Close up pictures of insects with flash

[Hans Bvckler]

Hello,

I like to take Close up pictures of insects with flash. The distance
between flash and the insects is down to 20 cm (normally 30 cm and
more).
Somebody in a butterfly garden (flash was not allowed) told me, that
butterflies can grow blind from flashlight.

Anybody who knows more about this topic?

Do insects "see" the flashlight?

Is it a lot of stress for the insects or is it like lightning?

Thanks
Hans

--
Hans Boeckler
E-mail: na408 at fen.baynet.de
Bindergasse 19, D-90403 Nuernberg / Germany
Tel. +49-(0)911-209877