The blue whistling thrush (Myophonus caeruleus) is a bird belonging to the order Passeriformes and family Muscicapidae. M. caeruleus is widely distributed in China, Pakistan, India, and Myanmar and is a resident bird in the southern part of the Yangtze River in China and summer migratory bird in the northern part of the Yangtze River. At present, there are some controversies about the classification of M. caeruleus. We use complete mitochondrial genomes to provide insights into the phylogenetic position of M. caeruleus and its relationships among Muscicapidae. The mitochondrial genome (GenBank: MN564936) is 16,815 bp long and contains 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a non-coding control region (D-loop). The thirteen PCGs started with GTG and ATG and ended with five types of stop codons. The nucleotide composition of T was 23.71%, that of C was 31.45%, that of A was 30.06%, and that of G was 14.78%. The secondary structures of 22 tRNAs were predicted, all of which could form typical cloverleaf structures. There were 24 mismatches, mainly G–U mismatches. Through phylogenetic tree reconstruction, it was found that Saxicola, Monticola, Oenanthe, and Phoenicurus were clustered into one clade, together with the sister group of Myophonus.

Nuthatches (genus Sitta; family Sittidae) are a passerine genus with a predominantly Nearctic and Eurasian distribution. To understand the phylogenetic position of Sitta and phylogenetic relations within this genus, we sequenced the complete mitochondrial genomes of three Sitta species (S. himalayensis, S. nagaensis, and S. yunnanensis), which were 16,822–16,830 bp in length and consisted of 37 genes and a control region. This study recovered the same gene arrangement found in the mitogenomes of Gallus gallus, which is considered the typical ancestral avian gene order. All tRNAs were predicted to form the typical cloverleaf secondary structures. Bayesian inference and maximum likelihood phylogenetic analyses of sequences of 18 species obtained a well-supported topology. The family Sittidae is the sister group of Troglodytidae, and the genus Sitta can be divided into three major clades. We demonstrated the phylogenetic relationships within the genus Sitta (S. carolinensis + ((S. villosa + S. yunnanensis) + (S. himalayensis + (S. europaea + S. nagaensis)))).

There is an urgent need to find a way to improve the genetic diversity of captive South China tiger (SCT, Panthera tigris amoyensis), the most critically endangered taxon of living tigers, facing inbreeding depression. The genomes showed that 13 hybrid SCTs from Meihuashan were divided into two groups; one group included three individuals who had a closer relationship with pureblood SCTs than another group. The three individuals shared more that 40% of their genome with pureblood SCTs and might be potential individuals for genetic rescuing in SCTs. A large-scale genetic survey based on 319 pureblood SCTs showed that the mean microsatellite inbreeding coefficient of pureblood SCTs decreased significantly from 0.1789 to 0.0600 (p = 0.000009) and the ratio of heterozygous loci increased significantly from 38.5% to 43.2% (p = 0.02) after one individual of the Chongqing line joined the Suzhou line and began to breed in the mid-1980s, which is a reason why the current SCTs keep a moderate level of microsatellite heterozygosity and nucleotide diversity. However, it is important to establish a back-up population based on the three individuals through introducing one pureblood SCT into the back-up population every year. The back-up population should be an important reserve in case the pureblood SCTs are in danger in the future.

Background: The interaction and co-evolution between the gut microbiome and the host play important roles in the host’s physiology, nutrition, and health. Diet is considered an important driver of differences in the gut microbiota; however, research on the relationship between the gut microbiota and diet in Asian elephants remains limited. Methods: In this study, we explored the gut microbiota structure and its relationship with diet in different populations of Asian elephants through metagenomic sequencing, combined with previously published dietary data. Results: This study found that the dominant gut microbiota of Asian elephants includes the phyla Bacillota (29.85% in BP, 22.79% in RC, 21.89% in SM, 31.67% in ML, and 33.00% in NGH), Bacteroidota (25.25% in BP, 31.44% in RC, 16.44% in SM, 25.73% in ML, and 23.74% in NGH), and Spirochaetota (3.49% in BP, 6.18% in RC, 1.71% in SM, 2.69% in ML, and 3.52% in NGH), with significant differences in the gut microbiota among different populations. Correlation analysis between the gut microbiota and diet revealed that dietary diversity did not directly affect the alpha diversity of the gut microbiota. However, specific food types might play a key role in shaping the gut microbiota structure by regulating the abundance of certain microbiota. Conclusions: This study reveals significant differences in the gut microbiota structure among different populations of Asian elephants and explores the impact of diet on the structure. The results provide foundational data for a deeper understanding of the gut microbiota structure of Asian elephants and offer important references for the scientific conservation and precise management strategies of this species.

Sympatric closely related species may experience interspecific trophic competition due to ecological similarity; they may isolate in terms of diet or habitat use as a strategy to avoid competition. The body tissues of consumers contain stable isotope signatures information that can be applied to infer their dietary information. In this study, δ¹³C and δ¹⁵N stable isotopes were analyzed to determine the dietary information and trophic niches of sympatric coexisting Sitta yunnanensis and Sitta nagaensis. The results showed that the food sources of S. yunnanensis and S. nagaensis were from six orders, including Orthoptera, and the cumulative contribution rate was 99.97%, with the two species eating similar diets but at different rates. The larger δ¹³C of S. yunnanensis indicates that it had a wider range of habitats for feeding, while the difference in δ¹⁵N values was not significant (p > 0.05), indicating that both species feed on similar nutrient levels. As determined by Bayesian ellipses, the isotopic niches of S. yunnanensis and S. nagaensis were differentiated; the isotopic niche width of S. yunnanensis is 2.69‰², which was larger than that of S. nagaensis (0.73‰²), indicates that differentiation between the two species in diet or habitat use reduced competition. Trophic niche differentiation and differences in foraging proportions may be the principal resource allocation mechanisms behind S. yunnanensis and S. nagaensis coexistence.