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

　　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, so the females sometimes try to get away -- or prefer to stay unobserved," 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 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, helping them avoid communication with their own species. We figured they were trying to avoid sexual harassment by males," Ide 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”。

　　红灰蝶全身黄黑相间。日本西部福冈市久留米大学副教授六月亚井发现，当雄性红灰蝶飞近时，一些雌性红灰蝶经常会合拢翅膀。

　　他补充说：“我们试图揭开谜团时发现，这些雄蝶在追求雌蝶，它们非常执着，因此雌蝶有时想要逃开，或者宁可躲起来。”

　　六月亚井和他的同事制作了一只雄蝶模型来靠近雌蝶，试探雌蝶的反应，结果发现，未交配过的雌蝶张大了翅膀，而已经交配过的雌蝶却把翅膀合上了。

　　他补充称，雄蝶对雌蝶不断的追求不仅会伤害到这些纤弱的雌蝶，而且在雄蝶穷追不舍时，雌蝶四处躲避雄蝶的骚扰，会过于疲惫甚至折寿。

　　他说：“合上翅膀可以让雌蝶不那么显眼，避免与同类红灰蝶的接触。我们认为它们是在躲避雄蝶的性骚扰。”