The long-tailed blue butterfly (Lampides boeticus) is believed to have been accidentally introduced to Hawaii in the 1880s. Accidental or not, it wasn’t a good thing. Its common name, bean butterfly, gives a clue as to the problem. It damages a wide variety of bean and pea plants, both domestic and commercial.
These photos were taken on the Puna Coast Trail in Hawaii Volcanoes National Park. The plant is Vigna marina or beach pea, an indigenous plant that grows well in the harsh, exposed coastal area that the trail passes through.
Graham's Island 
Gorgeous photos Graham. We get the Lampides boeticus here too, and I see that my little book on South African butterflies gives the common name as pea blue!
LikeLiked by 1 person
The names often seem to vary from place to place. I’ve seen books about Hawaiian butterflies where one uses one name and a second calls the same butterfly something different.
LikeLiked by 1 person
That’s the problem with common names I guess!
LikeLiked by 1 person