Reptile & Amphibian Forums

In Mark Bayless new book he mentions lone female monitors producing viable eggs. Bernd Eidenmuller was the source of the data.

We are currently incubating an apparently fertile egg from a female Varanus salvator that has been isolated from her species for over three years.

Bernd or Mark monitoring this forum? Please contact me. If anyone is a mutual friend, please put us in touch with each other.

Thanks!
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AMAZON REPTILE CENTER

NAMED BEST REPTILE STORE IN LOS ANGELES

i believe Mark Bayless has been banned from this forum. he frequents varanus.nl

or you can contact me with your e-mail address and i'd be happy to pass it along to him.

cheers
shay

Could you post the citation in the book so I can look up the original paper describing facultative parthenogenesis in Varanids? I haven't heard of any instances of this before and it sounds quite interesting. Basically I would like to know the Journal Name and Volume number, Article Title, and year of publication of the original article that Bayless references (I think you said Eidenmuller authored it?)
Thanks!

P. Lenk, B. Eidenmueller, R. Wicker, M. Wink. 2005. A parthenogenetic Varanus. Amphibia-Reptilia 26:507-514

Thanks!
Just finished reading the paper, it seems very interesting. However, the species they describe facultative parthenogenesis in (V. panoptes, Argus Monitor) is relatively easy to find in the US, I wonder why there have not been more instances of parthenogenesis being recorded. They describe having two females, both of whom produced eggs despite never being in contact with a male (though only one of the eggs was successfully incubated). It seems that if both of their females produced eggs while being kept singly, there would be at least a few examples of herpetoculturalists who kept single female Argus and at least had eggs laid, even if they weren't incubated to hatching.
Another question this raises to me is if other species of Varanid can also reproduce via facultative parthenogenesis. Within the same subgenus and in other subgenera of Varanids.

Do you mean "viable" eggs? Monitors lay infertile eggs whether with a male or not. I'm assuming this is what you meant, but you mentioned it twice.

Oh, i forgot, I incubated two clutches for practice and for the 1 in a million chance of parthenogenesis occurring with my Argus female in the past. She began clutching at one year old almost monthly, so i got a male. The infertiles all decomposed after about one week. They are more translucent even after they begin to dry vs. fertile eggs.

>>Could you post the citation in the book so I can look up the original paper describing facultative parthenogenesis in Varanids? I haven't heard of any instances of this before and it sounds quite interesting. Basically I would like to know the Journal Name and Volume number, Article Title, and year of publication of the original article that Bayless references (I think you said Eidenmuller authored it?)
>>Thanks!

Bayless offers none.
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AMAZON REPTILE CENTER

NAMED BEST REPTILE STORE IN LOS ANGELES

There have been a few cases that I have heard of, but with the exception of Bernie's they are all circumstantial; females laying viable eggs without a male present, or in the company of a male of a very different species. I suspect that if one species can do it they all can, although the circumstances under which it happens are unclear- it is a very rare phenomenon. Just be grateful that women can't do it...... yet!!
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Mampam Conservation

is a very rare phenomenon. Just be grateful that women can't do it...... yet!!

There is no evidence whatsoever that it does not happen in human females.

A) it can happen amongst the population of women having sex so we'd never even find it

B) the ONLY population of women this could be noticed and therefore documented would not believed if she came forward.

Any virgin nuns that have given birth should step forward and have the DNA of her children tested.

