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Turtles and tortoises (Order Testudines) are facing an extinction crisis, and ecosystems are at risk of collapsing with the loss of key roles they play. Hatching failure is a crucial barrier to population growth and persistence, but its causes are poorly understood, and it is unknown whether fertilization rates are declining as many populations become smaller and more female‐biased. Here, we show that very few studies of turtle and tortoise hatching success consider fertilization rates, and those that do use unreliable methods to determine egg fertility. We also show that studies of hatching success are biased towards marine turtles, as opposed to freshwater and terrestrial species, and wild rather than captive populations. To address the lack of reliable methods for assessing fertilization rates in turtles and tortoises, a microscopy‐based method (originally designed for bird eggs) for detecting perivitelline membrane (PVM) bound sperm and embryonic nuclei in the germinal disc of unhatched eggs has been developed and tested (in turtle and tortoise eggs). We demonstrate that this method provides unequivocal evidence of egg fertilization in five different turtle and tortoise species from both captive and wild populations, even after eggs have been left in wild nests for the full incubation period. This methodological approach represents a valuable tool for monitoring egg fertility and embryo survival rates in turtles and tortoises, with the potential to provide important insights into the underlying drivers of reproductive failure in threatened captive and wild populations. [ABSTRACT FROM AUTHOR]

This article examines the role of embryonic behavioral thermoregulation in turtle hatchlings. The study conducted experiments using turtle embryos and hatchlings to investigate the effects of manipulating embryo thermotaxis. Contrary to the hypothesis that thermotaxis represents play behavior, the results showed that embryonic behavioral thermoregulation did not significantly impact the thermoregulatory behavior of hatchlings. However, the study suggests that this behavior benefits both embryos and offspring by improving developmental success and affecting offspring sex ratios. Further research is needed to understand the influence of embryonic behavioral thermoregulation on younger hatchlings. [Extracted from the article]

We studied the diet of Western Hog-nosed Snakes (Heterodon nasicus) that were captured opportunistically from 1988 to 2017 at a wetland complex in the Sandhills of western Nebraska. Only 30 of 92 snakes (33%) held food items (n = 33) in their stomachs, including anurans (3 cases), salamanders (2 cases), lizards (2 cases), turtles (22 cases, most as eggs), rodents (3 cases), and an unidentified vertebrate bone (1 case). The large, local population of Painted Turtles (Chrysemys picta), producing up to 3 clutches of up to 22 eggs per clutch each year from mid-May to mid-July, no doubt explains the preponderance of turtle eggs in the snakes' diet. It may also explain why Western Hog-nosed Snakes seem to be most abundant near wetlands in this and other parts of their range. [ABSTRACT FROM AUTHOR]

Copyright of Sultan Qaboos University Journal for Science is the property of Sultan Qaboos University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Unsustainable wildlife trade is a major contributor to biodiversity loss; however, trade regulations have failed to prevent the decline of high‐profile species. Where wildlife is traded legally, opportunities exist to launder protected species through legal channels. The legal commercialization of olive ridley sea turtle eggs from Ostional, Costa Rica, has been criticized with some suggesting that the legal trade stimulates illegal extraction and sale of eggs. We aimed to identify whether the traceability rules, under which the Ostional project operates, were suitably robust. We surveyed markets across Costa Rica, by purchasing openly available sea turtle eggs and recording qualitative and quantitative data at the point of sale. We found that 378 (80%) of turtle eggs openly sold in the market were from olive ridley sea turtles. Green (n = 5) and leatherback (n = 6) turtle eggs were only on offer on three occasions, but no vendor referred to Ostional. Vendors frequently breached trade regulations, which appeared to be due to these regulations misaligning with consumer demand. Although the Ostional traceability rules are regularly flouted, we found no evidence that Ostional is being used as a cover to sell eggs from other turtle species. [ABSTRACT FROM AUTHOR]

Turtle nesting habitat can be created as a restoration strategy to increase habitat availability or provide suitable habitat away from threats. Traditional nest habitat restoration consists of creating nesting mounds using a mix of sand and gravel. However, nesting mounds do not resemble natural turtle nesting habitat in a rock barren landscape where turtles nest in crevices and cracks in the bedrock. Therefore, our objective was to design and evaluate the success of a landscape‐appropriate design for turtle nesting habitat in a rock barren landscape. To evaluate success of the nest habitat design, we assessed the (1) survival of transplanted moss and lichen cover on created nest sites, (2) ecohydrological and physical conditions at created and natural sites, and (3) turtle egg hatching success at created and natural sites using a split‐clutch experiment. We found no difference in productivity between lichen transplants and natural sites, indicating that intact lichen transplants were successful. Moss transplant success was more variable due to moisture stress because transplants were conducted during dry conditions. In general, created nest habitat tended to have a more stable thermal and moisture regime compared to natural sites. When accounting for maternal effects, the odds of an egg hatching successfully was 6.6 times higher in a created site than a natural site. Overall, the success of our nest habitat design in the first few years suggests that this landscape‐appropriate design will be a useful restoration strategy for increasing turtle nesting habitat in rock barren landscapes. [ABSTRACT FROM AUTHOR]

