Questions about dubia colony

[Deacon]

I just cleaned my small dubia colony. I read that you shouldn't have too many adult males as they fight and disrupt the females. I have about 200 roaches total (100 sub-adult and adult, and 100 purchased nymphs 3/4" and under.)

So I counted the adult males as I moved them---43 adults, now 37 as I gave six to a friend with a bearded dragon. That means that at least half of the original purchase of 100 nymphs is male and more are molting each day.

1- So maybe I have 50 adult or sub-adult females, how many males should I keep?

2- Anyone know how to tell if a female is carrying an ooth? I read that they lay the eggs and retract them into their body for about a month. That time has come and gone and there were no tiny nymphs when I cleaned the bin. But, some of the females looked really fat. Is that the way to tell who has eggs in the oven?

I'm just raising these dubias until my mantid nymphs grow up. Yesterday, I cut a small roach in half and tried to coax my L7 Hierodula membranacea to taste it but she refused repeatedly. So, I put a dab of honey on it which she ate and then backed away. Wasted a roach.

Anyway, if someone who raises dubias could answer my questions, I would appreciate it.

Thanks.

 

[Salmonsaladsandwich]

A 3:1- 7:1 ratio is supposed to be ideal, although I'm not sure how whoever came up with that got those numbers. Since the colony is small I wouldn't get rid of too many males to maintain genetic diversity.

I can tell you for sure that it's very hard to tell whether a female is carrying an ooth. When she sticks it out, after she pulls it back in she looks normal- not particularly fat. She starts to get fat a few weeks later when the babies are almost ready to be born. However just because she's fat doesn't mean she's pregnant, she could just have easily eaten a large quantity of moisture laden food. One day few or none seem to be pregnant, the next you feed them some leftover watermelon and suddenly they're all pregnant!

Wait till you start getting adult males. They're much more active and easier to grasp than nymphs. But nevertheless dubias seem to be one of the worst feeders for mantids, they just don't attract attention.

 

[Deacon]

Wait! I thought mantids loved these roaches! And I thought they were a good one to raise since they don't climb. (I can handle an escaped fly but I'd be in deep trouble if I "lost" a roach!) I don't mind handing my mantids food (whole or all mixed up) with tweezers or putting the mantid in a cup with the roach. But so far, I haven't had any takers. I got them for my Chinese mantids but they wouldn't eat them whole or in pieces. Now, I really only have one nymph big enough to try a piece (she's still smaller than an adult male dubia) and she just turns and runs. Hopefully, that won't always be the case or I'll need more acquaintances with big lizards!

I do have adult dubias. When I changed their bin out, those males were quick as the devil! I took them out first so I could get a count---a lot of them were caught by the tips of their wings as they were fleeing to the other side of the egg crates! The females (I didn't count them) were slow and unaffected by all the disturbance. I can see someone having a female for a pet.

Okay, I'll take your advice and leave the population alone for a generation---too bad watermelon is out of season! Thanks for your input!

 

[Salmonsaladsandwich]

Well, mantids love them once they catch and start eating them. The problem is getting them to try. My adult Chinese mantids eat them but it can takes days, sometimes I just turn the cage upside down to disturb the roach and bring it into conflict with the mantis.

I'm sorry the thing about the watermelon was confusing. I was being sarcastic, what I meant was that a heavily pregnant roach is fat, but can't be told apart from a roach that has engorged itself with watery food like watermelon. Watermelon won't actually make all your roaches pregnant overnight, but it will make them all fat so they look pregnant. The best thing to feed them for increased reproduction is oranges.

 

[Deacon]

Salmonsaladsandwich,

Okay, I'll add turning over the cage to my growing list of how to persuade a mantid to eat a boring roach. I got the sarcasm but my tongue-in-cheek mustamissedamark :stuart: And, I did not for a minute think you actually meant watermelon would make them pregnant. Everybody knows that's pumpkin!

Thanks for your post!

 

[Salmonsaladsandwich]

Lol, I'm the stupid one who didn't get it.

 

[Deacon]

Just having a little fun with you and I always enjoy your responses. Thanks for the help.

 

[Krissim Klaw]

I've always thought dubia where on the large side for mantises, however I know I've seen a number of members mentioning how much they like them. Do you guys feed the nymphs typically then or will the larger mantises also handle the adults? I've been using roaches for about a year now, but I went with P. nivea for the smaller, lighter build. Funny you should mention watermellon because I got a fairly meh reaction out of my colony when I offered that. They did eat it but that was after going through the rest of their veggies/fruit.

One method I've found that works well for less active prey like roaches is to get something like a little white dixi cup. You can trim it so there isn't much of a rim then plop the roach in and hold it so the mantis can see down on the prey. The roach will stand out from the white and often if you just rock the cup slightly and they will immediatly lock in on the roach and go into hunting mode.

 

[Salmonsaladsandwich]

Yes, I agree that green banana roaches are much better feeders for mantids. For those that are big enough, the adult male dubias are most readily accepted due to being more active and easier to grab but few species can handle them. If I was getting feeders specifically for my mantids I would've gone with a different species but the dubias are mostly for my amphibians.