How does the mulberry tree relate to the theme of the passage?

Thisbe, after a brief period of mourning, stabs herself with the same sword. In the end, the gods listen to Thisbe's lament, and forever change the color of the mulberry fruits into the stained color to honor their forbidden love. Pyramus and Thisbe proved to be faithful lovers to each other until the very end. You can check this out in greater detail below:

https://en.wikipedia.org/wiki/Pyramus_and_Thisbe