Resumen

CORTES-CALVA, Patricia  y  ALVAREZ-CASTANEDA, Sergio Ticul. Tamaño gonadal de machos de Chaetodipus arenarius (Rodentia: Heteromyidae) durante un ciclo reproductivo en Baja California Sur, México. Rev. biol. trop [online]. 1999, vol.47, n.3, pp.617-622. ISSN 0034-7744.

The description of reproductive activity in small nocturnal mammals is difficult. In this study we use the variation of testis characteristics over time. From February through December 1993 we set 1628 traps/night for the capture of specimens. We were studying the variation of testis size of 30 Chaetodipus arenarius sublucidus, and analyzing the morphometric characteristics and morphology of the sperm of this species compared with C. spinatus. We recorded the abundance of sperm per age. The size of the testis was greater from February through September, during which there was reproduction activity, and this corresponds to a larger amount of sperm. There were morphometric differences in the length size of sperm. The gonadal-somatic index indirectly indicated the reproductive activity.

Palabras clave : Rodentia; Heteromyidae; reproduction; gonadal-somatic; sperm; Baja California Sur.