Painted turtles, male, female, new research


This 6 May 2018 video from the USA says about itself:

In this video I will show you these cute amazing baby painted turtles. These baby turtles are only 1 day old and are so tiny, some of these baby turtles are the size of quarters and smaller. I saved the baby painted turtles from birds and at the end of the video I will let these turtles go.

From Iowa State University in the USA:

How scientists view sex determination in painted turtle populations

August 6, 2019

Summary: A study that looks at how temperature influences the development of painted turtles may lead biologists to rethink the theoretical frameworks they use when analyzing the topic. The study found wide variation within local populations, suggesting temperature sensitivity of embryonic development can vary significantly from one turtle nest to another within a single population.

A new study from Iowa State University scientists could flip the established framework for how scientists believe geography influences sex determination in painted turtles on its shell.

The study, published Tuesday in the academic journal Functional Ecology, analyzed decades of data concerning painted turtles, a species widely distributed across North America that undergoes temperature-dependent sex determination. That means the temperatures experienced by an incubating painted turtle egg influence whether an embryo develops the physical characteristics biologists describe as male or female. Warmer temperatures tend to produce females, and cooler temperatures tend to produce males.

The study’s findings defied theoretical expectations for how painted turtle populations respond to environmental variation, which could lead scientists to rethink how they look at the topic, said Anna Carter, a postdoctoral research associate in ecology, evolution and organismal biology and lead author.

Painted turtles cover a vast geographical range, from New Mexico to Canada. That means populations experience wide variation in temperatures and environmental conditions. For years, scientists emphasized “pivotal temperature”, or the temperature that produces an equal number of males and females in a given population, when studying how the turtles respond to environmental variation. This framework would expect populations that live in warmer regions to have a higher pivotal temperature as well.

Previous studies found patterns related to latitude, Carter said. The closer a population was to the equator, the higher its pivotal temperature. But using a massive dataset on painted turtle populations allowed the scientists to take an unprecedented look at the relationship between latitude and pivotal temperature, and the new analysis didn’t find a convincing pattern.

Instead, the researchers found wide variation in pivotal temperature within local populations, as much as 5 degrees Celsius. The finding suggests temperature sensitivity of embryonic development can vary significantly from one turtle nest to another within a single population.

“The implication of our study is that our understanding of local adaptation in this species isn’t as good as we thought it was,” Carter said. “It might be useful to move away from pivotal temperature as a model.”

The study, however, did find patterns connecting geography to the transitional range, or the range of temperatures that produce a mix of males and females. Transitional ranges tended to be wider at lower latitudes, Carter said.

The unexpectedly wide variation in pivotal temperature within populations could suggest painted turtles are more resilient to changes in temperature than previously thought. It’s possible female painted turtles can nest successfully in a multitude of environments, they said.

The study drew on a huge dataset collected over the span of decades by Fred Janzen, a professor of ecology, evolution and organismal biology, and his colleagues. Janzen said his lab has collected data on painted turtle populations on the Mississippi River near Clinton for 32 years. The data includes nesting and temperature measurements.

“I’ve been truly fortunate to meet folks willing to put in the time and effort to do this work,” Janzen said. “It’s a big ask. We’re talking about year after year of each group putting together their own field crew to follow a turtle population.”

For the study, the researchers modeled temperature dependent sex determination in 12 geographically distinct painted turtle populations using both field data and lab incubation experiments.

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Turtle embryos help determining their own sex


This March 2019 video says about itself:

BABY SEA TURTLE HATCHING

In summer time when the weather is warm, pregnant female sea turtles return to the beaches where they themselves hatched years before. They swim through the crashing surf and crawl up the beach searching for a nesting spot above the high water mark. Using her back flippers, the reptile digs a nest in the sand. Digging the nest and laying her eggs usually takes from one to three hours, after which the mother turtle slowly drags herself back to the ocean.

