In fact, the male Photinus flies come to a sticky end. The Photuris females are not looking for a loving embrace but for something to eat. The male Photinus has defensive chemicals in his blood the Photuris needs to repel predators like spiders and birds.
By devouring the hapless Photinus male, the female Photuris arms herself with the vital chemical. Experiments showed that when Photuris fireflies have eaten Photinus fireflies, hungry spiders reject them.
The findings were published in the journal Proceedings of the National Academy of Sciences.Reuse content