Ghost crabs can be abundant at beaches where sea turtles nest, but the food web dynamics are poorly understood. Using multiple dietary methods, our research aimed to characterise the diet of the golden ghost crab Ocypode convexa at rookeries of the loggerhead turtle Caretta caretta on the west coast of Australia, with a focus on determining the importance of sea turtle eggs and hatchlings to its diet. We achieved this through combining complementary methods: gut content analysis (GCA); DNA analysis of gut contents; stable isotope analysis (SIA); and controlled feeding experiments. GCA showed that O. convexa is a facultative scavenger with an omnivorous diet comprising high contributions (> 55%) of abundant beach-cast leafy brown algae. However, DNA analysis identified C. caretta in ≥ 20% of crab guts, and stable isotope mixing models suggested that sea turtle contributed 40–62% of assimilated C and N for male and 21–40% for female ghost crabs during the nesting season, while other animal and algal sources were also likely to be consumed when sea turtle eggs and hatchlings were absent or present. Aquarium-based feeding assays showed that ghost crabs prefer sea turtle and fish carrion over leafy brown algae (0.81 vs 0.10 vs 0.03 g/h consumed). Sea turtles provide large amounts of nutrients to consumers in the form of eggs and hatchlings, and golden ghost crabs benefit substantially from this pulsed resource along the Ningaloo coast, a World Heritage Area. Through the combined use of SIA, GCA, DNA, and feeding trials, this study highlights the important roles of both sea turtles and ghost crabs in energy fluxes and nutrient cycling at generally nutrient-poor sandy beach ecosystems. However, high consumption rates in the region can possibly put the long-term survival of the C. caretta population at risk. [ABSTRACT FROM AUTHOR]

Evaluating the effects of temperature variations on animals plays an important role in understanding the threat of climate warming. The effects of developmental temperature on offspring performance are critical in evaluating the effects of warming temperatures on the fitness of oviparous species, but the physiological and biochemical basis of this developmental plasticity is largely unknown. In this study, we incubated eggs of the turtle Pelodiscus sinensis at low (24 °C), medium (28 °C), and high (32 °C) temperatures, and evaluated the effects of developmental temperature on offspring fitness, and metabolic enzymes in the neck and limb muscles of hatchlings. The hatchlings from eggs incubated at the medium temperature showed better fitness-related performance (righting response and swimming capacity) and higher activities of metabolic enzymes (hexokinase, HK; lactate dehydrogenase, LDH) than hatchlings from the eggs incubated at high or low temperatures. In addition, the swimming speed and righting response were significantly correlated with the HK activities in limb (swimming speed) and neck (righting response) muscles, suggesting that the developmental plasticity of energy metabolic pathway might play a role in determining the way incubation temperature affects offspring phenotypes. Integrating the fitness-related performance and the activities of metabolic enzymes, we predict that the P. sinensis from high latitude would not face the detrimental effects of climate warming until the average nest temperatures reach 32 °C. [ABSTRACT FROM AUTHOR]

The objective of this study is to assess the occurrence of intestinal parasites in Mediterranean pond turtle Mauremys leprosa leprosa collected from three contrasting environments in Morocco. Stool samples from 92 turtles were examined for parasite detection and enumeration. The identified intestinal parasites belong to helminths (oxyurids and ascarid) and protozoa (Entamoebidae). A total of 25 turtles (27.17%) were found to be infected by helminths and/or protozoan parasites. No adult form of these parasites was detected. Eggs of oxyurid and ascarid were detected in individuals of populations studied from Oued Ksob (23.07% and 30.76% of n = 13 turtles) and Oued Zat (34.14% and 24.39% of n = 41 turtles), respectively. For protozoa, Entamoeba cysts were present in turtles in Oued Ksob (15.38% of n = 13 turtles), Oued Zat (12.19% of n = 41 turtles), and Oued Tensift (5.26% of n = 38 turtles) localities. Oxyurid eggs showed the highest intensity at Oued Zat reaching 29.30 ± 59.59 eggs per gram (EPG), versus 12 ± 0.38 EPG for ascaris eggs in Oued Ksob. Entamoeba cysts were detected in lower levels with a maximum of 1.66 ± 1.50 cysts per gram (CPG), in Oued Zat. The prevalence of turtles eliminating eggs was statistically significant between localities for different parasite groups. This study reports for the first time a parasitological characterization of gastrointestinal parasites in wild populations of M. leprosa leprosa from contrasting environments, suggesting a relationship between turtles' infestation and the quality of their habitat. [ABSTRACT FROM AUTHOR]

Copyright of Jurnal Ilmu dan Teknologi Kelautan Tropis is the property of IPB University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sea turtle hatchlings rely on their finite energy reserve to sustain embryonic development in underground nests and during the first few days of their post-hatch life, including nest escape, beach crossing, and swimming offshore. This study aimed to investigate if the grain size of the nest substrate has an impact on green sea turtle (Chelonia mydas) hatchlings' energy usage during nest escape. About-to-hatch green sea turtle eggs were incubated in laboratory chambers filled with either coarse-grain sand (ϕ = 0.507 phi) or fine-grain sand (ϕ = 2.028) at a temperature of 28°C. Open-flow respirometry was used to measure the hatchlings' oxygen consumption rate during nest escape, which was then converted to energy consumption values. Results showed that hatchling morphology, hatching success, emergence success, and synchronous emergence rate were not significantly different between the groups of hatchlings in coarse versus fine sand. Hatchlings that dug through coarse sand emerged significantly faster (168 ± 13.9 h) than those in fine sand (233.21 ± 12.6 h) (t (26) = -3.473, p = 0.002). Additionally, the hatchlings in coarse sand (310.55 ± 28.1 kJ) consumed significantly less energy than hatchlings in fine sand (474.85 ± 64.7 kJ) (t (17.739) = -2.328, p = 0.032). A difference in amount of energy reserve upon emergence was detected between coarse and fine sand groups. To improve hatchery management practices, relocating "doomed" clutches into coarse sand (ϕ = 0.507) could potentially maximise the hatchlings' energy reserve. [ABSTRACT FROM AUTHOR]

The tufted ghost crab Ocypode cursor (Linnaeus, 1758) found in the Mediterranean Sea and the Atlantic Ocean is currently a great example that elucidates concerns within scientific and conservation communities. This species, native to the subtropical Atlantic Ocean and the warmest southeastern Mediterranean Sea (Egypt), has been extending its distribution in both regions since the 1980s, likely due to the warming sea temperatures. These small nocturn crabs are typically found inhabiting sandy beaches and dune environments. This species is an opportunistic predator eating terrestrial and marine prey, especially on sea turtle eggs. Despite its status as a threatened species by two European conventions, there is a lack of knowledge of its ecology and biology. Sometimes considered as an indicator of good ecological status of beaches where it lives, this ghost crab could nevertheless benefit from climate change to extend its distribution range. This review aims to create a baseline on the current knowledge and gaps in the published scientific literature on the ghost crab. Additionally, through an analysis of the existing literature, we also offer insights into the potential risk of beach erosion associated with the expansion of this species. [ABSTRACT FROM AUTHOR]

