Fresh dead flies are fine, but you need to place them in the 'mouth' in such a way that the thick trigger hairs are touched properly (two at least), thereby causing the leaf to close and the cillia to interlock correctly. Even with tweezers this can be a tricky operation. If you haven't done it properly the seal won't be good enough and it can get an infection.*
Also, don't keep triggering the hairs just to see it close as this can lead to deathsville for the plant.
*This is all from memory and might be utter codswallop.
Also, don't keep triggering the hairs just to see it close as this can lead to deathsville for the plant.
*This is all from memory and might be utter codswallop.