Diapause Explained

[John Ramos]

Hi All,

This isn't my knowledge but there is a bunch of good solid knowledge on this system.

Have at it, tell us all about it, all the gory details!

John

 

[Moozillion]

I think diapause is when human women are past their reproductive years: they quit having menstrual periods, have hot flashes, get b*tchy and develop moustaches...

 

[Yvonne G]

LOL!

Diapause, when talking about hatching tortoise eggs, is a the delay in development in response to regularly and recurring periods of adverse environmental conditions. It's another mechanism - like hibernation/brumation is a mechanism - used as a means to survive predictable, unfavorable environmental conditions, such as temperature extremes, drought or reduced food availability.

So if one were to try to hatch eggs laid by one of these type tortoises, one would cool off the eggs for a period of time, then start them up again in the heated incubator.

 

[Yellow Turtle01]

Way more descriptive, Yvonne

 

[John Ramos]

LOL!

Diapause, when talking about hatching tortoise eggs, is a the delay in development in response to regularly and recurring periods of adverse environmental conditions. It's another mechanism - like hibernation/brumation is a mechanism - used as a means to survive predictable, unfavorable environmental conditions, such as temperature extremes, drought or reduced food availability.

So if one were to try to hatch eggs laid by one of these type tortoises, one would cool off the eggs for a period of time, then start them up again in the heated incubator.

Wow, that sounds like a can o' worms, not knowing how long they'd been there, I guess having to candle them, cooling them off for an indeterminate amount of time, incubate them and then get a funny smell, well, not so funny smell! Haha

And, if they do hatch, will they be males, females or hermaphrodites?

Brumation, reminds of when I brought a new broom for the kitchen, wif said what's this for, I said it's your new car! LOL She didn't think it was funny...

 

[Yvonne G]

Wait, do you have some eggs, John?

 

[John Ramos]

No, but my quest isn't over yet. Yvonne was talking about them, all the gory details of diapause.

Sorry if I sound clueless! LOL

 

[Tom]

I think diapause is when human women are past their reproductive years: they quit having menstrual periods, have hot flashes, get b*tchy and develop moustaches...

Joke of the day. Right here folks!!!

 

[Tom]

Brumation, reminds of when I brought a new broom for the kitchen, wif said what's this for, I said it's your new car! LOL She didn't think it was funny...

Did she Broomate YOU after that comment? I'd have to run or duck if I let one like that fly...

 

[Tom]

Some tortoises lay their eggs at the end of summer, fall or even in winter. For these species the eggs will not develop until they have undergone a cooling period. This basically simulates "winter". After the cooling period, you gradually warm them up (like spring) and then they develop normally once incubation temperatures are reached. The diapause period has nothing to do with sex determination. THAT is determined by the incubation temps once development starts after the diapause has been successfully completed.

This is not necessary for all species. I have however found it to increase the hatch ratio in sulcatas which was a big surprise since they don't need a diapause.

 

[tortadise]

I do have to add. Diapause can also be achieved through different humidity elevations and or drops. As stated Yvonne touched upon it (drought). Humidity can get very detailed and very extensive. Knowing how to utilize the 3 types of humidity can achieve a diapause regime. For instance. Platynota benefits from a short cooling
Periods usually 30-34 days or so. During this cooling period it seems complete dryness is the factor here, and then elevating the temperature to room temp then proceeding with elevated humidity and higher temps for incubation.

 

[Kapidolo Farms]

Diapause = arrested development. There are several adaptive types. One type all chelonians have - It is when the egg is ready to be laid developmentally, but the female has not yet laid the egg(s). It could be due to being disturbed during an initial egg laying process, or inclimate weather, etc. One species of side neck in Australia uses this to offer protection for the female. She lays her eggs while under water, and development does not start until the water recceeds and the egg is exposed to air that inundates the soil. Egg laying is done towards the end of the rainy season when water levels are their highest. Then as the water receeds the eggs begin to develop. This way the adult female is not exposed to terrestrial predators. Even more facinating, to me, is that this is a sort of extension of the one type of diapuase, is that the female behaviorly is in line with the egg's physiology, both had to develope in parallel. I looked at some of the egg pysiology in a electron microscopy lab, those eggs are structuraly different than other sideneck in the same genus, and several other specie's turtle eggs that I tested.

More later on other types of arrested development.

 

[Kapidolo Farms]

Another type of diapause occurs with fully developed eggs waiting for some environmental signal saying, "hatch now". Most often this is temperature, but at least in one case it's an apoxic (no air) environment. Pig nosed turtles lay their eggs during the dry season with low water levels in rivers. Those eggs fully develop and yet the neonates stay in their eggs untill the river beaches become flooded. The lack of air in this situation signals to the neonates, "it's time to hatch". The adaptive advantge here is that the neonates are not exposed to predators. Here's a video

Fully developed neonates that use temperture as a signal, completed their egg bound developement the previous warm season. They overwinter in the egg itself (different than over wintering after hatching, but still in the nest chamber). When the temperture reaches a spring high, they hatch and then emerge.

Still more later.

 

[keepergale]

Yay Will. Good stuff.


Sent from my iPhone using TortForum

 

[Star-of-India]

Great and very informative!

 

[John Ramos]

Joke of the day. Right here folks!!!

Ain't no joke, Tom....Hahaha

 

[Tom]

Ain't no joke, Tom....Hahaha

Oh. You must be married too.

 

[John Ramos]

Oh. You must be married too.

Sho nuf! I love it that a woman could say that, if we say it, we'd be killed!

 

[Kapidolo Farms]

Another system of egg laying and development was reported in a scientific mumbo jumbo journal called "Chelonian Conservation and Biology". In a group of wild three striped mud turtles at least three strategies were discovered going on simultaneously in one population. The females had three peaks of egg laying activity, with each cohort of eggs developing and emerging at different peaks. This would lead to low incidental take by predators as there would be no single ‘best’ time to exploit the turtles for food.

Early spring egg layers' neonates emerged in late summer, and had plenty of time to eat and be active before the cold of winter.

Mid-summer egg layers production hatched but stayed in the nest over winter (not really a diapause in the egg development-physiological sense) . Those neonates emerged very early in the spring, and would have all summer to grow and develop.

Finally the last egg laying peak of the year was fall. Those eggs may or may not grow some before they stop development for the winter. Next spring when temperatures got high enough, egg development would start or continue. These hatchlings would be late spring/early summer emergers.

This is a diversity of ways to reduce the aspect/nature of being food for predators and would tend to reduce the season’s eggs all going bad due to unfavorable climate for any given year. Michael Ewert was one of the authors, and a well regarded chelonian egg development expert. Those scientists, always making nature so interesting through careful observation, damn mumbo jumbo.

 

[ThreeTs]

Does this happen to Russians? Mine laid an egg on 6/25 and it still hasn't hatched yet. Im wondering if it's taking longer to develop this time for some reason. The egg doesn't appear to be bad as of yet..