In Drosophila melanogaster (fruit flies), eye colour is controlled by a single gene located on the X chromosome.

• The allele for red eyes ($X^R$) is dominant.
• The allele for white eyes ($X^r$) is recessive.
• The Y chromosome does not carry an allele for this gene.

A heterozygous red-eyed female fruit fly ($X^R{X}^r$) is crossed with a white-eyed male fruit fly ($X^{r}Y$).

The Punnett square below shows the gametes of the parents:

What percentage of the total offspring from this cross is expected to be male with red eyes?