Pregnant molly?

Genessee

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So when i got my 2 black mollies they were both pregnant. My single male molly died before they gave birth. Sadly none of the babies made it, and one of my mollies looks pregnant again. Is it possible for them to hold sperm while pregnant, or is it more likely one of my male guppies got her pregnant?
 

Colin_T

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guppies and mollies don't hybridise.

common female livebearers can carry up to 6 sperm packets and use them when they want. your female is gravid (pregnant) to a male molly that she bred with some time in the past.
 

TMAllen

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guppies and mollies don't hybridise.

common female livebearers can carry up to 6 sperm packets and use them when they want. your female is gravid (pregnant) to a male molly that she bred with some time in the past.
I read something not long ago that indicated that the two, guppies and mollies do interbread but that the offspring are sterile. The citation is here: "Freshwater Aquariums," Thraves, Hiscock, Sandford, Interpet Publishing, 2007. I've also heard, anecdotally, that the same happens with platys. If you think about it, and, please understand that I'm not an evolutionary zoologist, these livebearers are older than their egg laying cousins. Livebearers date back to the Coelicanth. If the physiological structure works and the species involved are all on the same evolutionary branch, well, it's not impossible. I am a bit of a skeptic and even if I read it in something peer reviewed, I still retain judgment. But, somewhere, if there was any merit to what was written in this book, there is a sterile molly/guppy out there. I don't have the exact pages now, but it seems to me that the guppy or molly needed to not have any options for their own - that is, this took place, most likely, in a lab somewhere where the females were separated from the males of their particular types but 'survival of the specie' was so strong, that it created a sterile offspring.
 

emeraldking

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Most (so, not all) ovoviviparous livebearer females are able to store sperm packets in the folds of their fallopian tube for over year even. Mollies and guppies belong to this group.
Can mollies crossbreed with guppies? Yes, they can. But if both genders of both species are in one tank, the females prefer males of their own kind as a mating partner despite of the long chasing behavior of the males of the other species. Would you keep only the opposite sex of of both species in one tank, it's more likely that a female gives in to let a male of the other species mate with her. Hybrids between these two species "can" be less fertile till even sterile.
Even the phenotype of a cross between a molly and guppy differ. For that depends on the phenotypes of both species used. Mollies and guppies can mate because their sexual organs are compatible. So, it's not specifically that they share the same genus. The lower fertility and infertility has got more to do with how close or how far both species are related.
Here's a link: http://emeraldking-aquatics.com/livebearer6.
A good example that sharing the same genus isn't evidence of actual offspring, is shown in the comma swordtail (Xiphophorus signum). These won't crossbreed with othe swordtails or platies. Their reproduction system is different from the others. But yes, most related species where the sexual organs are compatible with another, can establish offspring (fertile, less fertile till sterile).
 

TMAllen

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Most (so, not all) ovoviviparous livebearer females are able to store sperm packets in the folds of their fallopian tube for over year even. Mollies and guppies belong to this group.
Can mollies crossbreed with guppies? Yes, they can. But if both genders of both species are in one tank, the females prefer males of their own kind as a mating partner despite of the long chasing behavior of the males of the other species. Would you keep only the opposite sex of of both species in one tank, it's more likely that a female gives in to let a male of the other species mate with her. Hybrids between these two species "can" be less fertile till even sterile.
Even the phenotype of a cross between a molly and guppy differ. For that depends on the phenotypes of both species used. Mollies and guppies can mate because their sexual organs are compatible. So, it's not specifically that they share the same genus. The lower fertility and infertility has got more to do with how close or how far both species are related.
Here's a link: http://emeraldking-aquatics.com/livebearer6.
A good example that sharing the same genus isn't evidence of actual offspring, is shown in the comma swordtail (Xiphophorus signum). These won't crossbreed with othe swordtails or platies. Their reproduction system is different from the others. But yes, most related species where the sexual organs are compatible with another, can establish offspring (fertile, less fertile till sterile).
I believe that this is what I was saying. The only way you can know with livebearers is to keep a fry alone until maturity. Right now, I have two female guppy fry, both nearing 3 months, the two brothers died two months ago, and one of the females looks pregnant. If the fish have no other options, the drive to keep the fish line going is so strong that they might cross-breed - actually they have - but their offspring are sterile.
 
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