Singing, allogrooming, and allomarking behaviour during inter- and intra-sexual encounters in the Neotropical short-tailed singing mouse (Scotinomys teguina)

In this study we determine whether brief interactions with unfamiliar conspecifics stimulate audible singing behaviour in the Neotropical short-tailed singing mouse (Scotinomys teguina). Specifically, we examine whether intra- or inter-sexual interactions elicit singing in males in a neutral-arena design. We conducted two experiments. In experiment 1, we recorded singing behaviour of male subjects both before and after a brief exposure to a female mouse. Males significantly increased their singing behaviour after the exposure to the female, as compared to prior to the exposure. In experiment 2, we compared the singing behaviour of male test subjects after a brief exposure with one of three different treatment animals: a male, a non-oestrous female and an oestrous female. We found that males are most likely to sing after an interaction with a female, regardless of her reproductive condition. Male subjects sang significantly less following an interaction with another male. Although spontaneous singing is known to occur in males and females, opposite sex elicited-singing behaviour was found to be sexually dimorphic. An interaction with a male was not effective in eliciting singing in females. In experiment 2, we also recorded incidences of allogrooming and allomarking by males during the interactions with males, non-oestrous females, and oestrous females. Male allogrooming and allomarking behaviours using the mid-ventral sebaceous gland tend to occur more frequently during interactions with females as compared to males, but were significantly different only in the case of allogrooming. Thus, this study clearly suggests sex differences in singing, allogrooming and allomarking, and a likely relationship between these behaviours and courtship in this Neotropical rodent.