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AMAZON REPTILE CENTER

NAMED BEST REPTILE STORE IN LOS ANGELES

We have been breeding both Argus and Water monitors at our store since 1998. We have produced well over 50 argus monitors and about 25 water monitors.
We have had our water monitor females lay up to 13 infertile eggs without being in the presence of a male for over 6 months. In total we have had about 50 eggs go unfertilized since we started this breeding. Some of these eggs are laid and appear to be completely fertile, some of those weighing more than eggs that actually hatched. We give them time to incubate (sometimes as long as 3 months after oviposition), but they have gone bad every time. I would also like to point out that our youngest female just laid 3 eggs about a month ago. She had never been caged with any other animals, period. Those eggs were certainly not fertile.
Our argus monitors are not much different. Most of the time we don't even try to determine sex other than waiting until the monitor lays infertile eggs or breeds with one of our females. We have had at least 50 infertile argus eggs, due to bad timing on placement of the males and females together. None of these eggs have ever hatched, and only about 4 could have passed as fertile immediately after oviposition.
We have never heard of any monitors laying fertile eggs without the presence of a male and strongly believe that such an event could be more likely blamed on error of the breeder, than asexual reproduction.
I'm not even gonna talk about human asexuality.

What are you asking? Is this "known" to science with varanids? Not really, but not much is known about varanid reproductive biology. (aside from that single paper)

Are you wondering if you should continue to incubate the eggs? If your interested in the results, then yes, do incubate them.

If your wondering if non-parthnogentic reptiles can at times practice single sex reproduction, the answer is yes, look up some of Dr. Gordon Shuetts work on this subject. He proved throught DNA work, that many instances that were thought to be sperm storage were not, but were indeed parthnogenic reproduction. With such species as kingsnakes, rattlesnakes, some other lizard types etc.

If you research sperm storage in varanids, you may find some events have been recorded. The question is, were they sperm storage or parthnogenisis? I believe, no proof (DNA) has been done on longterm sperm storage. These events may be parthno. as well.

In my expereince, unbred monitors commonly lay infertile eggs. But on many occasions, we have recieved fertitle eggs as well. In the past, I do not recollect hatching this fertile appearing eggs. But at this time, I have some near hatching. A common result of clutches from non bred females is, a few fertile appearing eggs, and the rest normal infertiles. Again the problem is, you have to know the difference. I think in most cases, keepers think the eggs are bad(no male) and discard them.

Now to the state of varanid keeping, most keepers do not know the difference between an infertile egg and a fertile eggs. They also do not understand the difference between a dead fertile egg and a living fertile eggs. With this in mind, gathering evidence to indicate parthnogenic reproduction would be difficult. As the keepers do not understand the basics. This includes academics.

If you have some eggs from a single sex reproductive event, then by all means contact Dr. Shuett, as he has had this type of work done. So he may be able to give you a lab experienced with this kind of work. Cheers

>> If you have some eggs from a single sex reproductive event, then by all means contact Dr. Shuett, as he has had this type of work done. So he may be able to give you a lab experienced with this kind of work. Cheers

Thanks Frank. It will be interesting to hear the results of your possibly parthenogenic eggs.

I definitely knew it had been documented in monitors and Harold helped with the reference. I am well aware this phenomena is actually pretty common in reptiles.

This is probably evolution's response to allow colonization. Animal finds herself in new yet productive territory. Evolution allows her to reproduce and start a whole new population.
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AMAZON REPTILE CENTER

NAMED BEST REPTILE STORE IN LOS ANGELES

So this animal is producing clones of herself? Like the burmese i read about in the Reptiles Magazine. Where i'm starting to get confused is how the words "pretty common" are getting mixed in. I know there are a few species that are completely parthenogenetic, is that what's being referred to? Or are we now saying that it is pretty common in all reptiles? How many instances have been documented by people we can trust? As far as kingsnakes, how come i havn't heard of this before, and why did they make such a big deal about that burmese if this type of reproduction is pretty common?

When the monitor reproduces in this manner, are all of the hatchlings females? Will they be more likely to reproduce in the same manner? It would certainly not be effective if a female tries to colonize in any other way, being that it's not a good idea to have siblings inbreeding, let alone siblings with identical DNA.

My biggest problem with this idea is that it seems extremely rare and should not be considered a regular occuring in monitors. I find it HIGHLY unlikely that any eggs currently incubating without a male ever copulating with the female will hatch. I would definately like to hear your results.

