This study was conducted to investigate the deposition of several mineral elements and the mRNA levels of mineral-related genes across different tissues of cherry valley ducks. The contents of magnesium (Mg), potassium (K), zinc (Zn), and selenium (Se) in ducks’ breast muscle, thigh muscle, liver, skin, and tibia at the age of 0, 21, 35, 49, and 63 days, respectively, were measured using an atomic fluorescence spectrophotometer, while the mRNA levels of mineral-related genes were detected by qRT-PCR. The results revealed that the dynamics of Mg and K were generally similar in each tissue, with a significant positive correlation (p < 0.05). In the breast muscle, thigh muscle, and liver, the contents of almost all mineral elements reached their peak values (p < 0.05) at the age of 49 to 63 days. Interestingly, the expression of most mineral-related genes was the highest at birth (p < 0.05). In addition, there was a significant negative correlation between the expression of ATP1A1 and the deposition of K (r = −0.957, p < 0.05), and a similar result was found for the expression of ATP8 and the deposition of Zn (r = −0.905, p < 0.05). Taken together, Mg and K could be used as joint indicators for the precise breeding of the high-quality strain of cherry valley ducks, while the age of 49 to 63 days could be used as the reference for the best marketing age. In addition, ATP1A1 and ATP8 could be used as the key genes to detect K and Zn, respectively. Hence, the findings of this study can be used to improve the production and breeding efficiency of high-quality meat ducks.

The mandibular gland in worker bees synthesizes and secretes the organic acids present in royal jelly, and its development directly affects yield and quality. Therefore, we aimed to analyze the differences in morphology and gene expression in the mandibular glands of Apis mellifera carnica worker bees of different ages (3, 6, 9, 12, and 16 d). We dissected their mandibular glands and performed morphological and transcriptomic analyses to investigate the development of the mandibular gland and the molecular regulatory mechanisms involved in royal jelly secretion. Microscopy revealed that mandibular gland development is likely completed in the early stages. There were no significant differences in the structural morphology or organelles involved in the secretion of royal jelly at different ages. Transcriptomics revealed a total of 1554 differentially expressed genes, which were mainly involved in fat metabolism, lipid transport, and energy metabolism. The extracellular matrix–receptor interaction pathway was significantly enriched and contributed to the royal jelly secretion process. These results elucidate the genetic basis of the role of the mandibular gland in royal jelly secretion in A. mellifera and provide a reference for the genetic improvement of bees with high royal jelly production in the future.

Tibia morphology is a significant factor in poultry germplasm and market traits. Copy number variation (CNV) has been identified as a structural source of genetic variation for complex traits. We profiled genome-wide CNVs in Dong Tao chickens and nine other local breeds and performed a breed-based case–control CNV-GWAS (Dong Tao vs. reference breeds). We sequenced 152 chickens, including 46 Dong Tao, and annotated genes and pathways. A total of 22,972 CNVs were detected, of which 2193 were retained after filtration across 33 chromosomes, with sizes ranging from 2 kilobases to 12.8 megabases. Principal component analysis indicated an overall weakness in the breed structure and a sex-related trend within Dong Tao. A deletion on chromosome 3 at 36,529,501 to 36,539,000 was observed in Dong Tao. The exploratory screen identified 44 CNV regions at nominal significance (p < 0.05), distinguishing Dong Tao from other breeds. Thirty-seven regions contained 99 genes, including CHRM3 within the chromosome 3 deletion and CRADD overlapping two CNVs. Enrichment analysis indicated thiamine metabolism and growth hormone receptor signalling as the primary pathways of interest, with TPK1, SOCS2, and FHIT identified as potential candidates. These results provide a CNV landscape for Dong Tao and prioritize variant regions and pathways potentially relevant to its robust tibia morphology; however, no direct CNV–tibia phenotype regression was performed.

