Scavenging clean- up crew for live- food specialists

[Salmonsaladsandwich]

So, for a few days I've been keeping some chinese mantis hatchlings in a tall deli cup with a cotton- plugged feeding hole in the side. I'm having trouble attracting fruit flies so I've been feeding them tiny chironomid midges and other insects aspirated from a window at night. A problem I've encountered is that the midges don't last long those that haven't been eaten pile up dead on the bottom of the cup, but I still have to put a lot in to ensure each mantis gets enough food. It's a pain in the arse trying to remove the dead midges without opening the whole cup, and even then it's not easy. So, I was wondering if it would be a good idea to add some kind of scavenging insect to eat the dead midges that won't harm the baby mantises. So far a small carabid beetle, a cricket or an earwig come to mind but I feel like all of those might be dangerous.

So, does anyone have any ideas?

[NRoach]

Definitely don't use earwigs. I've had earwigs as part of a cleanup crew for my Blattella germanica and Blatta orientalis. They seemed fine at first until I caught them killing ecdysing individuals. Pill bugs are great and the mantises I've kept didn't really bother them. They need moist substrate and ventilation, though. Springtails will also keep dead insects from molding if there are enough, although I've had issues with their numbers getting too high. I'm not sure if too many springtails will disrupt baby mantids from molting, but I have had bad molts in enclosures where I keep small roach species when the wood slabs get completely covered in springtails.

[Salmonsaladsandwich]

I was planning on removing whatever I put in there once the mantids start showing signs of molting. I realize that basically anything that will eat a dead insect will probably eat a molting one.