When a female copper butterfly folds her wings, it sends the same message to males of her species that a wedding ring on a woman’s finger says to males of our species: “Move on, fellas. I’m not interested.”
A pregnant female copper butterfly, Lycaena phlaeas daimio, will fold up her wings when males pass by, if she wants to avoid amorous attention. This makes evolutionary sense, since both the butterflies only mate once in their lives.
A female could be injured if an unwanted male butterfly tries to mate with her after she has already been impregnated. At the very least, she would have to waste energy avoiding him. And the male would just be wasting his time and energy with her, since there would already be a caterpillar bun in her oven.
Since pregnant females close their wings after closing up shop, male butterflies keep on looking for love until they find a receptive partner, increasing the chances that all available females will become impregnated. Thus, the behavior ends up being a win for the species in general.
Jun-ya Ide, a professor of ecological engineering at the Kurume Institute of Technology in Fukuoka, Japan, first noticed the behavior in the wild.
Ide conducted an experiment to test the effects of male attention on female copper butterflies. He tested his hypothesis by moving a model of a male copper butterfly closer to a pregnant female. Sure enough, she closed her wings. Virgin females, on the other hand, didn’t.
“So, I concluded that since females don’t need more copulations, they close their wings to conceal themselves,” Dr Ide said in an interview with the BBC.
“The wing-closing behavior has evolved,” he said, “to avoid sexual harassment.”
The results are published in the journal Entomology.
IMAGE 1: The copper butterfly, Lycaena phlaeas daimio (Wikimedia Commons)