Polyphaga sp. oothecae..?

Vys

Arachnoprince
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Sep 22, 2002
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Helo.

I acquired these Polyphaga spp., collected in Armenia, some time ago, and they have since dropped a number of what I believe must be oothecae. Now, in six months or so, I've not seen any trace of any nymphs, so I've isolated a couple of these presumed eggsacs and tried keeping them a bit warmer, as well as a bit warmer+wetter, to no effect.

I'm obviously no biologist, and if anyone has any insights to share regarding these creatures, I'd be happier.

Edit. It would perhaps be of interest to know approximately the conditions under which they are kept:
Around 24C, mixture of peat/compost maybe 2" deep, sprayed a few blasts every fourth day or so.

Attached are three (bad) pictures, for reference. In descending order:
Adult female
Presumed oothecae-on-a-stick
Adult male.
 

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xelda

Arachnobaron
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You might find this article helpful: "Bionomics of a desert cockroach, Heterogamisca chopardi Uvarov, 1936 after the spring rainfalls in Saudi Arabia (Insecta, Blattaria, Polyphaginae)" by Philippe Grandcolas. Journal of Arid Environments (1995) 31:325-334.

It's based on a field expedition to learn more about desert cockroaches. Granted, it focuses on a different species in a different part of the world, but it's the same family (Polyphagidae) as the Polyphaga sp. and shares many physical similarities. After reading the article, I gave my polyphagids several more inches of substrate, but that still doesn't seem to be deep enough for any of them. Nevertheless, I try to offer them what I can by giving temperature, humidity, and sand ranges so the roaches themselves can pick whatever feels more comfortable to them. My Arenivaga sp. deposited a few oothecae all in the same spot at the very, very bottom of the cage. I'm assuming that must have been a good spot to them, so I just left them there and try to keep the temp and moisture conditions somewhat consistent there. I also left the oothecae alone so I have no idea if they've hatched yet. I normally don't even look for oothecae but I happened to find these because I thought I saw a dead roach at the bottom of the cage.

I try to avoid handling any oothecae in general because they're easy to damage. Those little "teeth" along the side are little air chambers for the developing embryos--one chamber per embryo. If the chamber breaks off, the embryo dies, and if too many of them break off, the entire egg case dies. That, and it seems harder to try to hatch oothecae myself rather than leaving them in the cage.
 

Vys

Arachnoprince
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Thanks for your answer.

Interesting information regarding the oothecae 'teeth'. I am very careful in handling them, but perhaps I should just let them be where they are dropped.

Sometimes that seems to be on top of the substrate, sometimes buried in it; whatever is the case they just don't seem to want to hatch.


So far, I've only concluded that they're very much night active, appear to rather dislike misting, and will, in addition to bran, sometimes eat apple too (though they seem to mostly enjoy pooing on it and burying it).

Depth eh? I have a few large critter keepers left over..I'll give the remaining ones depth. But meh, heatmat-heat will make their world seem even more inverted then.

Will attempt to locate that article too.
 
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Takumaku

Arachnoknight
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Feb 27, 2006
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In addition to bran, my loved to eat oatmeal, and musli (Swiss-Style Cereal).

Substrate:
Maybe I just had bad luck, but I lost one of my colonies that was housed in a carnivorous soil mix (1 : 1 peat moss, sand). Maybe it was bad luck, but after switching this colony, within two weeks, all of them were dead.

But the other colony is still doing fine. They are housed in a basic top-soil mix (1 : 1 : 1 compost,topsoil, sand). They seem to prefer to eat the compost over everything else. Maybe this has something to do with the death of the other colony. idk, but once I come up with some play money, I'll test it.
 

Vys

Arachnoprince
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Carnivorous soil mix?

Anyways, I wonder if a standard light bulb right above a kritter keeper would be a more natural heat source? (During the day.) Or would it just be too hard then to keep it moist enough? Would be nice to know just how much of that they need. Hmhmhmm.
 

Takumaku

Arachnoknight
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Feb 27, 2006
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My other hobby is growing carnivorous plants (pitcher plants, sundews, bladderworts, etc.). Because of their growing conditions, they need a fast draing, nutrient deprived soil mix. A basic CP mix is an equal ratio of peat moss to sand or peat moss to perlite. Since I also grow vegetables, and make my own soil mix for them too, it's easier for me to label which soil I'm using by the plant that is designed to grow in it.
 
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