This study proposes a novel image segmentation algorithm for estimating the average size of densely packed grains, particles, cells, powders, bubbles, and aggregates. The algorithm comprises two sub-algorithms: valley edge detection and grain size estimation. The valley edge detection sub-algorithm identifies weak edges among grains using four directions. In contrast, the grain size estimation sub-algorithm calculates the average size of the grains based on the detected edge density. The algorithm can recognize grains with circular, elliptical, or other regular shapes without explicitly delineating each grain, making it ideal for complex and densely packed grain images. The algorithm was tested using various samples, including aggregate particles, tomatoes, chicken/duck eggs, turtle eggs, soybeans, lawn seeds, rapeseeds, and other seeds, and the testing results were satisfactory. The proposed algorithm is 200-500 times faster than ordinary grain image segmentation algorithms. It is suitable for online applications that require real-time image processing of densely packed and detailed grain images. [ABSTRACT FROM AUTHOR]

The given document is a compilation of various scientific articles and studies related to the reproduction and care of turtles and tortoises. The articles cover topics such as egg development, incubation, hatching behavior, nutrition, and conservation efforts. The information provided can be useful for researchers and individuals interested in understanding the reproductive biology and management of these reptiles. [Extracted from the article]

Egg predation by invasive and native species may have severe impacts on endangered species and negatively affect species recovery. We assessed the levels of egg predation within green turtle (Chelonia mydas) clutches on the island of Diego Garcia (7.42°S, 72.45°E), Chagos Archipelago (Indian Ocean). Native coconut crabs (Birgus latro) and ghost crabs (Ocypode spp.), as well as introduced black rats (Rattus rattus), were predators of eggs, with these species entering nests via tunnels dug obliquely in the sand. Often whole eggs were removed from clutches. For example, the mean clutch size at oviposition (mean 127.8 eggs, n = 23, range = 74–176) was significantly larger than at the end of incubation (mean 110.9 hatched and unhatched eggs, n = 16, range = 9–147). In other cases, egg predation was recorded where the egg had been opened and contents were eaten in the nest. Overall, hatching success (the percentage of eggs laid leading to a hatchling emerging from the egg) was 64.9%, while 3.1% of eggs were predated within nests, 18.1% died during incubation without predation and 13.9% were removed. We reviewed evidence from 34 sites around the world identifying 36 predators that were either native (e.g., crabs, and goannas, n = 30) or invasive (e.g., rats, and pigs, n = 8). Depending on location, a predator could be identified as both native and invasive (e.g., dogs). We discuss how either nest protection and/or invasive predator eradication may be used to increase egg survival and when these approaches might be used. [ABSTRACT FROM AUTHOR]

Marine subsidies are vital for terrestrial ecosystems, especially low-productivity islands. However, the impact of losing these subsidies on the terrestrial food web can be difficult to predict. We analyzed 23 years of survey data from Orchid Island to assess the consequences of the abrupt loss of an important marine subsidy. After climatedriven beach erosion and predator exclusion efforts resulted in the abrupt loss of sea turtle eggs from the terrestrial food web, predatory snakes altered their foraging habitats. This increased predation on other reptile species in inland areas, resulting in population declines in most terrestrial reptile species. Comparisons with sea turtle-free locations where lizard populations remained stable supported these findings. Our study emphasizes the cascading effects of generalist predators and the unintended consequences of single-species conservation, highlighting the importance of understanding species interconnectedness and considering potential ripple effects in marine-dependent insular ecosystems. [ABSTRACT FROM AUTHOR]

Illegal wildlife trade can threaten biodiversity and economic development. Criminal enterprises may add wildlife products to their list of illicit goods by using established trade routes, networks, and individuals. On the Caribbean coast of Costa Rica, killing of sea turtles and removal of their eggs is commonplace. However, beyond conservation NGOs reporting evidence of illegal take, little is known about this activity. Through semi-structured interviews with law enforcement, community members, NGOs, and illegal harvesters, alongside anecdotal information and observations, we aimed to understand the motivations for illegal take. To cross-reference these findings, we assessed sensitivities surrounding illegal harvesting by asking the general public sensitive questions using the randomized response technique; a method used to elicit sensitive information whilst insuring the anonymity of respondents. We included a questionnaire to establish if differences in demographics affected the probability respondents would admit to a turtle-related crime. Our findings identified a rare example of illegal extraction of a wildlife product driven by motivations that were not exclusively livelihood based. We found the majority of illegal take was undertaken by relatively few individuals, dependent on narcotics. The most cited reason for illegal take was that turtle eggs could be used to procure drugs. Law enforcement was under resourced, and informants reported that prosecutions were rare. Local people preferred to purchase rather than harvest eggs suggesting the trade is supply-driven. Those interviewed did not generally regard the subject of illegal harvest as sensitive. Low education levels, high unemployment rates, and marginalization of certain groups may increase susceptibility to narcotics. Although substance misuse and addiction appear to drive illegal trade, associated poverty and marginalization may explain why drug dependency is so prevalent in Caribbean Costa Rica. Increased work opportunities and drug rehabilitation programs may assist in reducing illegal take of turtle eggs on nesting beaches. [ABSTRACT FROM AUTHOR]

