Integrative zoology最新文献

Oxygen is a critical factor for the survival of most lifeforms, as inadequate availability disrupts internal metabolic balance. Hypoxia-induced disruptions in glucose metabolism can be fatal to many animals. However, there is currently limited research on the energy metabolism of species that inhabit environments with intermittently low oxygen levels. In this study, we investigated the gluconeogenic metabolic response patterns of adult Lasiopodomys brandtii (Brandt's vole) and Mus musculus (Kunming mice) under hypoxia (10% O₂, 12 h), followed by 1 h reoxygenation period. Our results indicated that, unlike M. musculus, L. brandtii did not accumulate lactate after hypoxia treatment. This suggests that L. brandtii may deal with lactate accumulation caused by oxygen deficiency during hypoxia through the PGC-1α regulated gluconeogenesis pathway of the liver, which can restore the level of anaerobic glycolytic products in the liver and blood caused by hypoxia relatively quickly and ensure the stable survival of the organism in a hypoxic environment. Intriguingly, L. brandtii also did not exhibit O₂ debt repayment after short-time reoxygenation. Our study revealed that liver PGC-1α regulating gluconeogenic metabolism in L. brandtii plays an important role in the maintenance of internal homeostasis of body acid-base balance under hypoxic environments, presenting a potential mechanism for the improvement of hypoxia tolerance in L. brandtii.

Sperm transfer constraints are common phenomena in spider mating systems, influenced by both behavioral and morphological factors. Non-motile, encapsulated sperm cells must navigate through narrow male and female ducts during short (only seconds) copulations, all while under the pressure of female aggression, which can include sexual cannibalism and genital damage. However, little attention has been paid to the impact of male and female internal genital morphology on sperm transfer. In this study, we quantify the number of sperm transferred by males in five species of the genus Argiope as a direct measure of reproductive success. We explore sperm transfer in relation to copulation duration, sperm availability, sexual dimorphism, and female aggression. Additionally, we compare intra- and interspecific variation in sperm transfer by examining internal male and female genital morphological traits. Finally, we discuss the allometry of internal genital morphology in terms of sperm transfer in spiders. Our findings indicate that the occurrence of sexual cannibalism is the significant factor impacting sperm transfer in the genus Argiope. We observed a positive, albeit non-significant, correlation between sperm duct width and sperm transfer. Nonetheless, interspecific variability in allometry and methodological challenges underscore the need for continued research to fully understand the complexities of internal genital evolution in spiders.

The study of animals' activity and behavior in the wild is an extremely challenging task. Although tri-axial accelerometers are invaluable for behavioral analyses, their use is more frequent in large charismatic endotherms with limited application in ectotherms. The scarce utilization of this methodology on small-size reptiles is focused on animals' activity and energetics, showing few records of rapid displays and behavior signals. Here, we present a novel multidisciplinary approach capable of advancing research on reptiles' behavior. Our proposed approach uses advanced technologies for the digitization, reconstruction and visualization of reptiles and their behavior. We (i) record movement through tri-axial accelerometers, video cameras, and motion capture systems; (ii) ground-truth data through the video records; (iii) develop realistically accurate 3D avatars of the recorded movement for visualization purposes, and (iv) archive data on a Behavior Pattern Database. As case studies, we used two small Mediterranean reptiles, the lizard Laudakia cypriaca and the snake Dolichophis jugularis. Through our approach, we successfully recorded, ground-truthed, and labeled for the first time, several detailed movements and behaviors of the two case study species. We developed an accurate digital overview of those movements using motion capture and 3D animal reconstruction. Finally, we structured a database for archiving all behavioral data and demonstrated how those archives can be used for advancing behavioral research, providing ecological insights into this animal group. Our approach can enhance research on reptiles' behavior by contributing to the analysis of complex or isolated behaviors, poorly studied, such as signals and social interactions, providing valuable insights and assisting behavioral analysis.

Glucose transporters (GLUTs) play vital roles in cellular metabolism. Understanding their evolutionary dynamics in birds is essential for elucidating avian physiology and adaptation. However, the choice of gene detection method in gene family analysis may affect the conclusion. Here, we present a comprehensive investigation of methodologies and GLUT gene loss events in avian lineages, focusing on the loss of GLUT4 and GLUT8. To illustrate the effects of these methods, we first employed BUSCO-based homolog identification, calculated pairwise evolutionary distances between different species, and performed separate blastn and blastp searches to identify homologs in two groups of animals. Our analyses revealed a significant decline in blastn accuracy with increasing evolutionary distance, represented by relative divergence times. Through a more robust blastp-based gene detection pipeline, we provide evidence for the loss of GLUT genes in birds based on 58 vertebrate genomes, including 47 bird species. Our results support the reported early loss of GLUT4 in Aves. We also newly emphasize the absence of GLUT8 in passerines, potentially due to adaptation to high-sugar diets in their ancestors. These findings enhance our knowledge of avian metabolism and the evolution of GLUT genes.

The monito del monte co-occurred with birds and lizards in over 67% of the cavities. Co-occurrence probabilities increased at higher elevations for three lizard species. Co-occurrence probabilities decreased at higher elevations for two bird species. Bird and lizard activity overlapped less than 18% with that of monito del monte. A bird species declined its overlap in high-elevation forests.

