Search Results (43)

Parasites are increasingly recognized as indicators of ecosystem condition, in part, because the relative complexity of their life cycles relies on ecosystem stability over time. Haemogregarine infections in freshwater turtles are rarely reported as an assessment of freshwater ecosystems, despite these parasites being nearly ubiquitous and sensitive to environmental context. This study investigated haemogregarine infection prevalence and relative abundance of haemogregarine DNA in blood samples from multiple turtle species and across several aquatic ecosystems in Texas and New Mexico, USA. We evaluated associations with host species, river system, anthropogenically modified flow condition, and urbanization context from quantitative PCR results and statistical modeling. Host species was the most consistent predictor of infection patterns, with Trachemys scripta elegans exhibiting the highest observed infection prevalence and relative parasite DNA abundance, whereas Pseudemys gorzugi exhibited the lowest values. After accounting for host species, infection prevalence differed among river systems, and turtles from anthropogenically created low-flow or flow-modified habitats had lower infection odds than those from flowing habitats. Although observed infection prevalence was higher at sites classified as urban, this association was reversed after accounting for host species composition and flow condition, highlighting substantial confounding caused by uneven species representation across environments. Among qPCR-positive individuals, host species remained significantly associated with relative parasite DNA abundance, whereas flow condition and urban status provided only a slight reduction in unexplained variation. Relative carapace length was associated with infection prevalence among adults, whereas sex and standardized body mass were not. The results indicate that host species and environmental context contribute differently to haemogregarine infection dynamics and emphasize the importance of accounting for host-community composition when evaluating environmental effects. Full article

The spread of non-native freshwater turtles in urban, peri-urban, and natural environments poses increasing ecological and sanitary concerns, particularly due to their potential role as reservoirs of infectious agents. Among these, DNA viruses remain largely unexplored in both invasive and native chelonians. In this study, a molecular survey targeting selected viral pathogens was conducted on oral and cloacal swabs collected from non-native freshwater turtles from natural and confinement ponds in Northeastern Italy, with the aim of assessing the pathogen’s presence and their potential epidemiological relevance. One hundred sixty-four pond sliders (Trachemys scripta) were sampled from three sites: Herpesviruses and ranaviruses were not detected; in contrast, adenoviruses were frequently identified (72/163, 44.2%). Sequence analyses allowed their classification mostly as Testadenovirus trachemys, with only a single detection of a strain closely related to siadenoviruses and previously associated with mortality events in other tortoise species. Although the pathogenic significance of these viruses remains unclear, their detection highlights the potential role of non-native turtles as viral carriers and underlines the need for systematic virological surveillance in non-native species, particularly in ecosystems shared with susceptible native fauna. Full article

Background/Objectives: The IUCN endangered spotted pond turtle (Geoclemys hamiltonii) demonstrates markedly reduced resistance to Aeromonas hydrophila-induced infections compared to the red-eared slider (Trachemys scripta). This study investigates the immunological basis for this disparity by analyzing infection outcomes and splenic transcriptomes of both species post-pathogen challenge. Methods: In a preliminary experiment, 32 turtles (16 G. hamiltonii and 16 T. scripta) were exposed to A. hydrophila. Results: G. hamiltonii developed skin ulcer syndrome at a significantly higher incidence (81.25%) than T. scripta (12.5%) (p < 0.05). Comparative transcriptomic analysis identified 19 differentially expressed immune-related genes, with qPCR validation across five tissues (heart, liver, spleen, intestine, blood) revealing pronounced interspecies differences in IL18, STAT1, IFIH1, and CD28 expression. Notably, IL18 and its downstream effector STAT1 were robustly upregulated in T. scripta but were considerably lower in G. hamiltonii, correlating with delayed IFN-γ pathway activation and impaired epidermal barrier repair. Concurrently, CD28 upregulation in T. scripta facilitated rapid T-cell-mediated pathogen clearance, whereas its delayed induction in G. hamiltonii hindered adaptive immunity. These findings implicate dysregulated innate (IL18/STAT1) and adaptive (CD28) immune pathways as key determinants of G. hamiltonii’s susceptibility to bacterial infection. Conclusions: Despite the critical conservation status of G. hamiltonii, the immunological basis underlying its heightened susceptibility to bacterial infections remains largely unexplored; this study addresses this gap by comparing the splenic transcriptomes of G. hamiltonii and T. scripta following A. hydrophila challenge, identifying the dysregulated IL18-STAT1 Immune Axis and CD28-mediated adaptive immunity as key determinants, thereby providing actionable immune targets for conservation breeding and susceptibility screening in this endangered species. Full article