Subsidized predators are animals whose populations proliferate through association with humans. As subsidized predators, birds in the family Corvidae (Corvus spp., crows and ravens) pose an additive mortality threat to turtle eggs, juveniles, and, in some cases, adults. In this synthesis, I (1) review published and unpublished case studies of corvids as predators of chelonians, (2) examine regional population trends of corvids relative to the status of co-occurring chelonian species, and (3) evaluate our current understanding of subsidized corvids as threats to chelonians. Hyperpredation of chelonians by corvids is geographically widespread, locally severe where and when predation occurs, facilitated by anthropogenic subsidies (e.g., food, water, and perching, nesting, and roosting sites) and linear corridors (e.g., roads, electrical infrastructure), commonly associated with nesting corvids as predators, and co-occurring with corvid population increases. Hyperpredation by corvids appears to affect demographically sensitive stages of chelonian populations (juveniles and reproductive females) and very likely has long-term detrimental consequences given the slow life history of chelonians. The threat posed to chelonian populations by subsidized corvids is more widespread than currently recognized on the basis of substantial regional increases in corvid populations, the underreporting of predation observations, and the broad geographic areas over which hyperpredation of chelonians is occurring. [ABSTRACT FROM AUTHOR]

Threatened species throughout the world are in decline due to various causes. In some cases, predators of conservation or cultural value are causing the decline of threatened prey, presenting a conservation conundrum for managers. We surveyed marine turtle nests on K'gari (formally known as Fraser Island), Australia, to investigate dingo predation of green and loggerhead turtle nests, where each of these species is of conservation value. Our monitoring revealed that 84% of nests were predated by dingoes. Only 16% of nests were not consumed by dingoes, and only 5.7% of nests were confirmed to have successfully hatched. Up to 94% of nests were consumed in some areas, and predation rates were similar across different dingo packs. Information on the available numbers of nests and dingoes in the area indicated that turtle nests alone are sufficient to support extant dingoes over the summer. These results indicate that marine turtle eggs represent a previously unquantified but important food source for dingoes on K'gari, and that turtle nests at this rookery site are under serious threat from dingoes. This research should highlight the importance of prioritising the protection of turtle nests from dingoes or risk losing the entire rookery forever in the near future. [ABSTRACT FROM AUTHOR]

Sea Turtle Egg Fusariosis (STEF) is a worldwide emergent fungal disease affecting eggs and causing embryos mortality in turtle's nests such as those of Caretta caretta. It is caused by a complex of species belonging to Fusarium genus, particularly those included in the Fusarium Solani Species Complex (FSSC). During the samplings carried out in summer 2020 along the Tuscany coastlines (Italy), C. caretta eggs showed clinical signs resembling those caused by STEF. A total of 32 fungal isolates were obtained from lesioned eggs whose molecular characterization allowing identifying as belonging to FSSC / Neocosmospora spp., Fusarium oxysporum Species Complex (FOSC) / F. oxysporum and Fusarium nodosum , i.e., fungal genera and speciesincluding also well-known plant pathogens. Isolates inoculated on several plant hosts did not result in any pathogenic activity but F. nodosum causing, on wheat spikes, disease symptoms.This is the first time F. nodosum has been isolated from portions of eggs showing evident signs of fungal infection. This work represents the first report of Fusarium spp. isolated from C. caretta eggs showing lesions resembling those caused by STEF on Tuscan coast thus posing a significant concern to loggerhead sea turtle conservation also in this region. [Display omitted] • Fungal infectious diseases have dramatically increased in marine ecosystems. • STEF represent one of the main threats to Caretta in Mediterranean region. • A total of 32 strains of Fusarium strains were identified. • Phylogenetic relationships of Fusarium isolates have been reconstructed. • For the first time strains of F. nodosum were isolated from infected eggs. [ABSTRACT FROM AUTHOR]

Sea turtles are threatened with extinction around the world and rely on sandy beaches for laying their eggs. To protect eggs and locate them for calculation of reproductive success, beach surveyors must find the exact placement of each clutch. Eggs may be buried up to one meter deep under a nest mound several square meters in area. To locate sea turtle eggs, beach surveyors might spend hours searching for these eggs hidden in the sand, especially for difficult-to-locate leatherback (Dermochelys coriacea) and green turtle (Chelonia mydas) eggs. Scent-detection dogs (Canis lupus familiaris) are a novel tool that could provide a means to more accurately identify nests and efficiently locate eggs that need assessment, protection, or relocation. We assessed the effectiveness and feasibility of using a detection dog to locate sea turtle eggs buried in beach sand as compared to the traditional method using human beach surveyors. The detection dog was significantly more accurate in detecting loggerhead sea turtle (Caretta caretta) eggs and more efficient (less time spent and fewer holes dug) in assisting with locating the eggs. This case study presents results on the performance of one detection dog only, and additional research is needed with multiple detection dogs and handlers. [ABSTRACT FROM AUTHOR]

The echidna (Tachyglossus aculeatus) is documented as a new native predator of freshwater turtle eggs, particularly those of the vulnerable Fitzroy River turtle (Rheodytes leukops), and the critically endangered white-throated snapping turtle (Elseya albagula). This depredation has been identified in the Fitzroy, Burnett and Mary Catchments with echidnas recorded at traditional turtle nesting banks using direct observation of depredation of eggs, remote camera footage and identification of tracks. Echidnas were observed at traditional nesting banks for E. albagula and R. leukops nesting across eight months of the year. The presence of echidnas was more frequent during the R. leukops nesting season in spring. R. leukops is endemic to the Fitzroy Catchment and the depredation rate of eggs was significantly higher than for other species and catchments. The mean top egg depth of R. leukops nests was found to be the same depth as the echidna's beak length. There was a significant increase in depredation during the five-year study period, with 47.4% of R. leukops clutches depredated by echidna in the 2022 season. This substantial loss of eggs and recruitment of hatchling turtles poses a significant threat to the populations of this threatened species. The short-beaked echidna (Tachyglossus aculeatus) has been found to be an unlikely predator of freshwater turtle eggs. Egg depredation of the vulnerable Fitzroy River turtle (Rheodytes leukops) and the critically endangered white-throated snapping turtle (Elseya albagula) was recorded during annual freshwater turtle nesting surveys. The egg depredation by the echidna has been recorded across the Fitzroy, Burnett and Mary Catchments. Photograph by Duncan Limpus. [ABSTRACT FROM AUTHOR]

