GANSER, Lisa R.; University of Miami: Sex differences in the hindbrain of the cane toad, Bufo marinus

Sex differences in morphology and reproductive behavior in anurans are often easily defined. The neuroanatomical areas that govern these sexually different reproductive behaviors are not as easy to discern. In many anuran species, males will attract mates by calling. Though females are able to emit sound, most do not vocalize for the purpose of attracting a mate. The cane toad, Bufo marinus, is a species for which the males attract females by calling. The laryngeal motor nuclei associated with mate calling are found in the caudal medulla of the brain. I found sex differences in these hindbrain areas of B. marinus. Previous studies by Kelley (1988), Kelley et al. (2001), and Yamaguchi and Kelley (2000) pinpointed similar neuroanatomical sex differences in Xenopus laevis. I used several histological methods for nucleus identification and analysis including Cresyl Violet stain for light microscopy and fluorescent Nissl stain and the retrograde tracer, DiD, for confocal microscopy.