Based on the findings during a field study, John B. Iverson wrote “Reproduction in the Red-Cheeked Mud Turtle (Kinosternon scorpioides cruentatum) in Southeastern Mexico and Belize, with Comparisons Across the Species Range,” Chelonian Conservation and Biology.
This book published in 2010. The study was in southeastern Mexico and Belize in the Yucatan Peninsula based on museum and field-collected specimens. Adult females were not significantly larger than adult males and were an estimated age of 9–10 years.
Annual reproduction by females was continuous for at least 10 months of the year in August, May, and June, with the production of multiple annual clutches. Reports are as many as 5 being typical and the number of clutches per year increasing with female size.
Eggs exhibit diapause and embryonic estivation and hatch in nature during the wet season in June, July, or August after up to 9 months in the nest. The average clutch size was only 2 eggs but the clutch size increased with female body size.
Females devote a relatively constant proportion of body mass to each clutch, and increases in reproductive output with size and age are accomplished by increases in clutch size (but not egg size) and clutch frequency.
This unusual suite of reproductive traits based on small body size, small clutch size, production of up to 5 clutches per year, reduced relative clutch mass, and embryonic diapause and estivation may have been instrumental in the success of this species at colonizing more of South America than any other Mesoamerican turtle genus or species and in less than 4 million years.
Arrested embryonic development involves the downregulation or cessation of active cell division and metabolic activity, and the capability of an animal to arrest embryonic development results in temporal plasticity of the duration of the embryonic period. Arrested embryonic development is an important reproductive strategy for egg-laying animals that provide no parental care after oviposition.
Oviposition is the term used to describe the laying of eggs.
Arrested embryonic development is an adaptation characterized by the downregulation or cessation of active cell division and metabolic activity of the embryo.
It is a reproductive strategy that is employed by many taxa including plants, insects, and amniotic vertebrates, suggesting that it has evolved independently on numerous occasions. This life-history trait confers a significant selective advantage because it allows embryos to respond to varying environmental conditions by altering their period of development.
K. scorpioides embryos experience diapause. This is a duration in which the growth or development of the embryo is decreased, as well as, physiological activity in response to changes in environmental conditions.
The development of the embryo is delayed until this duration is interrupted by environmental factors, such as, warming after a cold period. Besides diapause they also seem to exhibit estivation. Embryos that have reached the hatching stage are only triggered to hatch when the conditions are suitable and for this to occur their metabolism is reduced to prevent them from depleting their food resources inside the shell until the time is appropriate, similar properties to hibernation.
The purpose of these mechanisms aid in synchronizing hatching to start at the beginning of the summer rainy season. Many reptiles sex is determined by the temperature of the nest.
Normally a higher temperature will produce males while lower produce females or vice versa. The sex of the K. scorpioides is a bit different where the temperature changes either high or low will produce the females and temperatures in between give rise to male production
How did we get the Red-cheek Mud Turtles to hatch here at Crazy Critters Inc.?
It is always difficult knowing how to hatch a new species of animals. This is especially true with turtles. When it came to the Redcheecked Mud Turtle, we got even more nervous once we were told the species were maybe going to be added to Cites in the future.
Even if they are not, male turtles of this species are very difficult to find, especially here in Florida. After searching for any reports on egg incubation in this species, I found a paper by Jonathan González that was published during a conference in 2015, detailing hatching information.
His conclusion suggests that vermiculite as an incubation medium has a higher pH, while a lower pH medium such as peat moss causes slight degradation of the eggshell during incubation, aiding the hatching process.
We used a commercial incubator set at 87 degrees for 190 days. On the 120th day we began to add moisture to replicate the wet season.
I haven’t found confirmation by a reputable source on the technical developmental diapause in Red-cheeks. However, there may be periods of embryonic inactivity, but nothing requiring a terminating trigger.
Most importantly, there is a delayed hatching, which is a type of diapause. We keep it fairly humid throughout the incubation and raise humidity at around 90-100 days.
Day 122… baby turtles! How cool is that?
You Can NOT Make This Stuff Up!!!
I was finished with this page on Sunday May 25. 2020 sometime around lunch.
I feel pretty proud of ourselves for just housing turtles well enough to make them happy and healthy enough to lay eggs.
More proud that we have helped them be healthy enough to have fertile eggs. EVEN more proud of hatching this specific species and gaining the first-hand experience to create and publish such a page.
As our day went on, we got really busy with cleaning water bowls, raking out enclosures, and what we call poop patrol. The day even had a strange dog in our field biting our cows. We caught our day and you can see just a small piece of it in this video. WAIT till you see what our day ended with! You will NOT believe this!
This Is The Craziest Timeline!
October 18, 2019 new eggs. This first clutch was not supposed to happen! These turtles were not acclimated or anything. They were in quarantine at the time when we found an egg in the water so we knew to give them a nesting spot.
May 7, 2020, SECOND clutch begins to hatch…
May 8, 2020, All four turtles are out of the eggs….
May 25, 2020 baby from FIRST clutch hatched…
That is 220 days!!!!
The eastern (U.S.) mud turtle (Kinosternon subrubrum) has somewhat longer incubation with diapause as long as 12 months before it begins to incubate for hatching.
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