Mammals and reptiles possess a metanephric kidney as the terminal renal organ for homeostasis of solutes and waste products. The development of the metanephric kidney has primarily been studied in mammalian model systems. Little is known about the conservation of metanephric kidney formation in non-mammalian species such as reptiles. Uniquely, reptiles maintain kidney progenitor cell populations throughout life and continually develop new nephrons, the functional unit of the kidney. The red-eared slider turtle, Trachemys scripta elegans, was utilized to investigate the conservation of reptilian metanephric kidney development. The nephron progenitor cell (NPC) marker, Six2, was detected in whole-mount turtle kidneys in a similar pattern to mammals. However, there were differences in progenitor cell niche morphology where turtle NPC populations formed distinct elongated rows instead of the rosette-like morphology found in the mouse. The pattern of NPC populations in the embryonic turtle kidney was maintained in the adult turtle. Whole-genome bisulfite sequencing was performed on cortical tissue containing the NPC populations from adult turtle kidneys and compared to those of adult mice. Significant conservation of gene methylation was detected in adult cortical tissue between the two species, although unique signatures were detected in turtle samples related to DNA repair and β-catenin signaling. This suggests a high level of conservation of metanephric kidney development at the genetic level. Full article

Understanding the ecological behavior of invasive species is essential for assessing their impacts on native biodiversity. This study examines the basking dynamics of the invasive freshwater turtle Trachemys scripta in a Mediterranean wetland within Mesir Nature Park, Türkiye. Data were collected between March and October 2024 using camera traps, yielding 72,456 cumulative basking observations. Principal Component Analysis (PCA) revealed a high degree of environmental synchronization (PC1 = 97.24%), indicating that basking activity is strictly governed by ambient thermal availability. Furthermore, Negative Binomial Regression (NBR) was employed to evaluate temporal shifts and behavioral plasticity. The basking intensity exhibited distinct seasonal transitions, characterized by afternoon peaks during the spring and autumn and an opportunistic shift toward early morning activity during the summer to mitigate thermal constraints. The peak basking duration recorded in May (696.00 ± 10.25 min) and the bimodal activity observed in summer reflect a significant adaptive capacity. These patterns suggest that Mediterranean wetlands provide optimal conditions for the persistence of Trachemys scripta. The species’ ability to effectively track environmental cues and monopolize thermal resources implies a high potential for the ecological displacement of native turtles, particularly Mauremys rivulata. This study provides critical quantitative baseline data in order to inform evidence-based management and control strategies in the Mediterranean region. Full article

Due to the relatively long lifespan and resilience of adults to environmental stressors, freshwater turtles are characterized as bioaccumulators of chronic contaminant exposure in urban ecosystems. Urbanization increases pollutants, resulting in subsequent runoff into streams. We evaluated the relationship between percent impervious surface and contaminant concentrations in turtles from 20 wetlands in Wake County, North Carolina, USA, one of the fastest-growing counties in the United States. We evaluated the concentrations of eight environmental contaminants known to cause human and environmental health issues listed under the U.S. Environmental Protection Agency’s Resource Conservation and Recovery Act: arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), selenium (Se), and silver (Ag), as well as vanadium (V) and copper (Cu) due to their presence in urban environments and bioaccumulation, in the blood and claws from Chelydra serpentina and Trachemys scripta. All contaminants, except for Cd and Ag, were detected in both species and both tissue types. Carnivorous Chelydra serpentina exhibited higher concentrations of Se and Hg than omnivorous Trachemys scripta. Partial redundancy analysis indicated that species accounted for more variance in the data than % impervious surface at a 2200-m scale. Robust mixed-effects models showed that % impervious surface was not correlated with contaminant concentrations in either species. Although we documented no relationship between urbanization and contaminant concentrations, we recommend additional research to investigate the effects of urbanization over time in this rapidly developing region. Full article