From ScienceDaily:

Turtle embryos play a role in determining their own sex

August 1, 2019

In certain turtle species, the temperature of the egg determines whether the offspring is female or male. But now, new research shows that the embryos have some say in their own sexual destiny: they can move around inside the egg to find different temperatures. The study, publishing August 1 in the journal Current Biology, examines how this behavior may help turtles offset the effects of climate change.

“We previously demonstrated that reptile embryos could move around within their egg for thermoregulation, so we were curious about whether this could affect their sex determination,” says corresponding author Wei-Guo Du, professor at the Chinese Academy of Sciences. “We wanted to know if and how this behavior could help buffer the impact of global warming on offspring sex ratios in these species.”

Du and his colleagues incubated turtle eggs under a range of temperatures both in the laboratory and in outdoor ponds. They found that a single embryo could experience a temperature gradient of up of 4.7°C within its egg. This is significant because any shift larger than 2°C can massively change the offspring sex ratio of many turtle species, Du said.

In half of the eggs, they applied capsazepine, a chemical that blocked temperature sensors, to prevent behavioral thermoregulation. After the eggs hatched, the researchers found that the embryos without behavioral thermoregulation had developed as either almost all males or almost all females, depending on the incubation temperatures. In contrast, embryos that were able to react to nest temperatures moved around inside their eggs; about half of them developed as males and the other half as females.

“The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg,” Du says.

By moving around the egg to find what Richard Shine, a professor at Macquarie University of Australia and one of the co-authors, calls the “Goldilocks Zone” — where the temperature is not too hot and not too cold — the turtles can shield against extreme thermal conditions imposed by changing temperatures and produce a relatively balanced sex ratio. “This could explain how reptile species with temperature-dependent sex determination have managed to survive previous periods in Earth history when temperatures were far hotter than at present,” he says.

But this behavior has limitations, Du says, depending on the conditions of the egg and the embryo itself. “Embryonic thermoregulation can be limited if the thermal gradient within an egg is too small, or if the embryo is too large to move around or too young to have developed these abilities yet,” he says.

Additionally, the behavior cannot buffer the impact of episodes of extremely high temperatures, which are predicted to increase with climate change, Du says.

“The embryo’s control over its own sex may not be enough to protect it from the much more rapid climate change currently being caused by human activities, which is predicted to cause severe female-biased populations,” he says. “However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges.”

Du says that this study indicates that these species may have some ways not yet discovered to buffer this risk. “Our future studies will explore the adaptive significance of embryonic thermoregulation as well as the other behavioral and physiological strategies adopted by embryos and mothers to buffer the impact of climate warming on turtles.”

What is inside turtles’ shells?


This 9 July 2019 video says about itself:

What’s Inside A Turtle Shell

A turtle can’t crawl out of its shell. In fact, the shell is actually part of a turtle’s skeleton, as much of our ribcage is of ours. But if you could peer inside a shell, you’d find some of the most unusual features in the animal kingdom, such as a butt — err, cloaca — that some species use to breathe underwater.

Good Brazilian leatherback turtle news


This December 2017 video is called Protecting leatherback turtlesBlue Planet II: Episode 7 Preview – BBC One.

From the University of Exeter in England:

‘Gentle recovery’ of Brazil’s leatherback turtles

July 1, 2019

Brazil’s leatherback turtles are making a “gentle recovery” after 30 years of conservation efforts, new research shows.

Scientists studied nesting sites in the state of Espírito Santo in eastern Brazil — the only place in the south-west Atlantic where leatherbacks regularly nest.

Data on this small population from 1988-2017 showed the average number of nests rose from 25.6 in the first five years of the period to 89.8 in the final five years.

The researchers, from the University of Exeter and Brazilian sea turtle conservation programme TAMAR-ICMBio, believe local conservation efforts have contributed to this increase.

But they say conservation of this population is still a concern due to climate change, pollution, coastal development and “bycatch” (accidental catch by humans fishing).

