Hmmm, can certainly see why there's suggestions of looking stuck on. Think it's a combination of things which in isolation wouldn't necessarily impact but here are reinforcing the feeling: poor DOF, high contrast, a touch oversharpened (maybe) but mainly that there is nothing to connect flowers to Red Admiral. Butterfly needs something to relate to flowers; whether it be to face them, angled to them or in amongst them.
You say you've others - any that alter any of the above as I'd love to see a shot that sat comfortably with me of a Red Admiral on Snowdrops, if only for it's unusuality?!