Biological invasion is a major driver of biodiversity loss and ecosystem disruption, with non-native aquatic species threatening ecological integrity and economic stability. The Qinling Mountains, located in central China, serve as a crucial barrier between temperate and subtropical climate zones, and separate the Yellow and Yangtze River basins. This study investigates the role of these geographical barriers in regulating the distribution and invasion risk of non-native aquatic species. We identified 27 non-native species in Shaanxi Province based on occurrence records compiled from field survey conducted between 2012 and 2024 (and from 2019 to 2024 in the Yellow River mainstream of the Shanxi–Shaanxi Gorge), including 13 high-risk species, such as Trachemys scripta elegans, Procambarus clarkii, Sander lucioperca, and Hypomesus olidus. Using the Aquatic Species Invasiveness Screening Kit and species distribution models, we identified the Hanjiang River in the Yangtze basin and Weihe River estuary in the Yellow River basin as high-risk areas for these species. Mean annual temperature was the primary environmental factor influencing species distribution, with species adapted to cooler conditions predominantly found north of the Qinling Mountains, while those preferring warmer climates are more common in the south. Our findings highlight the Qinling Mountains as both a physical and climatic barrier, limiting cross-basin dispersal and creating distinct invasion patterns. However, human activities such as inter-basin water-transfer projects, damming, and aquaculture practices have gradually weakened the barrier’s effectiveness, facilitating the spread of invasive species. We recommend prioritizing monitoring efforts in cross-basin water-transfer regions, focusing on high-risk species adapted to both cooler and warmer climates, and incorporating environmental DNA (eDNA)-based monitoring in recipient areas of inter-basin water-transfer projects for early detection and control to minimize ecosystem damage. Full article

The pond slider (Trachemys scripta) is native to the southeastern United States but has been introduced all around the world, including to the Canary Islands (Spain), along with other less-common exotic freshwater turtles such as Graptemys pseudogeographica, Mauremys spp., and Pseudemys peninsularis. The aim of this study was to determine the presence of pathogenic bacteria in these animals and to evaluate the associated health risks for humans and local fauna. For this purpose, cloacal samples from 42 specimens collected on the islands of Tenerife and Gran Canaria (Canary Islands) were analyzed for potentially zoonotic bacteria using selective culture media and PCR. Non-tuberculous mycobacteria were the most isolated pathogen (57.9%), followed by Yersinia enterocolitica (42.1%) and Escherichia coli carrying stx and/or eae genes (33.3%). Salmonella spp. was detected in 31.0% of the chelonians, identifying Salmonella Typhi and Salmonella Typhimurium serotypes. Staphylococcus spp. showed a prevalence of 21%, mainly Staphylococcus aureus along with one antibiotic-resistant Staphylococcus hominis isolate. Pseudomonas spp. were found in 10.1% of samples, although only one isolate corresponded to Pseudomonas aeruginosa. Campylobacter spp. and Vibrio spp. were detected at low frequencies (<10%), and Listeria monocytogenes was not identified. Overall, the results indicate that aquatic turtle populations in the Canary Islands pose notable health risks, especially for animal handlers and people with compromised immune systems. Full article

The popularity of exotic animals, including turtles, kept as pets, has grown steadily in recent decades. Limited awareness of the biological and ecological requirements of these species, combined with insufficient regulation in the pet trade, has contributed to frequent cases of release into the wild. Consequently, the risk of the introduction of non-native turtle species has increased; while not all introduced species establish viable populations or compete with native fauna, some compete for habitat and food resources, transmit pathogens and parasites, or disrupt ecosystem functioning. This study assessed the availability and prevalence of problematic turtle species in the Polish pet trade. Data were collected in 2024 from three main distribution channels: zoological fairs, pet shops, and online platforms, resulting in 1001 recorded observations. A total of 15 freshwater and 11 terrestrial turtle species were identified. The most frequently offered were members of the genus Pseudemys (49.5%) and Mauremys reevesii (13.84%)—both potentially invasive taxa already recorded in natural environments of several European countries. Additionally, species prohibited from trade in Poland, such as the pond slider Trachemys scripta and the false map turtle Graptemys pseudogeographica, were found among online listings, constituting a total of 3.03% of all observations. These results highlight a significant risk of further introduction of alien turtles into Poland’s natural environments, posing a serious threat to biodiversity, including the endangered native European pond turtle Emys orbicularis. Urgent public education and additional legal regulations are needed for the pet trade to prevent the further spread of invasive turtle species in Poland and across Europe. Full article

