Meeting Abstract

P2.2  Tuesday, Jan. 5  Androgens activate advertisment songs of Neotropical singing mice (Scotinomys) PASCH, Bret*; GEORGE, Andreas; HAMLIN, Heather J.; GUILLETTE, JR., Louis J.; PHELPS, Steven M.; University of Florida bpasch@ufl.edu

Androgens are important hormones that mediate vocalizations associated with sexual behavior and aggression in many vertebrates. However, the influence of androgens on mammalian vocalizations is not well characterized, especially in non-model organisms. We manipulated androgen levels in Alston’s singing mouse (Scotinomys teguina) to elucidate hormonal control of singing and aggression. Singing mice are diurnal insectivorous rodents that inhabit montane cloud forests of Central America. Males commonly emit an audible (dominant freq. ~22 kHz) stereotyped song that appears to function in male-male aggression. Adult males were assigned randomly to 4 treatment groups: castrate plus empty implant, castrate plus DHT implant, castrate plus 1mm testosterone, and castrate plus 2mm testosterone. Implants and castrations were performed synchronously, and animals were tested 14 days before and after surgery. We recorded spontaneous song rate, measured response to a conspecific song, and presented intruders to the home cage of focal animals pre- and post-treatment to assess changes in aggression. Mice with empty implants sang less, had longer latencies to respond to conspecific song, and engaged in more submissive displays. Conversely, mice with DHT and testosterone implants increased song rates and showed no differences in aggression pre- and post-treatment. Our results indicate that androgens maintain song and that hormonal state shapes motivational state in singing mice.