To feed flytraps things that aren't alive, first stick it in to trigger the trap and then gently squeeze the trap every ten minutes for the first hour or so, this will more the trigger hairs. After an hour or so the trap should stay shut as by this time the insect is usually dead.
Jaie, you mentioned a way of applying Superthrive I might try. The one about dabbing the inner surface of a trap with an ST solution on a Q-tip. Have you tried this yourself? I think the only hurdle would be fungus rotting the closed trap. And the things in ST aren't at all like what VFTs are used to i.e. insects. Insects don't contain vitamins and hormones!
Not to mention they generally don't look, smell, or taste as as gross as ST.
But it's good stuff!
Wouldn't it be cool if you could just farm insects on a diet that somehow tricks them into consuming superthrive? Then you could feed the bug to a trap and viola! A bug that DOES provide vitamins and hormones. Just trying to be difficult. hehe.
Sort of like gut-loading crickets before feeding to reptiles? That would ideal, sounds appropriate for a lab experiment. But the ST would need to be infused with whatever the insects like to eat. And you know what house flies like to eat... might make the ST smell even worse.