Is this statement True???

[johnnyboy4783]

Sex in leopard geckos is determined within the first 2-weeks of incubation. So if you let albino eggs experience 78-83F for 14-20 days (20 days is better to place it safe) that will lock in the female sex and then you merely move those female eggs to a constant 90F for the remainder of incubation to get the best looking possible female offspring.

 

[Golden Gate Geckos]

Actually, it's more like the first 3 weeks of incubation for the gender to be determined. Many breeders choose this method of incubation in order to produce brighter colored geckos, especially albino morphs.

 

[Baysidegeckos]

Yes it said to be the first 28 days of the incubation will detirmine the sex at what ever temp you have it at.
But i always give my albino females a month in the cool incubator at 83F then after that month i put them in the male incubator which is 90F for the remainder of the time until they hatch, to get brightly colored albino females.

 

[ataber]

bret do you do the same with your carrot tails?

 

[malt_geckos]

Yeah, I like Brets idea.

But if you're not careful, the females will be "hot" and may act like a male or be infertile.

 

[Baysidegeckos]

Yes, i do it with all my eggs, but the temp on the CT doesnt do anything, it only does it with albinos.

 

[Surf_420]

i swear i have the hottest female in North America.

Mango, she does not like being held, touched, or even talked to.

Everytime you get near the enclosure you scats across it like a drag car.

i did ask the breeder of her what the temp she was incubated at and my

thoughts were right and she turned out to be incubated at a higher temp.

Was supposed to be incubated for male but ended up female.

 

[Golden Gate Geckos]

Once again, I would like to state that there is no scientific evidence to prove that females incubated at higher temperatures are "hot". Back in the 80's, Dr. David Crews conducted a study with females incubated at high temperatures, and it was believed that they were sterile and more aggressive towards males, thus the term 'hot female'.

It turned out that he was not keeping those females long enough, because 10 years later Drs. Viets and Tousignant found that females incubated at higher temperatures reached sexual maturity and ovulated about a year late than most other females. Once they were ready to breed, the aggression towards the males disappeared.

I believe that a gecko's disposition is partly an individual thing, and partly genetic. Awhile back, practically ALL blizzards had nasty dispositions, I also have a reverse stripe female (not incubated at higher temps.) who was downright mean for the first year of her life, and literally every single one of her offspring was aggressive. Although I do not have any statistical evidence, in the 13 years I have been working with leopard geckos I have found in many cases that gentle, sweet-natured geckos produce gentle, sweet natured offspring... and skittish, aggressive geckos produce skittish and aggressive offspring.

 

[yellermelon]

Thats good food for thought Marcia, thanks for sharing.

 

[robin]

can we perhaps discuss the possible problems related with switching temps after locking in the sex?

 

[preacherman]

Good post, Marcia. Perhaps we should be paying more attention to disposition when chosing potential breeders. It's easy to become completely focused on new mutations and brighter colors and forget about the fact that many people choose to keep leopard geckos because they want a reptile that they can interact with. Selectively breeding for disposition can only help to make these animals more popular.
And I'm with Robin, I'd like to hear from breeders who have extensive experience with the incubation technique being discussed. It seems to me that there would be a lot of potential for deformities with such a sudden and drastic change in incubation temps. I've never seen the need to switch the temps on females, as the females that we've produced at 82-83 degrees look every bit as good as the males incubated at 88. Our Tremper Sunglows that came out of our female incubator this year looked better than those that came out of our male incubator.

 

[johnnyboy4783]

I have also read about what marcia was saying. There is now prrof that higher incubation temps will cause a hot female.

 

[johnnyboy4783]

one thing i did question when i first came to this site was breeding offspring vack to parents and all that. No one think this could cause problems due to inbreeding? I know in dogs this can cause the pups to have behavior problems.

 

[Golden Gate Geckos]

There is now prrof that higher incubation temps will cause a hot female.

Can you please provide us with the source of that 'proof'?

 

[johnnyboy4783]

sorry bout that but i didnt mean now i meant i found some proof but it is from 1988 still researching for newer stuff.
http://query.nytimes.com/gst/fullpa...3A25756C0A96E948260&sec=&spon=&pagewanted=all

If i find anything newer i will post it!

 

[Golden Gate Geckos]

It's great that you are doing your research! The study from 1988 is from Dr. David Crews. There is a newer study by Dr. Brian Viets in 1993, and an even newer one by Dr. Tousignant in 1995, that proved the earlier study by Dr. Crews was not correct. This is why I posted this earlier in this thread:

Once again, I would like to state that there is no scientific evidence to prove that females incubated at higher temperatures are "hot". Back in the 80's, Dr. David Crews conducted a study with females incubated at high temperatures, and it was believed that they were sterile and more aggressive towards males, thus the term 'hot female'.

It turned out that he was not keeping those females long enough, because 10 years later Drs. Viets and Tousignant found that females incubated at higher temperatures reached sexual maturity and ovulated about a year late than most other females. Once they were ready to breed, the aggression towards the males disappeared.

 

[SteveB]

I'm going to disagree, Marcia. Look at the studies referenced the last time we had this discussion.

Hot females do exist. The fact is that they have altered hormone levels, they become sexually mature significantly later in life, and they do have behavioral traits that are different from that which a normal female exibits prior to reaching maturity. They are biologically, developmentally, and behaviorally different from normal females.

 

[Golden Gate Geckos]

I agree to a point, Steve. I agree that if the females incubated at higher temperatures develop sexually later than other females, that their hormones are probably affected for that specific element of development. What was disproved was that 'hot females' are aggressive by nature and sterile. This is simply not true.

 

[SteveB]

Check back on the last discussion we had. There was a proven difference in hormone levels in the more recent studies. I agree that "hot females" are not doomed to a lifetime of bitter isolation

Now I always give the example of my "hot female" blizzard who was from an early generation of blizzards that still had a reputation for nasty temperments. She was the sweetest gecko I ever owned. Horrible breeder, and had a feeding response so strong that she would try to attack the wagging tail of males attempting to court her, but extremely well tempered. And definitely fertile, despite not being very productive.

 

[Golden Gate Geckos]

We all know that not all females incubated a higher tempratures are sterile and are not all agressive, which is the general belief in association with 'hot females'. I think the original topic of this thread was in regard to the dual temperature incubation method, which would not apply since they are first incubated at lower temperatures for their gender to be determined. I brought up the most credible recent studies that disspelled this 'myth' in response to this post:

But if you're not careful, the females will be "hot" and may act like a male or be infertile.

One study comes to mind that actually implies that 'cool males' are more likely from TSD alteration than 'hot females':
http://endo.endojournals.org/cgi/con...ct/140/10/4501