# Fly larvae infestation in my roach colony



## Herpetologydude (Nov 19, 2010)

Hey everyone,

I have been raising a colony of B.discoidalis for several months now. Throughout the end of October up to today I am finding a constant influx of Small white what I assume are fly larvae. I'm also noticing a high mortality rate in my adult roaches, along with some levels of wing disfurgement when adults molt into their mature stage.

Any ideas on these problems? Could they connect to humidity? Any idea on what kind of Larvae these are and if they are parasitic? I have cleaned out my container twice in two weeks washed it down and still they continue popping up, I'm assuming the adult flies are gaining access through an open window or something unless these are indeed parasites.

Here are some (poor quality) pictures of the larvae, the camera wasn't cooperating well tonight :/

Thanks for any future replies!


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## briarpatch10 (Nov 19, 2010)

I keep my B.dubia in a 20 long tank wit a mesh lid... I have never had a "pest" problem . The wing disfigurement I was told is male on male fighting over females. how large is the container and do you have egg crates to keep them seperate?


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## Herpetologydude (Nov 19, 2010)

I'm keeping them in a 30 gallon tub with a slit cut in the middle of the top where I installed screen for proper ventilation. I have a few egg cartons in there as well (would like some more though), I'm beginning to wonder if the number of roaches are becoming to much for the size of the tub.


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## TheBugBarn (Nov 19, 2010)

Strange, I am having the same problem. Adults just dropping off. And this is only occuring with my discoids. I keep 13 kinds of roaches in the very same room. I can't find maggots in there, but the bin seems to always be full of fruit flies.
I've recently completely removed the lid of the bin. Thinking it might be a ventilation issue. Discoids aren't climbers at all, so escapes not a problem. If this helps, I will let you know.


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## ZephAmp (Nov 19, 2010)

I want to say those are Megaselia scalaris larvae. A pupae/ pic of an adult or two would really help!
They are most likely feeding on the dead roaches which are dying for unrelated reasons. Wing deformities are often caused by overcrowding and not enough food.


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## Galapoheros (Nov 20, 2010)

I get fast die-offs with adults also but it seems to be a "generation" thing to me, getting old at the same time, but with 1000's of young underneath the bark I keep with them.  The adults die then phorid flies show up, ...with larvae, but all that goes away after some weeks.  I have mine in tall plastic tubs, no top, the males I have can't make it to the top.  Sometimes the males try as if swarming, thump, thump, thump, ...they just can't do it.  I've had them for years and have never cleaned the tubs except for taking out dead bodies.  Isopods and some water dumping have worked together to break things down in there, no smell, I add oak leaves now and then.  I wonder if you have it too wet, soaking food and attracting flies(?)


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## jezzy607 (Nov 20, 2010)

Sounds like Phorid Flies to me. I get them almost every fall as well. As far as I know they are not parasitic although they will start ovipositing on roaches that are not completely dead (but well on their way). The life cycle is extremely short, so numbers can explode within a week or two depending on temps. They seem to cause higher rates of mortality once they infest a roach colony, because infested carcasses become juicy, smelly, and messy, causing relative sanitation to decline rapidly which I think affects weak members of the roach colony.

The best solution is to keep the containers even drier than normal and to have maximum ventilation for a few weeks until adult flies are no longer noticed.

They can easily be differentiated from fruit flies because they run rapidly around just as much as they fly, fruit flies kind of "hover" around and do not dart around on their legs like the Phorids. Phorid flies are also known as "hump-backed" flies. I hate them.


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## Vfox (Nov 21, 2010)

I've always noticed phorids when my tanks are too damp and a few dead remain. I now change food and water gel once every three days, never soak the substrate but mist twice a week, and pull any dead I find. I have ten species right now and have seen one phorid last month. I killed it, cleaned the tank, and haven't seen one since. Good luck!


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## Stylopidae (Nov 21, 2010)

There's really no way to identify the larvae to family (much less species) with the information you've given because you need to see things like head capsule structures and spiracle structures to have a shot at identifying them. I can tell you from the reduced head capsule that you're dealing with some sort of Brachycera larvae and that the likely candidates are Phorids, Calliphorids, Muscids, Drosophilids, and Sarcophageids which are the most commonly encountered decomposers.

My bet is that they're some sort of Phorid or Drosophilid, depending on what that unidentifiable mush is in the picture. I'm basing this on the moisture in the picture and I'm guessing you're feeding them wet dog food, so my guess also leans towards Phorid fly larvae. You're probably going to see them around feeding areas if my hunch is correct.

Take the food out for a few days and replace it with a large container of dry food in the meantime. Allow the cage to air out and dry out...clean if you need to. Use fruit, vegetables, or wet dog food to water your colony from now on and keep it in a removable container.

Good luck


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## Herpetologydude (Nov 21, 2010)

Thanks for all the replies,


I went from using Fruit as my primary food and water source to gel crystals and various dry dog/cat foods. Been the same results thus far, still getting larvae and moisture condensation in the enclosure sadly, I'm thinking I might need to add some ventilation to keep the humidity levels from building. 

I'm just glad they do not seem to be parasites! I'm guessing they are some sort of Phorid fly now based upon the information provided.

Thanks again for the suggestions guys, i'm switching back over to fruit today for sustenance and hopefully I can dry out the cage within a few days.


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## J Morningstar (Nov 22, 2010)

remember that you don't need to give them any water if their food is moist...and those crystals are iffy at best.
I just had the same problem, but I know I am grossly overpopulated. all substrate removed, wood peices throughly scrubbed, food now only placed on ceramic dishes. Result? Happier.


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