Illegal wildlife trade is a major global driver of biodiversity loss, shaped by high consumer demand, transboundary networks, and uneven enforcement. In the Middle East, particularly the Gulf Cooperation Council (GCC) region, factors such as high purchasing power, cultural traditions (e.g., falconry, prestige pets), and expanding digital marketplaces sustain both legal and illegal flows. We present a nine-year (2017–2025) assessment based on weekly, repeated field surveys at the Friday Market, adjacent pet shops, and private farms, complemented by systematic monitoring of online advertisements on Haraj.com.sa. We recorded 1063 individual animals across 88 species, birds (39.4%), reptiles (52.0%), and mammals (8.6%), and analyzed prices, conservation status, and venue-specific patterns. The most frequently recorded taxa included the white-eared bulbul (Pycnonotus leucotis), common slider (Trachemys scripta), and Egyptian mastigure (Uromastyx aegyptia). Mammals, though fewer in number, commanded the highest prices, particularly cheetahs (Acinonyx jubatus) and lions (Panthera leo). About 26% of species were IUCN-listed as threatened, with CITES Appendix I taxa fetching higher prices. Findings underscore the need for real-time monitoring, targeted enforcement, and cross-border collaboration to address escalating trade in rare and protected species. Full article

Vitamin A deficiency is common in pond sliders, and vitamin E and B1 deficiencies have also been described in carnivorous aquatic species such as crocodiles, but otherwise little is known about vitamin concentrations in the blood of reptiles, and reference intervals only exist for a few vitamins in a few species. The aim of this study was therefore to measure vitamins A, B1, B2, B6, B9, B12, and E in the heparinized whole blood and plasma of pond sliders (Trachemys scripta) (n = 188) from April to September 2022 using high-performance liquid chromatography (HPLC) and spectrophotometry. In addition to establishing reference intervals, possible influencing factors, including the season of blood sampling and the sex of the turtles, were evaluated. The median concentrations measured were as follows: vitamin A—0.17 mg/L, B1—59.10 µg/L, B2—693.50 µg/L, B6—2.375 µg/L, B9—16.06 ng/mL, B12—3225.00 pg/mL, and E—7.59 mg/L. Significant (p ≤ 0.05) seasonal variations were found for vitamin A, B1, and B9, and sex-specific variations were found for vitamin E. The results show that factors such as sex and the time of year play a role in vitamin levels in the blood of turtles and should be considered when interpreting blood results. The reference intervals established in the present study serve as a basis for further studies and help to control and improve the vitamin supply of the turtles, contributing to the better husbandry and nutrition of this species in human care. Full article

The fungal pathogens Fusarium keratoplasticum and Fusarium falciforme are responsible for the emerging infectious disease named sea turtle egg fusariosis (STEF). This disease affects all sea turtle species throughout the world, causing low hatching success and mass mortalities. In this study, we investigated the potential use of widely available and easy-to-handle eggs of the invasive alien red-eared slider turtle, Trachemys scripta, as part of an in vivo host model to improve our knowledge of the biological properties of the pathogens responsible of the STEF. Specifically, we performed in vivo experiments, in which T. scripta eggs were challenged with conidia of F. keratoplasticum isolated from diseased sea turtle eggs. We found that the pathogen could colonize and develop similar signs to those observed in nature and fulfill Koch’s postulates. The pathogen showed high virulence properties (e.g., high disease incidence, severity, and low hatching success) and its ability to modify the pH in both the egg surface and culture media, confirming previously described fungal pathogen models. These results support the use of T. scripta as an experimental in vivo host model for studying the biological characteristics of STEF, thus providing valuable insights into the mechanisms underlying the emergence of this fungal disease. Full article

