Diapause in 3 striped mud turtles

[Kirkie]

I've done it, I've broken the diapause on a K.Baurii egg laid 27th January!

Month in the incubator, month cooling and a return to the incubator didn't kick start it. *So since early April its been in an unheated room at about 18C initially.
I had a quick look tonight and the warm weather has kick started this one. It has blood vessels and everything. It's now in the incubator with the others.

I'm quite pleased with that. I can't believe it actually worked.

[Geomyda]

Originally Posted by Kirkie

I've done it, I've broken the diapause on a K.Baurii egg laid 27th January!

Month in the incubator, month cooling and a return to the incubator didn't kick start it. *So since early April its been in an unheated room at about 18C initially.
I had a quick look tonight and the warm weather has kick started this one. It has blood vessels and everything. It's now in the incubator with the others.

I'm quite pleased with that. I can't believe it actually worked.

Well done, isn't Biology magic!

[EJ]

You seem to have researched this well... there has to be a trigger to induce the necessity of a diapause. If that trigger is not innitiated a diapause is not necessary.

This species lays and hatches throughout its active season. That season is highly variable depending on geographical location. It has a huge range.

My point... is it a necessity

Originally Posted by Kirkie

I've done it, I've broken the diapause on a K.Baurii egg laid 27th January!

Month in the incubator, month cooling and a return to the incubator didn't kick start it. *So since early April its been in an unheated room at about 18C initially.
I had a quick look tonight and the warm weather has kick started this one. It has blood vessels and everything. It's now in the incubator with the others.

I'm quite pleased with that. I can't believe it actually worked.

[Kirkie]

I can't figure it. A clutch of four eggs were laid late January. All initially banded and I could see what appeared to be an embryonic turtle in each. Two eggs, (all kept at the same temperature/humidity in very close proximety to each other) developed and have since hatched. The other two paused. This egg is one of those two, the other shows no further signs of development. So in this case I feel it was a necessity and I think the longer drop to low temperatures cued the development when warmer temperatures arrived. I've seen suggestion that, with Baurii at least, it may be the conditions the female encounters pre ovipositon that dictates the diapuse. A cooling of the female then returning to a warmer environment for laying seems to discourage diapuse in this species.*
Diapause/development splits have been registered in single clutches much as has happened with mine. The eggs were in the nest less than 12 hours so I dont think any temperature varience there is tge cause. All the "spring" eggs laid have gone straight into development.

Another thing I've found is that you can persuade the hatchlings to emerge if you take the eggs out of the incubator for a few days when candling shows no visible yolk sac. (actually one had a visible yolk sac but the temp drop seemed to encourage it to catch up and it hatched a day after the other one with a fully absorbed yolk sac).
I had read reports of these turtles dying in the shell waiting for a hatching cue. A drop in temperature and high humidity must replicate a natural hatch cue for this species. Rains most likely.

I forgot to send you the diapause study for K.Baurii, I'll dig it out.

[EJ]

As you went through this I had the thought that there might be a genetic factor... not to throw another wrench in the works.

Some populations that are on the border of the ranges where diapause is required for survival might be inclined to go one way or the other.

I still believe that there is a trigger to require the action one way or the other.

No matter how careful some keepers are I really don't think they get it right to 'figure it out'.

I love this... 'you just can't fool mother nature.'

Originally Posted by Kirkie

I can't figure it. A clutch of four eggs were laid late January. All initially banded and I could see what appeared to be an embryonic turtle in each. Two eggs, (all kept at the same temperature/humidity in very close proximety to each other) developed and have since hatched. The other two paused. This egg is one of those two, the other shows no further signs of development. So in this case I feel it was a necessity and I think the longer drop to low temperatures cued the development when warmer temperatures arrived. I've seen suggestion that, with Baurii at least, it may be the conditions the female encounters pre ovipositon that dictates the diapuse. A cooling of the female then returning to a warmer environment for laying seems to discourage diapuse in this species.*
Diapause/development splits have been registered in single clutches much as has happened with mine. The eggs were in the nest less than 12 hours so I dont think any temperature varience there is tge cause. All the "spring" eggs laid have gone straight into development.

Another thing I've found is that you can persuade the hatchlings to emerge if you take the eggs out of the incubator for a few days when candling shows no visible yolk sac. (actually one had a visible yolk sac but the temp drop seemed to encourage it to catch up and it hatched a day after the other one with a fully absorbed yolk sac).
I had read reports of these turtles dying in the shell waiting for a hatching cue. A drop in temperature and high humidity must replicate a natural hatch cue for this species. Rains most likely.

I forgot to send you the diapause study for K.Baurii, I'll dig it out.

[Kirkie]

This is a good read.

http://rspb.royalsocietypublishing.o...2012.0100.full

[justmeandmytortoise]

Oh my ... cannot wait to follow this one through

[Kirkie]

Originally Posted by justmeandmytortoise

Oh my ... cannot wait to follow this one through

Just don't ask me to do a talk on it. I have no idea how this has happened.

[Kirkie]

Originally Posted by Kirkie

This is a good read.

http://rspb.royalsocietypublishing.o...2012.0100.full

Another possibility is that the female "decides" at point of oviposition.

From the above:

"In the oviduct, the external environment consists of an oviducal material that bathes the egg and fills the shell pores. Proteins have been identified in the oviducal fluid of some reptilian species including the estuarine crocodile, Crocodylus porosus; the American alligator, Alligator mississippiensis [17]; and the gopher tortoise, Gopherus polyphemus [18], although there is still little known of the composition and function of the majority of oviducal products. The transfer of growth factors secreted by the oviduct of gravid A. mississippiensis has been shown to affect embryonic development after being taken up by the egg. However, the significance of the transfer of such materials is not fully understood."

[Kirkie]

The date marked on the egg says 24/1/12...and tonight it's pipped. It's on the way. Its clutch mates are 4 months old!