the co-housing phase.…”

USVSEG: A robust segmentation of rodents’ ultrasonic vocalization

“…Mice. We obtained 10 recording sessions of courtship vocalizations from 6 mice (Mus musculus; C57BL/6J, adult males), under the same condition and recording environment as described in our previous work (Kanno and Kikusui 2018). In brief, the microphone was set 16 cm above the floor with a sampling rate of 400 kHz.…”

“…Mice USV has been suggested to be distinguished into several subcategories according to their spectrotemporal patterns [30][31][32][33][34], and this pattern could predict mating success [34,35], while the subcategories were not well consistent between those studies. Their USV patterns are innately acquired but not learned behavior [33,36], though sociosexual experience can slightly enhance the vocalization rate [37]. In rats USV, the pleasant (~50 kHz) and distress (~22 kHz) calls have been suggested to have a communicative function since these calls can transmit the emotional states of vocalizer to listener and modify listener's behavior such as mating [25,38], approaching [39], or defensive behavior [40,41].…”