Last, does anyone else believe that monitors are born without sex and that dominant cagemates will become males and the others will become females? This is all information that I have never read in any books and would like to know where it's coming from. Thank you all for your input and time, I find this to be very interesting.

I guess at this time there is no practical use for promoting snakes to produce parthenogenically. At this time the interest in producing snakes as well as other reptiles is to make them, different, not make replicas of the female.

I had this happen many times in the late sixties and early seventies. I tried to publish it in the mid seventies. I was actually with a research grant and with a experienced publisher. It was denied because no one else had ever heard of such a thing.

But not its commonplace with snakes.

As I mentioned above, it the PR(partheno reproduction) was confused with sperm storage. There have been lots and lots of instances of persumed sperm storage. The problem was, its was never proven. That is, the offspring were never subject to DNA testing. Then along came Dr. Shuett, he was working with DNA work on crots. So to test this was inline with his experience.

If I remember correctly, he found two types of PR, diploid and triploid. One type produced all male offspring. Which was my experience at the time. Consider, I did not read his papers(no reason too) He told me in person on a field trip.

The point here is twofold, one, there is little interest in this and two, It(PR) has not been induced on a regular basis. It occurs sometimes, and not at others. The reason/s are not understood what causes it to happen. Cheers

Thouhgt i would answer your questions directly.

> So this animal is producing clones of herself? Like the burmese i read about in the Reptiles Magazine. Where i'm starting to get confused is how the words "pretty common" are getting mixed in.

we here about it every year. must happen more than we here.
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> I know there are a few species that are completely parthenogenetic, is that what's being referred to? Or are we now saying that it is pretty common in all reptiles?

or... sumthing inbetween?
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> How many instances have been documented by people we can trust?

FR refers to schutt for these details. Ill go read them, will you? Man, I cant spell but I can read.
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> As far as kingsnakes, how come i havn't heard of this before,

are you the clearing house for kingsnake breding data? Just curious why you feel you must know all that is know bout kingsnakes?

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> and why did they make such a big deal about that burmese if this type of reproduction is pretty common?

cuz it was a big deal. burmz are big snakes.
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> When the monitor reproduces in this manner, are all of the hatchlings females?

???? ask Bernd Idenmuller, he did a study.
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Will they be more likely to reproduce in the same manner?

??? sorry I dout anyone can anser this one.
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> It would certainly not be effective if a female tries to colonize in any other way, being that it's not a good idea to have siblings inbreeding, let alone siblings with identical DNA.

why is this bad? Are you a geneticist? I thought you were a geologist. Your name is stoned.
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> My biggest problem with this idea is that it seems extremely rare and should not be considered a regular occuring in monitors.

OK. But really who cars either way?
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> I find it HIGHLY unlikely that any eggs currently incubating without a male ever copulating with the female will hatch. I would definately like to hear your results.

Thanks for the opinion. fortnatly FR feels diffrent.
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> Last, does anyone else believe that monitors are born without sex and that dominant cagemates will become males and the others will become females?

reads this one:

http://forums.kingsnake.com/view.php?id=1168372,1168442
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> This is all information that I have never read in any books and would like to know where it's coming from.

why do you feel books are the only source of info? Scientist making good discoverys write for jurnals and mostly not books. Read these like the one by idenmuller and you'll have lotsa new knowledge not found in books.
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> Thank you all for your input and time, I find this to be very interesting.

backatcha

You did an excellent job of breaking me down. You were very helpful in my quest for knowledge.

Here is an article I believe FR was referring to...

http://home.pcisys.net/~dlblanc/articles/Parthenogenesis.php

Now, I do have an abberant patterned eastern kingsnake that hatched this summer that is likely the product of parthenogensis. The mother has not physically been with a male for 7 years (possibly longer). She did lay a viable clutch this year. 10 eggs were laid, 6 were good, but ultimately only 1 made it to hatching (female).
.

.

.

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PHWyvern

Thanks for the link. This only explained the diploid PR. In person, he also told me of a triploid PR that allowed for females to be reproduced. Thanks again.