A female strawberry poison frog faces an abundance of choice when it comes time to breed. The forest floor is full of bright red males trying to attract her with their songs, and wrestling with other males to defend their territories. She could pick a suitor based on his size or health. She could weigh up the quality of his territory. She could judge him on the depth, volume or length of his croaking, any of which could indicate how strong he is.

Or she could just mate with the first male she finds.

That, rather anticlimactically, is exactly what happens. For all the effort that males put into attracting a partner, the only factor that seems to matter to the