One kind of female butterfly mates only once in its life -- and then closes its wings to avoid "harassment¹" when pursued by persistent² and unwanted males, a Japanese researcher said.

日本一位研究人员称，雌性红灰蝶一生只交配一次，在其它雄性红灰蝶不停地追求它时，它会合上翅膀躲避这种不必要的“骚扰”。

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Female copper butterflies mate once in their life
Observations of the Small Copper Butterfly, a colourful orange and black butterfly, showed that some females closed their wings when males flew by, but only when they were males of their own species, said Jun-Ya Ide, an associate professor at Kurume Institute of Technology in Fukuoka, western Japan.

"When we looked into why, the males were courting the females. They do this very stubbornly（顽固地） , so the females sometimes try to get away -- or prefer to stay unobserved（未被注意的） ," he added.

Ide and his colleagues brought a model of a male butterfly near the females to test their reactions and found that young females that had yet to mate kept their wings open, but those that had already mated closed them.

Not only can the persistent（固执的，坚持的） attentions of unwanted suitors harm the delicate females, fleeing from them -- with the male often in pursuit -- uses up strength and can even shorten their lives, he added.

"Closing their wings makes them less visible, helping⁴ them avoid communication with their own species. We figured they were trying to avoid sexual harassment by males," Ide said.