# N. Levis Incubation temp vs. sex



## Glider (Aug 10, 2007)

Hi guys, 

Well my gecko season started again last night with my first egg uncovered and in the incubator. Yay!

I have a question for the more experienced N. Levis breeders- Do you change the incubation temps to manipulate the sex of the hatchlings? 

Last year I incubated at around 28º, and ended up with all males. Quite possibly coincidence, as I only had a few eggs and my female only ever laid one egg at a time, but I wouldnt mind investigating incubation temp changes. 

I know that Ari has a lot of success with producing female clutches, and was wondering if anyone else was using temp to control (well not 'control', lets say 'nudge') the eggs into developing into a certain sex?

Anyone willing to share their techniques or experience?


Cheers


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## Saz (Aug 10, 2007)

I've incubated Nephrurus between 26 and 29 and have found pretty much a 50:50 split


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## MrSpike (Aug 10, 2007)

I bought 2 pair of geckos from Saz last season, each pair which where clutch mates turned out to be m/f.

Kane


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## Saz (Aug 10, 2007)

That's good news Kane. The three I kept for myself turned out to be 1 male 2 females.


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## ari (Aug 10, 2007)

Last season I had 24 Pilbarensis hatch out with the following ratio 4.20 - I think temps have alot to do with it.


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## Sdaji (Aug 10, 2007)

I know a couple of people who have hatched about 85-90% females at 34.5 degrees. I think it has just been coincidence, but they're adamant. It'll be interesting to see how they go this season.


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## junglepython2 (Aug 10, 2007)

Any deformities at those temps?


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## JasonL (Aug 10, 2007)

I incubate at 31 - 32 and get a high amount of females probably around 4/1, it wouldn't suprise me if they were similar to some dragons, low and high temps = females, mid temps = males.


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## Sdaji (Aug 11, 2007)

junglepython2 said:


> Any deformities at those temps?



Not that I know of, but it wouldn't surprise me. I certainly wouldn't recommend incubating them that high and at this stage my guess is that temperature doesn't affect the sexes. I incubated a few clutches of levis levis at 31.5 last season and had a reasonable male bias, I incubated levis occidentalis at the same temperature (in the same incubator) and had a strong female bias. I'm guessing it was purely due to chance. From my own experience (only one season of breeding them) and talking to other levis breeders, it seems that if there is any temperature affect you need to go pretty extreme to get any result.


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## reptyle (Aug 11, 2007)

great thread everyone.
I was under the impression that temp didnt play much of a role in sex determination of levis. Once a few breeders experiment a bit with temps, it will be interesting to see the outcome.

cheers, ian


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## hornet (Aug 11, 2007)

would incubation temp affect tawny dragon sex ratios?


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## Magpie (Aug 11, 2007)

I don't know if incubation temps make a diference, but something does. Maybe it's the males? Some breeders churn out a very high proportion of males and some of females and some get a 50/50 split.


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## Sdaji (Aug 11, 2007)

Magpie said:


> I don't know if incubation temps make a diference, but something does. Maybe it's the males? Some breeders churn out a very high proportion of males and some of females and some get a 50/50 split.



I know one or two who seem to produce all males... although their "unsexed babies" are already clearly males when they go to their new homes...

Random events are more random than people seem to expect (if anyone is up for a bit of torture, do a stats course; it's as interesting as it is painful). If you flip a coin ten times you'll likely get 80% heads and 20% tails, or the other way around, etc etc. If you flip a coin 1,000 times, you'll get close to 50:50. Until you've produced a few hundred under the same conditions, it's difficult to say whether something is affecting the sex ratio or you're just looking at the whimsical nature of chance. Random sequences and ratios rarely appear to be random.


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## Magpie (Aug 11, 2007)

Sdaji said:


> I know one or two who seem to produce all males... although their "unsexed babies" are already clearly males when they go to their new homes...
> 
> Random events are more random than people seem to expect (if anyone is up for a bit of torture, do a stats course; it's as interesting as it is painful). If you flip a coin ten times you'll likely get 80% heads and 20% tails, or the other way around, etc etc. If you flip a coin 1,000 times, you'll get close to 50:50. Until you've produced a few hundred under the same conditions, it's difficult to say whether something is affecting the sex ratio or you're just looking at the whimsical nature of chance. Random sequences and ratios rarely appear to be random.


 
I'm resonably cluey about stats, people never believe you when you tell them that 1,2,3,4,5+6 have the same odds of coming up in lotto as any other 6 numbers 
But some breeders seem to produce consistent males or females year after year.


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## grimbeny (Aug 11, 2007)

lol I'm doing stats at the moment, our lecturer put this cartoon up just to highlight this point.

http://da.nieltiggemann.de/science/rng/dilbert.png

most of u probably wont find it funny but i did


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## Reptilian (Aug 11, 2007)

I dont know about geckoes, dragons and snakes, but i do know that crocodile incubation temps greatly affect sex of the offspring...

Regards...
Ash...


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## JasonL (Aug 11, 2007)

Magpie said:


> I'm resonably cluey about stats, people never believe you when you tell them that 1,2,3,4,5+6 have the same odds of coming up in lotto as any other 6 numbers
> But some breeders seem to produce consistent males or females year after year.



Yeh, I don't play lotto because of stat's, but there are still those lucky #####"s that win it twice! I agree there is something going on, either genes or temps? But we still have so much to learn, that's why this hobby is so interesting I guess.


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## JasonL (Aug 11, 2007)

hornet said:


> would incubation temp affect tawny dragon sex ratios?



Some how, it probably would. Peter Harlow found that it effects water dragons, but not CBD's. Some recent work by other's recorded it does effect CBD's when incubated at very high temps. So much work need's to be done.


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