The article "Breeder Tricks" deals with the topic of microbiota and microbiome in relation to the care and breeding of turtles. It explains that the microbiome encompasses the entirety of all microorganisms in one place, while the microbiota refers to the entirety of all genes of these organisms. Although there is extensive scientific literature on this topic, there are currently no concrete applications of this knowledge in the care and breeding of animals. The article emphasizes the importance of the microbiome for animal reproduction and its impact on health. It is recommended to maintain a diverse community of microorganisms in the environment of turtles and to use appropriate filters. The effects of the external microbiome of turtles have not been sufficiently researched. It is noted that a biological balance in the terrarium is important and that a sterile environment can be problematic. Certain turtle species are sensitive to skin infections and require direct contact with plant roots. The microbiome in the intestinal tract of turtles plays an important role in digestion and nutrient absorption. It is recommended to enrich the diet with probiotic bacteria to improve the growth and immune system of turtles. The natural environment and the intake of microorganisms are crucial for the development and release of turtle hatchlings. When breeding, materials should be used that do not harm the young turtles. Pesticides and heavy metals can affect the microbiome and the development of embryos. Turtles usually automatically ingest microorganisms in natural habitats, while in indoor keeping, green fodder or live food from the garden or nature can be offered. Turtles selectively consume certain plants or animals to regulate their digestion. Carotenoids play a role in the microbiome, and a balanced diet is important. It is recommended to exchange information with other turtle breeders and veterinarians and consult further literature. The article contains a list of scientific publications on various aspects of the diet and microbiome of turtles. Studies on topics such as the rearing and diet of land turtles, the importance of the intestinal contents of feeder animals, and the role of freshly pupated insects in the diet of turtles are listed. Studies on the microbiota of turtle eggs and the impact of water quality on turtles are also discussed. The list also includes studies on other animal species such as alligator snapping turtles and Beal's eyed turtles. The list offers a variety of scientific articles and theses on various aspects of the care and maintenance of turtles. The articles cover topics such as the effects of environmental factors on the microbiota of turtles, the importance of diet for the health of turtles, and the effects of husbandry influences on the coloration of turtles. The articles come from different countries and cover different species of turtles. [Extracted from the article]

Hatching failure is one of the threats to the declining sea turtle population. Sea turtle egg fusariosis, an emerging fungal disease, has been linked to lower hatching success in sea turtle nests. The disease is associated with the presence of members of the Fusarium solani species complex (FSSC). Samples of cloacal mucus, nest sand, eggshells, and eggs were collected from seven hawksbill turtles and their corresponding nests at Melaka's nesting beaches and hatchery site. FSSC was prevalent in the unhatched eggs (n = 32) from the seven study nests, colonising 96.9%. The remaining eggs from the study nests were found to have high hatching success, with a mean of 85.8 ± 10.5% (n = 7). It is unknown if the presence of FSSC contributed directly to embryonic mortality in this study. There are two possible roles of FSSC in sea turtle eggs: as a saprophyte or a primary pathogen. The presence of FSSC in the nest did not always compromise the hatching success of the entire egg clutch. FSSC was not detected in the sand samples of all nests, even though all nests contained Fusarium-colonised eggs. The concentration of FSSC in the sand might influence the infection rate of sea turtle eggs and their hatching success. Best practices for hatchery must be in place to achieve high hatching success for sea turtle conservation. [ABSTRACT FROM AUTHOR]

The Chinese soft-shelled turtle, Pelodiscus sinensis, is an important aquaculture species in China that exhibits distinct sexual dimorphism; male individuals are economically more valuable than females. In vertebrates, several R-spondin family proteins have been associated with sex differentiation mechanisms; however, their involvement in P. sinensis sex differentiation is unclear. Exogenous hormones such as estradiol (E2) also influence the sex differentiation of P. sinensis and induce sexual reversal. In the present study, we investigated the effects of E2 on the embryonic development of P. sinensis and the expression of R-spondin 2 (Rspo2) and R-spondin 3 (Rspo3). We amplified P. sinensis Rspo2 and Rspo3 and analyzed their expression patterns in different tissues. Comparative analyses with protein sequences from other species elucidated that P. sinensis RSPO2 and RSPO3 sequences were conserved. Moreover, phylogenetic analysis revealed that P. sinensis RSPO2 and RSPO3 were closely related to these two proteins from other turtle species. Furthermore, Rspo2 and Rspo3 were highly expressed in the brain and gonads of adult turtles, with significantly higher expression in the ovaries than in the testes (p < 0.05). We also evaluated the expression of Rspo2 and Rspo3 after the administration of three concentrations of E2 (1.0, 5.0, and 10.0 mg/mL) to turtle eggs during embryonic development. The results revealed that E2 upregulated Rspo2 and Rspo3, and the expression trends varied during different embryonic developmental stages (stages 13–20). These findings lay the groundwork for future investigations into the molecular mechanisms involved in the sex differentiation of Chinese soft-shelled turtles. [ABSTRACT FROM AUTHOR]

