Seasonal variations of male reproductive parameters of Tomodon dorsatus from Southeastern Brazil

Variações sazonais dos parâmetros reprodutivos do macho de Tomodon dorsatus do sudeste brasileiro

ABSTRACT:

The morphology of the male reproductive tract of Tomodon dorsatus was described in the austral seasons of the year considering macroscopic and microscopic variables. For this purpose, 56 specimens from the herpetological collection of the “Instituto Butantan” were used. Fragments of the testes, kidneys and ductus deferens were collected and submitted to histological routine. The peak of the testicular volume was observed in the summer and the epithelium of the seminiferous tubules had higher height in the summer (p=0.001). The testes were active throughout the year, however, the spermiogenesis peaked in the summer. There were spermatozoa in the lumen of the ductus deferens in all seasons of the year. Renal length was higher in autumn (p=0.027), and renal width did not show a significant increase (p=0.237). The diameter and epithelial height of the sexual segment of the kidney (SSK) showed hypertrophy in winter and spring, coinciding with the mating period. Based on findings of this study, we can suggest that, at the population level, the reproductive cycle of T. dorsatus can be considered seasonal semi-synchronous, due to the peak of spermiogenic activity in the hot season, and discontinuous at the individual level.

INDEX TERMS:
Reproduction; Tomodon dorsatus; Brazil; snake; sexual segment; kidney; testis; wildlife animals