Investigating the physiological and biochemical changes of ectothermic species before entering hibernation would contribute to the understanding of how they adapt to low-temperature environments. Here, red-eared slider turtle (Trachemys scripta elegans) hatchlings were maintained under different thermal treatments (24 °C, slowly decreasing temperatures from 24 °C to 14 °C, and to 4 °C). Hepatic metabolite alterations were measured to assess the metabolic impacts of low-temperature stress in this species. Of these differentially changed metabolites, some (e.g., raffinose, spermidine, allocholic acid, taurohyocholate, 2-ketobutyric acid, acetylcysteine) were shown to decrease, while others (e.g., stearolic acid, D-mannose) increased in low-temperature treatments. Our results indicated that short-term low-temperature stress might have limited impacts on lipid and energy metabolism in this species. The changes in other metabolites (e.g., allocholic acid, taurohyocholate, spermine, acetylcysteine) might be associated with a low food intake (and thus reduced digestive performance) and weakened immune ability of low-temperature-exposed animals. Full article

Animal personalities play a crucial role in invasion dynamics. During the invasion process, the behavioral strategies of native species vary among personalities, just as the invasive species exhibit variations in behavior strategies across personalities. However, the impact of personality interactions between native species and invasive species on behavior and growth are rarely illustrated. The red-eared slider turtle (Trachemys scripta elegans) is one of the worst invasive species in the world, threatening the ecology and fitness of many freshwater turtles globally. The Chinese pond turtle (Mauremys reevesii) is one of the freshwater turtles most threatened by T. scripta elegans in China. In this study, we used T. scripta elegans and M. reevesii to investigate how the personality combinations of native and invasive turtles would impact the foraging strategy and growth of both species during the invasion process. We found that M. reevesii exhibited bolder and more exploratory personalities than T. scripta elegans. The foraging strategy of M. reevesii was mainly affected by the personality of T. scripta elegans, while the foraging strategy of T. scripta elegans was influenced by both their own personality and personalities of M. reevesii. Additionally, we did not find that the personality combination would affect the growth of either T. scripta elegans or M. reevesii. Differences in foraging strategy may be due to the dominance of invasive species and variations in the superficial exploration and thorough exploitation foraging strategies related to personalities. The lack of difference in growth may be due to the energy allocation trade-offs between personalities or be masked by the slow growth rate of turtles. Overall, our results reveal the mechanisms of personality interaction effects on the short-term foraging strategies of both native and invasive species during the invasion process. They provide empirical evidence to understand the effects of personality on invasion dynamics, which is beneficial for enhancing comprehension understanding of the personality effects on ecological interactions and invasion biology. Full article

Freshwater acidification (FA) has become a global environmental problem, posing a potential threat to freshwater ecosystems. The gut microbiota plays a crucial role in the host’s response and adaptation to new environments. In this study, we investigated the changes in microbial communities in Red-eared slider (Trachemys scripta elegans) under acidic conditions to reveal the ecological impacts of acidification on freshwater turtles. The results showed that there were significant differences in β-diversity (p = 0.03), while there were no significant differences in the α-diversity of gut microbiota in T. s. elegans between the different levels of acidification (pH of 5.5, 6.5, 7.5). Both the Gut Microbiome Health Index (GMHI) and the Microbial Dysbiosis Index (MDI) exhibited significant differences when comparing environments with a pH of 5.5 to those with a pH of 6.5 (p < 0.01). A comparative analysis between pH levels of 5.5 and 6.5 also revealed substantial differences (p < 0.01). Likewise, a comparative analysis between pH levels of 6.5 and 7.5 also revealed substantial differences (p < 0.01). At the phylum level, Firmicutes, Fusobacteria, and Bacteroidota formed a major part of the gut microbial community, Fusobacteria showed significant differences in different acidity environments (p = 0.03). At the genus level, Cetobacterium, Turicibacter, unclassified Eubacteriaceae, and Anaerorhabdus_furcosa_group showed significant differences in different acidity environments. The pH reduced interactivity in the gut microbiota of T. s. elegans. In addition, LEfSe analysis and functional prediction revealed that the potentially_pathogenic and stress_tolerant functional characteristics also showed significant differences in different acidity environments. The findings underscore the pivotal role of the gut microbiota in T. s. elegans in response to freshwater acidification and provide a foundation for further exploration into the impacts of acidification on freshwater ecosystems. Full article