Issues with raising Dubias

[bugboymark]

Question for any roach culture experts out there. I bought 2 dozen dubia nymphs 11 months ago.  I now have 5 (3 female: 2 males).  The ones that are gone were fed to mantises that reached maturity and have since passed. Really amazing is that I didn't lose a single roach to anything other than feeding. Impressive bugs.  Now I know why they'll be around after we're gone!  Anyhow, I've got 4 mantises now that will soon be big enough to eat roaches.  Here's my issue....I can't seem to get them to reproduce! They regularly produce ootheca, but then discard them without any nymphs/hatchlings.  My setup is:

Plastic bin - 16" x 16" with a screen top for ventilation, substrate eco-earth (coconut fiber/husk), cardboard egg carton for shelter, water gel, cricket food + fresh fruit (usually apples), heating pad to keep the temp in the upper 80s, occasional misting to add a little humidity, no-heat lamp or direct light source...though I did use a heat lamp for a while with no success. 

They look healthy. They're eating. They're producing ooths weekly. The female to male ratio seems pretty close to what is recommended to avoid competition.  What am I missing?  Why can't I get these guys to produce viable offspring?  Thanks for any advice you can provide!  ?

 

[Aristalochia]

Hello bugboymark,

Blaptica dubia arent supposed to lay ooths, so if you are seeing them all aborting their oothecae/dropping them, it means something is way off. I am not sure what the issue is, but have you tested your humidity? If it gets too low, that might explain it, although many keep dubia relatively dry without substrate, so maybe someone else has a better suggestion?

 

[bugboymark]

Good catch.  That was my bad.  I was mixing my species.  I actually was having issues getting TWO roach species to reproduce. My Dubias (live birth), AND my turkish red runners (ooths).  Thankfully another member of the forum (ausar318) sent me a TON of information about his setup and his success with these roaches.  He also sent me a bunch of dubias that are already are reproducing for me!  As for my red runners (Blatta lateralis), I got lots of ooths but no nymphs over 3-6 months. Until I finally fed the last couple adults to my mantids.  I was cleaning out their enclosure and instead of throwing the ooths out with the eco-earth substrate...I threw them in a plastic cup. Paranoid I guess.  3 days later...I've got red runner nymphs!  No idea why.  Other than being on the bottom of straight plastic (no substrate), the only difference is they weren't over a heating pad.  So maybe they just needed cooler temps?  Maybe they were being cannibalized by the adults? No idea.  But now my roach production worries seem to be at an end for now!  (mostly thanks to ausar318 - definitely a roach expert). 

Thanks for responding Arista...   ?