In the avian midbrain network, bottom-up spatial attention is directed by saliency-based stimulus selection. However, it remains unclear whether the isthmi pars magnocellularis (Imc), the first site in the midbrain network representing stimulus selection, can represent stimulus salience and what is the mechanism by which the midbrain network computes salience. Here, two separate translational motion stimuli were adopted as principal stimulation protocols, and in vivo electrophysiological experiments were performed in pigeons' Imc. By combining bio-plausible model validation, we found two types of inhibitory surrounds of the Imc neuron receptive field, namely homologous inhibitory surrounds (HIS) and non-homologous inhibitory surrounds (non-HIS), and we expounded the mechanisms of their emergence. HIS is local and dependent on stimulus feature similarity for computing stimulus saliency, whereas non-HIS is global and independent of stimulus feature similarity for computing stimulus selection. Furthermore, the superimposition of HIS and non-HIS modulates the neural responses in Imc. The two identified inhibitory surrounds of Imc in this study more precisely explicate the entire process of realizing bottom-up stimulus selection based on saliency in the midbrain network and indicate that Imc is a nucleus capable of representing both stimulus saliency and stimulus selection.

Variation patterns in gut microbial diversity among host species and populations offer valuable insights into the mechanisms underlying environment-host-microbiome interactions. However, the extent to which host phylogeny and geography drive these variation patterns in animal gut microbiota remains an open question. Amphibians and reptiles are important models to address this issue. Using 194 gut microbial samples of three amphibian and four reptile species inhabiting the Tarim Desert, we demonstrated phylosymbiosis in these animals, which was associated with heterogeneous selection and dispersal limitation. In interpopulation comparisons, Bufotes pewzowi and Teratoscincus przewalskii exhibited geography-dependent variations in their gut microbiota, particularly in relation to longitude and annual precipitation. These geographical patterns were linked to the heterogeneous selection of microbiota. Interestingly, the microbiota of B. pewzowi and T. przewalskii showed parallel variations with longitude, suggesting common selective pressures on amphibian and reptile microbiota. Finally, we found host genetic background did not account for the geographical pattern in their gut microbiota, even though it was also associated with geographical factors. This suggested environment-microbe interaction as a potential and independent ecological pathway mediating the associations between the environment and animals. Overall, these findings extend our understanding of variation patterns in gut microbiota and shed light on the underlying mechanisms.

Mammals can use a variety of physiological mechanisms to adapt to changes in their environment. Thyroid hormones (THs) are key modulators of growth and mediators of environmental conditions by regulating developmental processes and metabolism in animals. In recent years, advancements in non-invasive sampling have allowed monitoring of the fluctuations of THs and their metabolites in wild mammals. Triiodothyronine (T3) represents the major metabolite of THs excreted in feces so that it can be monitored in fecal samples. In this study, fecal samples collected during the hunting season from legally culled European roe deer (Capreolus capreolus; n = 160) were assayed to investigate the potential fluctuations of fecal TH metabolites (FTMs) in response to environmental (e.g., the temperature, local densities) and individual (e.g., sex, age, body, and nutritional conditions) variables. For this aim, we validated a TH enzyme immunoassay in the feces of roe deer. Our results show that FTMs can be successfully measured with satisfactory accuracy and precision. Extraction recovery (70%-120%), intra- and inter-day repeatability (<15%), linearity dilutions (80%-120%), and parallelism (<20%) were consistent with international guidelines. Environmental temperature (p < 0.001) showed a strong inverse correlation with FTM levels. THs can thus represent a reliable indicator in studying animals' adaptative responses to environmental temperature changes, providing perspectives for the study of the impact of climate change on ungulates and mammals. Further analyses, comparing samples collected all year round, are needed to investigate the correlations of TH values versus the other investigated variables.

Greater thermal tolerance of invasive species benefits their survival and spread under extreme climate events, especially under global warming. Revealing the mechanisms underlying the interspecific differences in thermal tolerance between invasive and native species can help understand the invasion process and predict potential invaders. Here, we link the changes in global transcriptomics and antioxidant defense at multiple temperatures with the differences in thermal limits in the juveniles of a successful globally invasive turtle, Trachemys scripta elegans, and a native turtle in China, Mauremys reevesii. The two species show different thermal tolerances and have co-existed in habitats with the risk of overheating. The majority of the transcriptional response to thermal stress is conserved in the two turtle species, including protein folding or DNA damage responses activated under relatively moderate thermal stress and regulation of the cell cycle and apoptosis during severe thermal stress. Greater thermal tolerance of T. scripta elegans can be associated with a more stable global transcriptome during thermal stress, except for necessary stress responses, and a broader thermal range of continuous up-regulation of the core mechanisms promoting survival under thermal stress, mainly protein folding and negative regulation of apoptosis. Under extreme hot conditions, the opposite change trends of genes involved in survival mechanisms during thermal stress between invasive and native turtles can be due to differences in energy turnover. The present study provides insights into the mechanisms of physiological differences between invasive and native species given global transcriptional changes and helps understand successful invasion and predict potential invasive species.