Rothschildia cincta - only males emerge!

[Fernando]

Hi!

Well, I brought some R. cincta ssp gerreronis ova from Mexico, and I reared them with no problems. They span their cocoons and they are now starting to hatch, but there's some strange about it: 9 out of ~25 adults have emerged so far, and everyone of them is a male!

Is that common? Never happened to me before with any other species. I mean, what are the odds of that happening? Asumming there's a 1 to 2 chance of getting a male, it would be 1 to 2⁹ --> 1 to 512.

Of course, there could be another factor involved. Maybe males emerge sooner than females?

[bobw]

Certainly in butterflies the males always emerge well before the females. This is because they need a few days to feed up before they're ready to pair; I assume the same applies to moths that feed. However, as they don't feed I don't see why it should apply to Saturniids, especially as males are usually only any good for pairing for about two or three days before they become too weak. In my experience they usually emerge at about the same time, or maybe the males are one day earlier.

Wait and see what happens. Maybe it will even up or maybe you have one of those unusual occurrences where a brood is all one sex. This was discussed in a recent thread on sex ratios.

Bob

[Deleted]

With the saturniids I've reared, often some males will come out a few days prior to females. I suspect that these few days would best enable the male to be "on-the-wing" for when the female sends out her pheromones and he must fly to seek her out. After a few days, both sexes are emerging equally.

[Fernando]

I see, thanks for the answers.

Anyway, I already put the fresher males in the fridge, just in case females -if there are any haha- take too long to emerge.

Thanks again!

[evra]

I haven't reared that particular subspecies of cincta, but yes, the males tend to emerge 1-2 weeks before the females in my experience for the most part. There are always some early flying females and late flying males though. Also, when I put the males in the refrigerator it actually killed them.

[Fernando]

I have put E. calleta males in the refrigerator for several days and they've survived. Is R. cincta less "cold resistant"?

[evra]

The short answer is yes, they can't take cold like a lot of other saturniids. It may have something to do with my refrigerator temperature though, which was set at about 3 degrees celsius at the time. Normally E. calleta, H. c. gloveri, Agapema anona, Automeris iris, etc can handle that cold of a temperature, but it's risky with R. cincta and Citheronia splendens in my experience.

[Fernando]

I see, thanks for the answer!

By the way, the first female Rothschildia just emerged hehe