Red runner colony issues: Parasitic flies? And roaches not reproducing?

[PlayingMantis]

Over a month ago I bought 1k adult red runner roaches, and about half arrived dead, so I still had 500 which I put in a 10 gallon glass tank with soil substrate, egg cartons, and the roaches were fed dog food and fresh veggies. I've seen a lot of eggs but no baby roaches. The adults have been dying off slowly. I've seen many headless dead roaches littered across the bottom of the enclosure, and I assumed it was because I hadn't been feeding the roaches enough (because I've been really busy with other things lately), so they were cannibalizing each other.

Now the strangest thing happened yesterday. I woke up to find about a dozen flies, which looked like house flies, flying around inside my home. I only use BBFs, and I have no house flies. I keep my doors and windows closed so the flies couldn't have gotten inside from outdoors. I was stumped. Today I found more loose flies flying around. I looked closer at my roach tank and saw more flies inside the tank, so I guess the flies originated from inside there, and some escaped through the cracks that cover the top of the tank.

So 2 questions:

-Why are the my roaches not reproducing? I see roach eggs but no baby roaches at all.

-Where did the flies come from? Have you heard of parasitic flies (tachinid flies) infesting roach enclosures? Is it possible the fly larvae had been growing inside the roaches and have now grown into adults? This is really concerning because I don't want the flies getting into my mantis enclosures and parasitizing my mantises!

 

[PlayingMantis]

Oh my goodness. I took a closer look at the substrate and I see tons of hairy grayish larvae that have 6 legs and are lighter colored on the underside. They walk pretty fast and can climb plastic surfaces. I don't know how these are related to the flies, since flies should come from maggots, which shouldn't have legs??

And yes, I have been neglecting my roach colony lately because I'm been so busy. There are lots of dead roaches on the bottom that I didn't clean up, and the larva seem to be eating them.

I attached a picture, can someone tell me what the heck are these things?

 

[CosbyArt]

I don't keep roaches, so I can't help you with those questions.

The larvae in the Dixie cup though appears to be a dermestid beetle larvae - take a look here and see if it is that. I know with crickets the beetle/larvae are common at the pets stores and with some keepers, and are used to eat the dead crickets and occasionally I get a few (and could be very likely a few were mixed in with your roaches). I personally would like to be able to keep them, but they tend to die out quickly as I typically only get a couple at most.

 

[Krissim Klaw]

Yep, the larvae are harmless and only eat already dead roaches. My guess is the flies you are probably seeing are some sort of phorid fly. They can be annoying but you would need extreme numbers to grind your colony to a halt. My guess is the eggs might just need a bit more time before hatching.

 

[guapoalto049]

Keep the dermestids at bay, they can eat pinned collections! Learned this the hard way

 

[hibiscusmile]

yup, all true, all true!

 

[Hisserdude]

Hmm, what temps are you keeping your red runners at? Your care seems to be good, it may just be taking the ootheca a while to hatch. Are the ootheca being kept humid?

As for the flies, it is within the realm of possibility that they are tachnid flies, as I have had a WC Parcoblatta nymph paratisized by one, but it is very unlikely. Also, any tachnid fly that eats roaches will probably not eat mantids, these things can be picky when it comes to their hosts. Got any pictures of the flies?

Those are indeed dermestid beetle larva, and are good cleanup crews for roach colonies, they eat the dead roaches. Some people will buy them to put in their colonies, so the fact that you got some for free is pretty cool.