日本的小笠原琉璃灰蝶因受外來入侵物種的威脅，於2000年被列為瀕危物種。2005年起科學家嘗試人工繁殖但一直未成功，到近日他們的成蝶及幼蟲全部死亡，相信與近親繁殖有關。自2016年已無法在野外發現牠們，相信將會成為首種滅絕的日本蝴蝶。

A blue butterfly,Celastrina ogasawaraensis,  endemic to the Ogasawara Islands of Japan, was listed as endangered species in 2000; they were mainly threatened by invasive species. there are breeding program since 2005, but without any success, and all the adults and larvae were dead recently which might be caused by inbreeding. Since 2016, there are no field record of this butterfly and this species might be the first Japanese butterfly species to go extinct. 

https://english.kyodonews.net/news/2020/08/02f9a7c89582-butterfly-endemic-to-southern-japanese-islands-feared-extinct.html