This happened ~18 months ago. I have been maintaining a colony of dubia roaches for many years now. Started with a couple packs from PetsMart (they carry them now) back in ~2018, I only had 1 tarantula so I did not need many but it was more convenient to just keep them alive and growing than to have to go find feeders and deal with crickets.
From a starter of about ~50 PetsMart babies, it was super easy to raise them up in a spare 2.5g critter keeper tank (tall walls to keep them from climbing out), I just fed them plain breakfast cereal supplemented with dry oatmeal and a handful of dog food, plus water gel. They grew to adults and made plenty of babies for years.
Over the years I had done smaller culls, of roughly ~20-30% of the total colony, which numbered around ~200-300 roaches of all mixed sizes. Never had an issue with this and the colony just kept going and making more babies.
So about 18 months back due to life situations I decided to do a big reset on the colony and did a ~90% cull. I kept roughly 20 adults (more females than males), and maybe ~50 babies & juvies.
I am not entirely sure what went wrong after this but its been downhill ever since. Last spring we went away for a week and I think the temperatures in the house fluctuated unexpectedly due to weather outside (there was a brief hot flash followed by a cold snap while we were gone) and I returned to find ALL of the juvies and babies dead. I was not too worried since I still had all my adults, and my tarantulas (I acquired a second) did not need much to eat. Well over the course of the year, NONE of my adult females had any babies. I could see my remaining sub-adults all maturing one by one, the females were all getting fat and well fed, the males are doing their thing with them all in the evenings (have caught them in the act several times), all my husbandry is exactly the same as its always been in the prior ~5 years. But no babies. Worse, my adults started dying. Pretty sure just old age, since many of them were adults when I did the cull and at this point it had been +12 months since then, so an adult at cull-time would have been ~24-36 months old at this point which I think is about their natural lifespan.
The tarantulas did eventually need to eat so I fed off only adult males, until now I have literally only TWO adult males left (several more also died on their own). A couple adult females died over the same time period. I have about 8 adult females left, and they have all been adults for ~6-12 months. And no babies. I did find at least two ootheca ejected in the tank litter. So something is going on, but I dont really know what.
I finally decided to throw in the towel and went back to PetsMart and grabbed a batch of ~20 babies to start things over again with. But its gonna take them ~6 months to mature. Not sure if they will grow fast enough to feed juvies to the T's instead of the remaining females.
Any ideas on what happened here? Its not even my first time keeping roaches, I had a colony of Discoids for years prior in the past we well. Never had issues like this. Do colonies just collapse? Maybe my bloodline became infertile? Gonna have to keep a much closer eye on them from now on but I honestly am not even sure what to do differently.
From a starter of about ~50 PetsMart babies, it was super easy to raise them up in a spare 2.5g critter keeper tank (tall walls to keep them from climbing out), I just fed them plain breakfast cereal supplemented with dry oatmeal and a handful of dog food, plus water gel. They grew to adults and made plenty of babies for years.
Over the years I had done smaller culls, of roughly ~20-30% of the total colony, which numbered around ~200-300 roaches of all mixed sizes. Never had an issue with this and the colony just kept going and making more babies.
So about 18 months back due to life situations I decided to do a big reset on the colony and did a ~90% cull. I kept roughly 20 adults (more females than males), and maybe ~50 babies & juvies.
I am not entirely sure what went wrong after this but its been downhill ever since. Last spring we went away for a week and I think the temperatures in the house fluctuated unexpectedly due to weather outside (there was a brief hot flash followed by a cold snap while we were gone) and I returned to find ALL of the juvies and babies dead. I was not too worried since I still had all my adults, and my tarantulas (I acquired a second) did not need much to eat. Well over the course of the year, NONE of my adult females had any babies. I could see my remaining sub-adults all maturing one by one, the females were all getting fat and well fed, the males are doing their thing with them all in the evenings (have caught them in the act several times), all my husbandry is exactly the same as its always been in the prior ~5 years. But no babies. Worse, my adults started dying. Pretty sure just old age, since many of them were adults when I did the cull and at this point it had been +12 months since then, so an adult at cull-time would have been ~24-36 months old at this point which I think is about their natural lifespan.
The tarantulas did eventually need to eat so I fed off only adult males, until now I have literally only TWO adult males left (several more also died on their own). A couple adult females died over the same time period. I have about 8 adult females left, and they have all been adults for ~6-12 months. And no babies. I did find at least two ootheca ejected in the tank litter. So something is going on, but I dont really know what.
I finally decided to throw in the towel and went back to PetsMart and grabbed a batch of ~20 babies to start things over again with. But its gonna take them ~6 months to mature. Not sure if they will grow fast enough to feed juvies to the T's instead of the remaining females.
Any ideas on what happened here? Its not even my first time keeping roaches, I had a colony of Discoids for years prior in the past we well. Never had issues like this. Do colonies just collapse? Maybe my bloodline became infertile? Gonna have to keep a much closer eye on them from now on but I honestly am not even sure what to do differently.
Culling 90% of your colony drastically reduced genetic diversity and population resilience. They are hardy, but such a severe reduction can create a bottleneck, especially if the remaining individuals weren’t the healthiest or most reproductively viable. The small number of adults (20, with more females than males) and 50 juveniles might not have been enough to sustain a robust breeding population, particularly if some of those adults were already nearing the end of their reproductive lifespan.
