Resumen:
The reproductive activity of reptiles is typically assessed using monthly sampling. The spermatogenic cycle of Sceloporus variabilis was recently assessed using the aforementioned methodology, and only two spermatogenic phases (recrudescence and maximum activity) were observed. The authors hypothesized that quiescence and regression must occur in a short period (less than a month), which was not visualized by their monthly sampling methods. Thus, the entire spermatogenic cycle displayed by this species may have not been adequately represented. The present study assessed the spermatogenic cycle of S. variabilis in those months where the spermatogenic activity passes from maximum activity (July) to recrudescence (August) using weekly sampling to test the hypothesis that quiescence and regression do indeed occur. The results showed a regression period for 2 weeks, whereas quiescence was not observed. These results lead us to two hypotheses: (a) quiescence occurs in a very short period (days/hours) or (b) does not occur in this species. The data generated in this study suggest that species exhibiting rapid changes in spermatogenic activity need to be assessed at more frequent intervals to accurately depict the spermatogenic stages.
Descripción:
Los reptiles presentan una gran variedad de patrones reproductores, que, en el caso de los machos, van desde diferencias en la duración del ciclo reproductor (Huang, 1997; Lozano et al., 2015), la época (primavera y/o verano, época de lluvias y/o sequía) en que se lleva a cabo (Vitt y Goldberg, 1983; Ramírez-Pinilla, 1991; Ferreira et al., 2002; Goldberg, 2008) o si la actividad es continua o estacional (Méndez-de la Cruz et al., 2015). La actividad reproductora continua, es aquélla donde la producción de espermatozoides es constante durante todo el año y aunque suele ser asociada a especies tropicales (Sherbrooke, 1975; Vial y Stewart, 1985; Van Sluys, 1993), se ha registrado en especies de clima templado (Hernández-Gallegos et al., 2002; Lozano et al., 2015). En contraste, la actividad reproductora estacional es aquélla donde los machos llevan a cabo la gametogénesis en periodos específicos del año, generalmente en primavera o verano/otoño, y está típicamente asociada a especies de clima templado (Abu-Zinadah, 2008; Goldberg, 2011; Rheubert et al., 2014). De igual modo, la actividad reproductora estacional también ha sido registrada en especies tropicales (Ochotorena et al., 2005; Granados-González et al., 2017).
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