Final answer:
Male mice do not adjust the X/Y sperm ratio based on female traits. In fruit flies, males prioritize larger females if sperm-depleted to improve reproductive success, which can shed light on behaviors potentially present in other species, although direct control over the X/Y sperm ratio by males is not substantiated by research.
Step-by-step explanation:
The X/Y sperm ratio variability in male mice does not provide a mechanism for males to adjust the concentration of Y-bearing sperm in response to female characteristics such as perceived masculinity or fecundity. Contrary to the information provided in the erroneous claim that the ova have specific receptors for X or Y spermatozoa, the fertilization process does not work like that, and there is no evidence to suggest that male mammals can selectively alter their sperm ratios in real time based on the type of females they encounter. However, interesting behavioral biology findings suggest that male fruit flies, which can be a proxy for understanding other species' reproductive behaviors, show selectivity based on their own physiological state. Resource-depleted males, or those with lower supplies of sperm due to previous matings, are known to prefer larger, more fecund females, thus maximizing their reproductive success with the limited sperm they have available.
Regarding sexual reproduction in mammals, both male and female gametes contain a single sex-determining chromosome; male gametes can carry an X or Y chromosome, while female gametes contain only an X chromosome. This process ensures the offspring will either be male or female based on whether an X or Y carrying sperm fertilizes the egg, but there is no switching mechanism for the X/Y ratio in sperm based on mating conditions.