When humans look for a partner with whom they want to have a relationship, we usually list the qualities to which we are attracted and what we want to see in our partner. There are some qualities that may be negotiable while there are things that you probably wouldn't compromise. But for certain species of Heliconian butterflies, they have quite strict criteria for finding their mate.
Complex and diverse, Heliconian’s wings patterns have drawn the attention of artists and scientists alike. And yet, each distinct species maintains its own unique pattern through generations. Scientists always wondered exactly how the species manage to preserve and maintain these patterns—and don’t cross-breed with each other.
One obvious reason is that Heliconian males are very picky when it comes to choosing their mates. A male will only woo a female butterfly that looks like him—meaning that she has the same color patterns as him. That’s why the red-spotted species react to Jiggins’s red cloth. Scientists knew that this specific reproductive trait drove the butterflies’ speciation, but the exact genetic basis governing their mate selection was unclear until recently.
(Image credit: University of Cambridge)