“The numbers vary year by year, but overall we have seen an increase in the number of leatherback nests in Espírito Santo,” said Dr Liliana Poggio Colman, of the Centre for Ecology and Conservation on the Exeter’s Penryn Campus in Cornwall.

“This gentle recovery is probably due, at least in part, to local conservation efforts started by Projeto TAMAR in the 1980s.

“Our study revealed a significant decrease in the size of the turtles breeding on these beaches, suggesting that new females are joining the breeding population.”

Dr Poggio Colman, who had a scholarship from the programme Science Without Borders, funded by the Brazilian government, added: “We are encouraged by what we have found, but this is a small population — fewer than 20 nesting females per year, each laying several clutches — so their conservation will remain a concern.”

Throughout the study period, nests were concentrated in the southern part of the 100-mile (160km) study area, with the protection of core nesting areas being key for the effective conservation of this population.

Professor Brendan Godley, who was one of Dr Poggio Colman’s PhD supervisors, added: “It was a great pleasure to help facilitate this collaborative work in Brazil.

“By chance, the team was in the field when a major spill of waste mining material impacted in the area in 2015. Average hatching success has, however, remained fairly steady at about 66%.”

Now, let us hope that extreme right Brazilian president Bolsonaro will not manage to damage this recovery; like he damages the Brazilian Amazon rainforest.

Saving South American river turtles


This 2015 video says about itself:

The giant South American river turtle is not as abundant as it once was in some areas, but conservation methods—including patrols of nesting beaches by armed guards—help Brazil maintain a healthy population. Here turtles interacting with one another underwater are observed, for what could be the first time.

From the Wildlife Conservation Society:

Conservation efforts for giant South American river turtles have protected 147,000 females

The paper surveyed 85 conservation projects that protect the ‘charapa’ in the Amazon and Orinoco river basins

June 25, 2019

By analyzing records in countries of the Amazon and Orinoco basins — which include Brazil, Venezuela, Colombia, Bolivia, Peru and Ecuador — a paper published today in Oryx — The International Journal of Conservation, categorized 85 past and present initiatives or projects that work to preserve the South American River Turtle, or charapa (Podocnemis expansa), a critically endangered species. These projects are protecting more than 147,000 female turtles across the basin, an unprecedented figure.

The paper “On the future of the giant South American river turtle, Podocnemis expansa” was drafted by 29 Latin American researchers and scientists, including WCS’s German Forero Medina, Camila R. Ferrara, and Camila K. Fagundes, Ruben Cueva, and Brian D. Horne. The collaboration stems from a 2014 workshop held in Balbina, Brazil in which park rangers, indigenous people, and conservationists from the six countries provided information on their work to protect the charapa. The efforts discussed in that continental meeting and subsequent study reveal the serious commitment of public and private entities to conserve the species.

The charapa is considered the largest river turtle in South America. It inhabits the tributaries of the Amazon and Orinoco river basins, and is an important cultural symbol for many communities in the region. It also has great ecological importance for ecosystems, as it helps transport fruits and seeds along the rivers and serves as prey for birds, catfish, foxes, jaguars, alligators, and water dogs. In the twentieth century, hundreds of thousands of turtles spawned on beaches throughout the continent.

Despite their local importance and past abundance, turtle populations are still threatened by the hunting and collection of adults and juveniles, looting of nests, the illegal trafficking of hatchlings to be used as pets, and the use of inappropriate fishing gear which can harm or kill individuals. In addition, broader degradation of their habitat is contributing to their decline.

Germán Forero, Scientific Director with WCS Colombia and lead author, called for the creation of a protection network for the charapa — a regional monitoring program that would link technical information and lessons learned among all the projects in the six countries. He noted the importance of communities in this future network.

“The participation of local communities that live with the charapa is essential to protecting them,” said Forero. “They live side by side with the turtles and are interested in controlling or preventing the commercialization of eggs or meat to ensure the ongoing sustainability of the species as a food source and important part of their culture.”

