Timing of Mating, Sperm Dynamics: DISCUSSION(3)

DISCUSSION(3)

No other field data are available on length of copulation in this species. However, recent captive mating trials, both with and without competing males, showed that ejaculation in this species occurs sometime between the first and third hour of mating, adding further weight to the argument for the existence of lengthy copulations in the wild in this species. flovent inhaler

In captive and wild populations of the agile Antechinus, sperm production is restricted to a brief period prior to the mating season, and the epididymis has limited capacity for sperm storage. The continual loss of spermatozoa via spermatorrhoea observed in captive studies, even in unmated males, further depletes sperm reserves. It has been suggested, therefore, that few sperm (~3.5 X 106 spermatozoa per side) are available for mating at the commencement of the rut and even fewer remain at the conclusion of this period. This was confirmed in the present study, in which very low numbers of testicular and epididymal spermatozoa were found in males captured immediately after the rut.

The reproductive tracts of mated females caught during this study also contained relatively few spermatozoa (1.7 X 103-75.5 X 103 spermatozoa per side) in comparison with values for other mammals. This supports previous captive mating studies indicating that relatively few spermatozoa (< 40 X 103 spermatozoa per side) are delivered at ejaculation and subsequently colonize the female reproductive tract in the agile Antechinus. Sperm transport and storage in the female reproductive tract of this species postmating are highly efficient, and captive and field studies show that relatively few spermatozoa are required for successful fertilization.

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