The effects of transglutaminase (TGase), reductant, and thermal treatment on the cross-linking of white proteins in soft-shell turtle eggs were investigated. Egg white proteins were denatured by reductant (0.83% 2-mercaptoethanol, 2-ME) pretreatment and thermal pretreatment (95 °C and 5 min), and the denatured proteins were then catalyzed by TGase (1.0 unit/mL). SDS–PAGE showed that without any pretreatments, three major egg white proteins (210 kDa, 115 kDa, and 76 kDa proteins) were inferior substrates for TGase. Only portions of the 210 kDa protein (7.9%), 115 kDa protein (11.4%), and 76 kDa protein (42.9%) were polymerized by TGase into high-molecular-weight (MW) protein polymers (>180 kDa) after incubation for 3 h at 40 °C. However, the combined use of TGase with 0.83% 2-ME and thermal pretreatment led to a significant increase (p < 0.05) in the rate of white protein polymerization after 3 h: 210 kDa protein (90.8%), 115 kDa protein (69.5%), and 76 kDa protein (72.2%). Particle size analysis indicated that these cross-linked high-MW protein polymers were 2000–10,000 nm in size. Based on the experimental results, egg white proteins denatured by 2-ME and heat pretreatment are more prone to TGase-induced cross-linking. [ABSTRACT FROM AUTHOR]

Simple Summary: The western Mediterranean is an important nesting area for sea turtles, but at the same time, a hotspot for human-induced threats. Persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), as well as toxic and potentially toxic elements, are insidiously and ubiquitously distributed in the marine environment. These contaminants can accumulate in tissues, organs, and fluids of loggerhead turtle Caretta caretta, and maternal transfer of these chemicals via egg yolk during reproduction may affect the reproductive success of nesting populations. In this study, the levels of organochlorine pesticides, six indicator polychlorinated biphenyls, and trace elements were measured in unhatched eggs of C. caretta. With the exception of organochlorine pesticides, these contaminants were detected in all samples tested, demonstrating the transfer of chemicals from mothers to their progeny. However, their concentrations did not influence reproductive parameters. This study confirms the use of turtle eggs as a pollution monitoring tool and contributes to the scientific knowledge on the effects of environmental changes and human activities on sea turtle populations needed for the conservation of the species. Marine pollution is one of the major threats affecting loggerhead turtles, which due to their long life span, highly migratory behavior, and carnivorous diet, may be exposed to elevated levels of toxic elements throughout their life. The transfer of chemicals from mothers to their offspring is of particular conservation concern because it may affect embryonic development and hatching success. In this study, the concentrations of 16 toxic and potentially toxic trace elements, 6 indicator polychlorinated biphenyls (PCBs), and organochlorine pesticide residues (OCPs) were determined in 138 eggs from 46 loggerhead turtle nests laid during the 2021 nesting season in Campania, Italy, western Mediterranean Sea. The possible impact of pollutant levels on hatching success and early embryonic death was also investigated. Trace element analysis was performed using an ICP-MS, except for mercury, which was determined using a Direct Mercury Analyzer® (DMA). PCBs and OCPs were analyzed with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography tandem quadrupole mass spectrometry GC-MS /MS, respectively. The concentrations of essential elements in the eggs were higher than those of non-essential elements. In addition, the highly chlorinated PCBs (153, 138, and 180) contributed the most to the total PCBs, while OCPs were not detected. No correlations were found between contaminant concentrations and reproductive parameters (hatching success and no obvious embryos). The results obtained suggest that the levels of contaminants found in the eggs do not affect the reproductive success of the species in the study area. [ABSTRACT FROM AUTHOR]

Simple Summary: Habitat loss and nest predation significantly threaten European pond turtle (Emys orbicularis) populations. To reveal predation pressure in a protected area (Kis-Balaton marshland, Hungary) we conducted an artificial nests experiment. We used real nests which had been predated, and near each of them we created a new artificial nest. In each nest hole we put one quail egg, one plasticine egg and turtle egg shells and then covered them and sprayed the surface with water-diluted turtle urine. The majority of the nests were depredated in the first three nights, mostly by red foxes (Vulpes vulpes), confirmed by the bite marks preserved on the plasticine eggs, by footprints and excrements found near the nests and by camera recordings. Daily survival rates of quail eggs in artificial nests established in both real and in new nests were similar, suggesting that estimates obtained with artificial nests reflect the degree of predation pressure on real nests. Scattered nests had a lower survival rate than partly scattered and partly linear or only linearly arranged nests. We proved that spraying the nests with diluted turtle urine and marking them with a flag did not affect their survival. The results support turtle nest protection and selective predator control. Nest predation significantly impacts the population decline of the long-living European pond turtle (Emys orbicularis). Kis-Balaton is one of the most important habitats of this species in Hungary, and in May 2017 more than 400 damaged nests were counted. To reveal predation pressure, we conducted a study with artificial nests on three sites in this area. On each site, we used 11 depredated real nests, and near each of them, we created new artificial nests; then in every nest we put one quail egg, one plasticine egg and several turtle egg shells. After that, we sprayed the smoothed surface of the covered holes with water-diluted turtle urine, imitating the turtle's behaviour. Already in the first three nights, 94% of all nests were depredated by the red fox (Vulpes vulpes) and in one case by the European badger (Meles meles), which was confirmed by the bite marks preserved on the plasticine eggs, by the footprints and excrements found near the nests, as well as by camera recordings. Only 6% of the nests survived during the three weeks of our study. Daily survival rates of quail eggs in artificial nests established in both real (damaged) and in new nests were similar, suggesting that estimates obtained with artificial nests reflect the degree of predation pressure on real nests. On the site where the nests were scattered, their daily survival rate (33%) was significantly lower than on the sites where their arrangement was partly scattered, partly linear (83%), or only linear (76%). On two additional sites, by using simulated turtle nests we showed that spraying the nests with diluted turtle urine and marking them with a flag did not affect their survival, although further methodological testing is needed. The information obtained with artificial nests enables the organization of the protection of the nests of the European pond turtle and selective predator control. [ABSTRACT FROM AUTHOR]

A recent study challenges the traditional view of early dinosaur eggs as soft-shelled, suggesting that they were actually leathery-shelled, similar to some turtle eggs. The protective egg is crucial for the success of dinosaurs, reptiles, and birds. The study presents evidence from the nest of an Early Jurassic sauropodomorph, which contains leathery eggs. This discovery suggests that the first amniotic egg, which allowed reptiles to lay eggs on land, was likely leathery rather than hard-shelled. The study also includes information about the dinosaur skeletons, nests, and embryos found in the Ziliujing Formation of Guizhou Province. [Extracted from the article]