Camila Ferrara, co-author and researcher with WCS Brazil, added that the formation of this network would be extraordinary, because it would allow stakeholders to design and assess methodologies for management and conservation of the species, from its gestation and protection of nesting beaches to population monitoring.

In Brazil, the charapa is not considered critically endangered, but a near-threatened species. Ferrara explains that although Brazil is home to important populations of the species, the turtle is still the second most consumed vertebrate group in the Amazon, surpassing even some fish. Therefore, she believes that the network should focus their efforts on strengthening environmental education in Brazil to ensure the sustainability of the reptile’s consumption.

Ferrara said: “We are seeing positive results as work progresses, as communities are expressing greater interest in working with turtles. We have seen a decrease in the consumption of eggs, an important achievement that we must replicate throughout the continent.”

The paper highlights the importance of the monitoring conducted by the Brazilian Institute of the Environment and Renewable Natural Resources (IBAMA), which provides the only way to assess the trends of populations over time and thus is valuable information for decision-making on the species.

In Colombia, initiatives are working to protect at least two large populations, one in the Caquetá River in the Amazon basin and another in the Meta River in the Orinoco basin. In both areas, local communities are committed to protecting the nesting females at beaches, and these programs are expected to receive continued support over time.

Going forward, the proposed network plans to develop a platform that can serve as an observatory of the species, tracking population trends across the basin over time to prioritize intervention sites and ensure the long term conservation of the species.

This paper reviews a diversity of initiatives that seek to recover these turtle populations. Rick Hudson, President of the Turtle Survival Alliance (TSA), believes that interest in protecting the charapa in South America comes at an opportune moment, as there are still robust populations of river turtles to protect; this is not the case in Asia, where many of turtle species have gone extinct.

Hudson said: “The lesson is clear: protect the habitat and large nesting aggregations of river turtles now and avoid crisis management in the future. This paper makes a strong case for improving levels of protection while there is still time.”

Curing sick green turtles, new research


This is a 2010 video about green turtles from the BBC’s Life in Cold Blood documentary series.

From James Cook University in Australia:

Good viruses and bad bacteria: A world-first green sea turtle trial

June 19, 2019

Summary: A world-first study has found an alternative to antibiotics for treating bacterial infections in green sea turtles.

Researchers at the JCU Turtle Health Research Facility have conducted a first-of-its-kind study using what’s known as phage therapy as an option for bacterial infections in green sea turtles.

Phage therapy uses so-called ‘good viruses’ (bacteriophages) that occur naturally in the environment and kill bacteria.

Green turtles rely on ‘good bacteria’ in their gut to extract nutrients from food,” said Dr Robert Kinobe, one of the researchers involved in the study.

“This creates a challenge when it comes to treating bacterial infections because if we administer antibiotics, it can destroy the ‘good bacteria’ and make the turtle’s health worse.”

Researchers at the JCU Turtle Health Research Facility applied ‘good viruses’ to green sea turtles and found that it was successful in eliminating the targeted ‘bad bacteria’ without hampering the non-targeted ‘good bacteria’.

“This shows that phage therapy can be safe and effective enough to manipulate or treat targeted bacteria in green sea turtles,” said Dr Kinobe.

A further complication, previously identified by the JCU Turtle Health Research Facility, is the existence of antibiotic-resistant bacteria in the guts of green sea turtles, which are found in several locations along the Queensland coast.

“Antimicrobial resistance is one of the most critical issues we face, which is why this finding of an alternative to antibiotics is so important,” said co-author Dr Lisa Elliott.

“Bacteriophages and phage therapy have already been suggested as an alternative for antibiotics in humans, but we also need to investigate its scope for treatment in animals.”

The research has been published in the Journal of Environmental Microbiology and opens the door for future applications of phage therapy as an alternative to antibiotics in treating bacterial infections in turtles and other marine animals.