摘要: Gut microbiota play important roles in the immunity, digestion, and energy metabolism of their reptile hosts. Mangshan pit viper (Protobothrops mangshanensis) is a critically endangered snake species that is a Class I national protected species in China. Little is known regarding the relationship between P. mangshanensis and their gut microbial communities. In this study, the gut microbiota of wild P. mangshanensis individuals, artificially hibernating captive individuals, and non-hibernating captive individuals were compared across nine samples. Comparative shotgun metagenomic analysis was used to investigate the taxonomic composition, diversity, and function of P. mangshanensis gut microbial communities and assess whether their gut microbiomes were affected by their living environments and captivity conditions. The dominant phyla within P. mangshanensis gut microbial communities were Proteobacteria (65.55%), Bacteroidetes (15.97%), and Firmicutes (8.11%). Enriched functional pathways within the gut microbiota included metabolism (54.9%), environmental information processing (9.67%), and genetic information processing (9.37%). Wild snake gut communities exhibited higher microbial diversity than the other two groups. The gut microbiomes of wild and hibernating captive snakes may be more reflective of healthy intestinal homeostasis than that in non-hibernating snakes. Specifically, non-hibernating snakes exhibited increased levels of potentially pathogenic populations and functional specialization within gut microbial communities. Thus, different living environments and captivity methods may correspond to major shifts in microbiota composition, diversity, and function within P. mangshanensis. This study provides important insights to help guide the conservation of P. mangshanensis, while also carrying broad implications for our understanding of the effects of living environments and non-hibernating captivity conditions on the gut microbiota of snakes.

摘要: Understanding the process of adaptation is a key mission in modern evolutionary biology. Animals living at high elevations face challenges in energy metabolism due to several environmental constraints (e.g., oxygen supply, food availability, and movement time). Animal behavioral processes are intimately related to energy metabolism, and therefore, behavioral modifications are expected to be an important mechanism for high-elevation adaptation. We tested this behavioral adaptation hypothesis using variations of motion visual displays in toad-headed aga mid lizards of the genus Phrynocephalus. We predicted that complexity of visual motion displays would decrease with the increase of elevation, because motion visual displays are energetically costly. Displays of 12 Phrynocephalus species were collected with elevations ranging from sea level to 4600 m. We quantified display complexity using the number of display components, display duration, pathways of display components, as well as display speed for each species. Association between display complexity and elevation was analyzed using the phylogenetic generalized least squares (PGLS) model. We found that both the number of display components and the average value of tail coil speed were negatively correlated with elevation, suggesting that toad-headed lizards living at high-elevation areas reduced their display complexity to cope with the environmental constraints. Our research provides direct evidence for high-elevation adaptation from a behavioral aspect and illustrates the potential impacts of environment heterogeneity on motion visual display diversification.

摘要: Animals living in heterogeneous natural environments adopt different camouflage strategies against different backgrounds, and behavioral adaptation is crucial for their survival. However, studies of camouflage strategies have not always quantified the effect of multiple strategies used together. In the present study, we used a human visual model to quantify similarities in color and shape between the carapace patterns of two Cuora species and their preferred habitats. Our results showed that the color of the middle stripe on the carapace of Cuora galbinifrons (Indochinese box turtle) was significantly similar to the color of their preferred substrates. Meanwhile, the middle stripe on the carapace of C. mouhotii (keeled box turtle) contrasted more with their preferred substrates, and the side stripe matched most closely with the environment. Furthermore, the carapace side stripe of C. galbinifrons and the carapace middle stripe of C. mouhotii highly contrasted with their preferred substrates. We quantified the similarity in shape between the highcontrast stripes of both Cuora species and leaves from their habitats. The carapace middle stripe of C. mouhotii was most similar in shape to leaves from the broadleaves substrate, and the carapace side stripe of C. galbinifrons was the most similar in shape to leaves from the bamboo-leaves substrate. We determined that these species adopt partial masquerading when their entire carapace is exposed and partially match their background when they semi-cover themselves in leaf litter. To the best of our knowledge, this is the first study to demonstrate that partial masquerading and background matching improve the camouflage effect of Asian box turtles in their preferred habitats. This is a novel study focusing on the influence of the shape and color of individual carapace segments on reducing detectability and recognition.

摘要: The Chinese sucker, Myxocyprinus asiaticus (M. asiaticus, Catostomidae, Cypriniformes), is the only living species of Catostomidae in Asia. There are more than 75 species of this family in North America. The fossil record of this group dates back to the early Eocene. As the Chinese sucker is located at the base of the Cyprinoidei phylogeny, this species is also important in clarifying the evolutionary relationships within Cyprinoidei. Here, we assembled a high-quality genome of the Chinese sucker, contig N50 (40.26 Mb), which is nearly ten times longer than the previous version (4.19 Mb). Phylogenetic analysis identified that Chinese sucker together with Cyprinidae groups are paraphyletic with respect to Cobitoidea. The specific whole genome duplication event of the Chinese sucker was estimated to have occurred similar to 25.9 million years ago. Analysis of population historical changes indicated a trend of reduction for the Chinese sucker and T. tibetana. Since Dlx genes play a key role in Cypriniformes pharyngeal teeth development, we conducted a genome-wide identification of Dlx genes, and found that these genes were doubled in whole genome duplication events, followed by the loss of specific copies. Transcriptome results showed that the expression levels of these paralogous genes were similar. This genomic resource provides useful information for the protection of Chinese sucker and functional study of Dlx genes.