The article titled "Turtles as Prey of Crested Caracaras (Caracara plancus) on the Katy Prairie, Texas" discusses the diet of Crested Caracaras, a bird species that consumes a variety of foods including turtles. The authors observed a pair of adult caracaras carrying small turtles to their fledglings in a specific location on the Katy Prairie in Texas. They found numerous small turtle carcasses beneath a sugarberry tree, indicating that caracaras regularly prey on turtles. This observation raises conservation concerns, particularly for the western chicken turtle, a subspecies that is under threat from urbanization in Texas. Further study is needed to determine the impact of caracara predation on western chicken turtles in the area. [Extracted from the article]

The olive ridley sea turtle Lepidochelys olivacea is the most abundant marine turtle species in Guatemala, representing > 99% of all nests. Along with other marine turtles, they are important both culturally and ecologically. Conservation efforts rely almost exclusively on an informal system whereby local residents can harvest olive ridley sea turtle nests on the condition they donate 20% of each nest to a hatchery, where the eggs are incubated and hatchlings later released. This system was initiated in the 1970s and, until recently, no effort has been made to determine its sustainability. In a 2020 publication based on tracks on a single beach in Guatemala and 15 years of egg incubation data from Guatemalan hatcheries, it was concluded that the population had increased. Several weaknesses were detected in this research. To verify the validity of the conclusion, we analysed data from 22 years (2 years are missing) and 11 beaches using several statistical models. We used an intraseasonal model of nesting phenology to fill in missing data for monitored periods during a nesting season, and a new method of spatial and temporal aggregation of nesting seasons. Based on our findings, we reject the hypothesis that olive ridley sea turtle nesting activity is increasing. The total nesting activity for these 12 beaches was stable over the 22-year period. Because of inconsistent hatchery management and the financial dependency of local communities on the sale of turtle eggs, the number of incubated eggs cannot be used as an indicator of the population trend of olive ridley sea turtles in Guatemala. [ABSTRACT FROM AUTHOR]

Predation of nests and hatchlings can significantly reduce sea turtle reproductive output. On Cavalos island, João Vieira and Poilão Marine National Park, Bijagos archipelago, Guinea-Bissau, one of the primary threats to green turtle nests is predation by Nile monitors (Varanus niloticus). In this study, we tested 3 different nest protection techniques—disguising scent cues, disguising visual cues, and placing a metal net over the nest—to reduce predation on green turtle (Chelonia mydas) nests by Nile monitors. Nests were monitored for 10 d after they were laid, and we found that using metal nets and disguising scent cues led to a significant increase of the number of days it took for Nile monitors to find and predate the nests. Overall reduction in predation rates also approached significance when metal nets or disguising scent cues were used. We used the Risk Reduction metric to compare the effectiveness of our experiment with other nest protection techniques; our results corresponded to a > 50% decrease in the risk of predation, a value comparable to or better than other techniques used elsewhere. We suggest that camouflaging a nest's scent may be the most cost-efficient management option to reduce predation rates by Nile monitors in sensitive areas without damaging the local ecosystem. [ABSTRACT FROM AUTHOR]

Testudines is a reptilian order characterized by low annual recruitment and delayed sexual maturity. One testudine species of conservation concern is the Rio Grande cooter (Pseudemys gorzugi), a taxon native to the southwestern United States and the westernmost species in this genus. A clear understanding of the reproductive biology of turtle species in the wild better informs conservation management options. The reproductive biology of P. gorzugi has been formerly investigated in the Black River of southeastern New Mexico. Because life history strategies of chelonian taxa may vary across geographic gradients, we examined the reproductive biology of this species at 3 sites in west Texas from 2017 to 2019. We detected follicle enlargement beginning in the fall with shelled eggs appearing as early as 7 April and as late as 12 August. We found a significant quadratic relationship between day of year and maximum follicle diameter (r2 = 0.22, F2,100 = 15.61; p < 0.05). A significant relationship between turtle size and clutch size was not detected nor was there a significant relationship between turtle size and egg width. We detected a record clutch size of 17 eggs and a mean ± SD clutch size of 11.4 ± 3.11. We observed a single instance of production of 2 clutches. The smallest gravid female we detected with shelled eggs had a plastron length of 179 mm. We also found that the probability of capturing a female gravid with shelled eggs was highest in early June. Our results suggest geographic variation occurs in the reproductive biology of P. gorzugi and highlight the importance of range-wide, temporally extensive sampling. Data presented herein can be included in population viability assessments and inform conservation recovery plans. Testudines es un orden de reptiles caracterizado por un bajo reclutamiento anual y una madurez sexual tardía. Una especie testudina de interés para la conservación es la tortuga del Río Grande (Pseudemys gorzugi), un taxón nativo del suroeste de los Estados Unidos y la especie más occidental de este género. Una comprensión clara de la biología reproductiva de las especies de tortugas en la naturaleza brinda mejor información a las opciones de manejo y conservación. La biología reproductiva de P. gorzugi se ha investigado anteriormente en el Río Negro del sureste de Nuevo México. Debido a que las estrategias de historia de vida de los taxones de quelonios pueden variar según los gradientes geográficos, examinamos la biología reproductiva de esta especie en tres sitios en el oeste de Texas entre el 2017 y 2019. Detectamos el agrandamiento del folículo a partir del otoño con la aparición de huevos sin cáscara desde el 7 de abril y tan tarde como el 12 de agosto. Encontramos una relación cuadrática significativa entre el día del año y el diámetro máximo del folículo (r2 = 0.22, F2,100 = 15.61; p < 0.05). No se detectó una relación significativa entre el tamaño de la tortuga y el tamaño de la nidada ni hubo una relación significativa entre el tamaño de la tortuga y el ancho del huevo. Detectamos un tamaño récord de nidada de 17 huevos y un tamaño medio ± DE de nidada de 11.4 ± 3.11. Observamos un solo caso de producción de dos nidadas. La hembra grávida más pequeña que detectamos con huevos sin cáscara tenía una longitud de plastrón de 179 mm. También encontramos que la probabilidad de capturar una hembra grávida con huevos sin cáscara era más alta a principios de junio. Nuestros resultados sugieren que se produce una variación geográfica en la biología reproductiva de P. gorzugi y resaltan la importancia del muestreo extenso temporal en todo el rango. Los datos presentados en este documento pueden incluirse en las evaluaciones de viabilidad de la población e informar los planes de recuperación y conservación. [ABSTRACT FROM AUTHOR]

