Determinants of mating success in the golden hamster (Mesocricetus auratus): I. Male capacity.

Abstract

Rested adult golden hamsters produced a mean of 13 ejaculations and then showed a modified copulatory pattern consisting of long intromissions (10-30 s of intravaginal thrusting) during which no sperm transfer occurs. When a second (fresh) female was introduced, 58% of the males produced at least one more ejaculation, and 17% of the males produced one further ejaculation when placed with a third female. In similar three-female tests conducted 24 hr later, all males ejaculated (M = 4 ejaculations); this level of ejaculatory output was maintained over a subsequent 10-day period of daily testing. Four ejaculations ensured a nearly 100% pregnancy rate and maximum litter size in the first females. Second and third females, however, received fewer ejaculations and subsequently showed reduced fertility and produced smaller litters. Most males showed high levels of long intromissions on all days and with all females. The physiological significance of these long intromissions may be to trigger the progestational response. Examination of the rate of recovery from sexual exhaustion indicated that 2 or 8 hr of rest resulted in fewer than 50% of the males being capable of one further ejaculation. However, most of these single ejaculations were accompanied by long intromissions and resulted in successful pregnancies. Four to eight days were required for full recovery of ejaculatory capacity. This study showed that the male golden hamster has a higher ejaculatory output and more rapid recovery from sexual exhaustion than other small rodents that have been studied. Thus, the limits of male capacity appear to vary widely among species.

Sequential male mate choice under sperm competition risk

“…At the start of each experimental day, a pool of oestrus females was identified (based on vaginal cytology; Green 1966) for pairing with subject males based on a preallocated order of testing and ensuring at least a 7-day period between mating treatments for males to allow time for sperm replenishment (Stockley P, Edward DA, unpublished data; see also Jackson and Dewsbury 1979; Dewsbury 1983; Huck and Lisk 1985). All experimental pairings (up to 4 of which could be completed simultaneously) were conducted in high-sided enclosures (1.2 m × 1.2 m) supplied with food and water, and monitored remotely using CCTV equipment in an adjacent laboratory, with trials conducted in the morning (“early oestrus stage”) normally commencing between approximately 10.00 and 11.00 and trials conducted in the afternoon (“late oestrus stage”) between approximately 14.00 and 15.00 (the timing could not be fixed precisely owing to variation in the availability of experimental animals and the number of actual copulations on any one day).…”

Functional identity of the Gamma Tropomyosin gene

“…This observation is in agreement with a number of studies that show strain differences in fertilization ability for different mammalian species including mice, rats and hamsters. [31][32][33] In particular a poor fertilizing ability in vitro has been reported for various substrains of C57BL/6 mice when compared to other inbred and outbred strains, 34 an effect that has also been observed after artificial insemination, 35 ruling +/-clone with the Δ9ab construct the expected outcomes are a 9ab KO and homologously recombined alleles. (F) Genomic DNA isolated from ES cell clones was screened by PCR analysis using primer sets 9724F and 9b3'R to yield a 400 bp band and 9723F and 9b3'R to yield a 315 bp band.…”

Infrequent low dose testosterone treatment maintains male sexual behavior in Syrian hamsters

“…It remains to be established whether the minimalist replacement regimen described herein, and even more extended spacing between T injections, will affect the amount of sexual behavior males display before achieving sexual satiation (Arteaga et al, 2000) or the generation of long intromissions (Huck and Lisk, 1985). Our tests were terminated after a single intromission following the first ejaculatory series.…”