The purpose of "Mating pair" is to showcase males and females. In most species males and females are quite similar and one seldom has difficulty in identifying them as the same species. Indeed, telling them apart can often be impossible.
But some species the males and females may be so different they can only reliably be considered the same species if discovered "in copulo". And many more that are intermediate.

The purpose of this project is to showcase males and females of species with the aim to help identify them better, showing size and colouration and morphology of the two sexes