Peptides derived from egg protein hydrolysate have potential hypoglycemic benefits by inhibiting α‐glucosidase. Herein, fluorescence spectroscopy and molecular docking were performed to investigate the α‐glucosidase inhibitory mechanism of the oligopeptides ARDASVLK and HNKPEVEVR from soft‐shelled turtle eggs. Gastrointestinal digestion characteristics of the two oligopeptides were further determined by LC‐QTOF‐MS/MS. The static fluorescence quenching of α‐glucosidase by ARDASVLK and HNKPEVEVR indicated the formation of a stable α‐glucosidase‐peptide complex, mainly driven by hydrogen bonds and hydrophobic interactions. ARDASVLK and HNKPEVEVR could easily insert into the active pocket of α‐glucosidase (docking scores of −157.1 and −158.4, respectively), thereby inhibiting enzyme activity by preventing substrate binding and inducing enzymatic conformation change. After gastrointestinal digestion, 14.3% and 30.4% of ARDASVLK and HNKPEVEVR were maintained intact, respectively, and their digestive products (mainly DASVLK and HNKPEVEV) still showed high inhibitory effects on α‐glucosidase (about 35% inhibition). This study sheds light on the mechanism of oligopeptides derived from soft‐shelled turtle eggs as a novel α‐glucosidase inhibitor for diabetes. Practical applications: Oligopeptides from egg protein hydrolysate have potential hypoglycemic properties by inhibiting α‐glucosidase. This study has provided insights into the inhibitory mechanism of oligopeptides from soft‐shelled turtle egg on α‐glucosidase. Interestingly, despite the fact that the oligopeptides are largely degraded during gastrointestinal digestion, their digestive metabolites displayed strong α‐glucosidase inhibitory activities. Because α‐glucosidase is highly expressed in small intestine brush border, our findings support the possibility of these oligopeptides as an attractive health‐benefit compound to control glucose without being absorbed by intestinal epithelial cells, unlike other enzyme inhibitors such as ACE inhibitors, which have poor oral bioavailability. This study may facilitate the applications of oligopeptides from soft‐shelled turtle egg as α‐glucosidase inhibitors and food functional ingredients for the therapy of diabetes. [ABSTRACT FROM AUTHOR]

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During the last few decades, fungal pathogens have caused devastating population declines across a broad range of taxa. A newly emerging fungal disease, sea turtle egg fusariosis, caused by members of the Fusarium solani species complex (FSSC), has been reported to be responsible for hatching failure in sea turtles worldwide. However, this has not been detected in fresh water turtle species. Here, using relocated clutches and artificial incubation, we report high hatching failure in eggs symptomatic of fusariosis in the yellow‐spotted Amazon River turtle (Podocnemis unifilis) inhabiting a pristine environment in the Ecuadorian Amazon. In 2020, we screened 680 eggs of the yellow‐spotted Amazon River turtle, relocated from wild nesting areas to artificial nests, for visual symptoms of fusariosis and to estimate hatchability despite infection. We selected 68 eggs sampled in 2019 to confirm Fusarium infection by PCR amplification of the TEF‐1α gene and sequenced seven of those amplicons on an Illumina Miseq to assess FSSC membership. We observed fusariosis symptoms in 42% of the 680 eggs. The proportion of symptomatic eggs within nests was negatively linked to the proportion of eggs that hatched. Hatchability was 8% for symptomatic eggs compared with 72% of asymptomatic eggs. Through PCR testing, 58% of symptomatic and 8% of asymptomatic eggs sampled in 2019 tested positive for Fusarium spp., and sequencing revealed that nine sequence variants from three asymptomatic and four symptomatic eggs corresponded to F. keratoplasticum, F. solani and F. falciforme, the three major FSSC pathogens reported in sea turtle egg fusariosis. Our study suggests that hatching failure in eggs linked to symptoms of fusariosis appears to be partially caused by Fusarium pathogens within FSSC in a freshwater turtle. Thus, fusariosis is more widespread among the Testudines than previously reported and is not limited to sea environments, findings of particular conservation concern. [ABSTRACT FROM AUTHOR]

Knowledge of the abundance and distribution of species is important for designing and prioritizing conservation and management activities. Despite numerous existing studies on the distribution and status of sea turtles, we still lack knowledge about certain populations, especially in Angola, which is considered to be the southernmost range of nesting sea turtles in the eastern Atlantic. This study provides an overview of the status, size and distribution of the olive ridley sea turtle Lepidochelys olivacea population nesting along the coast of Angola, and its relevance in the context of other olive ridley turtle nesting populations in the Atlantic. Aerial and ground surveys were conducted along 1,410 km of Angolan coastline and daily beach monitoring over 53.9 km of seven permanent study sites at a range of latitudes during 2011–2020. Angola hosts the largest olive ridley turtle nesting population in the Atlantic, and the largest non-arribada population globally. Although the population appeared relatively stable, the pressures from various threats on land (e.g. consumption of turtles and eggs) and at sea (captures in fishing gear) necessitate the development of a comprehensive management plan, improved and strengthened legislation and law enforcement, and a cohesive approach to conserving all sea turtle species in Angola. [ABSTRACT FROM AUTHOR]