Cold tolerance is a key physiological determinant of colony overwintering survival and productivity in honey bees, yet quantitative phenotyping at the individual level remains a major challenge. Here, we developed a novel, non-invasive, multi-cubicle thermal testing platform that integrates the classical chill-coma recovery time (CCRT) and critical thermal minimum (CTmin) frameworks and introduces knockdown time—the interval from spontaneous locomotion to complete immobility under controlled cold exposure—as a quantitative index of individual cold tolerance. We evaluated this system by assaying 323 workers from two western honey bee (Apis mellifera) populations used in Chinese apiculture: the cold-adapted Dongbei bee and the cold-susceptible Apis mellifera ligustica, across two ages (10-day-old nurses and 20-day-old foragers) and two temperatures (6 and 10 °C). Three-way ANOVA revealed significant effects of population, age, and temperature, as well as their interactions: Dongbei bee workers exhibited ~1.4- to 1.9-fold longer knockdown times than A. m. ligustica in all age × temperature combinations, and foragers generally outperformed nurses in both populations, reflecting age- and task-related physiological adaptation. This work establishes a standardized, high-throughput platform for individual-level cold tolerance phenotyping, offering a promising tool for cold-tolerant honey bee breeding and a quantitative foundation for future mechanistic studies of thermal adaptation.

The honeybee (Apis mellifera) gut microbiota serves as a model for host–microbe studies, as newly emerged workers provide a low-complexity, nearly germ-free system. Although multiple inoculation strategies are commonly applied under laboratory conditions, their comparative effects on microbial colonization remain incompletely understood. Here, we systematically compared four commonly used inoculation strategies, including pollen mixture feeding, oral feeding, dunk inoculation, and comb-exposed inoculation, under controlled laboratory conditions using an identical microbial source. We assessed gut microbiota establishment using spike-in 16S rRNA gene sequencing, enabling the quantification of both relative and absolute bacterial abundances, together with analyses of community composition, alpha diversity, and beta diversity. Our results showed that method-dependent differences were observed. Pollen mixture feeding and oral feeding produced highly comparable outcomes across the measured parameters, suggesting that dietary incorporation and direct oral delivery are similarly effective for establishing core gut communities (p > 0.05). Dunk inoculation also supported core bacterial colonization, although differences in beta diversity indicated some variation in community structure (p < 0.05). Comb-exposed inoculation showed the most pronounced differences, with significantly reduced bacterial abundance, lower alpha diversity, and decreased colonization of specific core taxa including Bifidobacterium and Snodgrassella alvi (p < 0.05). Importantly, despite these differences, none of the inoculation methods resulted in atypical communities dominated by noncore taxa, indicating that the core gut microbiota remained broadly conserved across treatments. Collectively, our findings indicate that although inoculation delivery methods differed fundamentally in inoculum volume, microbial concentration, and the mechanisms by which microbes were introduced into the bee gut, these distinct strategies can introduce measurable differences, while the established gut communities remain consistently dominated by core bacterial taxa. These results provide a basis for selecting appropriate inoculation strategies in experimental studies of honeybee microbiota.

Chinese honey bees (Apis cerana cerana Fabricius, 1793) are crucial native pollinators in China, with substantial ecological and economic value. Their morphological traits may vary along altitudinal gradients, particularly in hilly regions such as Wanyuan City, Sichuan Province, which provides typical suitable habitat for a locally thriving ecotype known as the Wanyuan honey bee. To elucidate its adaptive variation across environmental gradients, this study investigated the morphological and genetic diversity of this ecotype along an altitudinal transect in Wanyuan. A total of 656 worker individuals from 15 sampling sites (565–1611 m) were analyzed for 13 morphological traits and mitochondrial DNA (tRNAleu–COII fragment) sequences. Results revealed significant altitudinal clines in morphology: Honey bees from mid-altitude sites exhibited larger body size for several traits, while low-altitude bees possessed a significantly higher number of hindwing hamuli. Key taxonomic indices like the cubital index and proboscis length also varied significantly with altitude. Genetic analysis identified 25 haplotypes with high haplotype diversity and nucleotide diversity, indicating substantial genetic variation. Population differentiation was generally low, with one site (Yinbazhai, 900 m) showing relatively higher distinctiveness. The detected high gene flow suggests frequent genetic exchange among most populations. These findings demonstrate that the Wanyuan honey bee exhibits clear altitudinal adaptation in morphology while maintaining high genetic diversity and connectivity. This study provides a crucial scientific basis for the conservation and sustainable management of this genetic resource by highlighting the importance of its population-specific adaptations and genetic structure.