Safe overwintering is a challenging issue in rearing management that is inevitably faced by beekeepers in high-latitude regions. Under the combined influence of multiple factors, the overwintering loss rate of Western honey bees has risen continuously, and investigating the molecular mechanisms related to safe overwintering has become key. The Hunchun bee, an Apis mellifera ecotype in Jilin Province, China, exhibits strong overwintering ability during an overwintering period of more than five months. To investigate the molecular mechanisms of its cold resistance, we conducted a comparative transcriptomic analysis between the summer breeding period (July) and different overwintering intervals (November, December, January, and February), and then systematically identified key genes and signaling pathways related to cold resistance. The results showed that the highest number of differentially expressed genes (DEGs) was found between December and July. Compared with July, the upregulated genes in Hunchun bee in December were significantly enriched in several pathways, such as ion transport and neuroactive ligand–receptor interactions, and the downregulated genes were significantly enriched in pathways related to fatty acid metabolism, glutathione metabolism, and the peroxisome. Notably, a total of 378 shared DEGs were obtained from the four comparison groups, and several candidate cold-resistant gene families, such as AFPs, HSPs, C₂H₂-ZFPs, STKs, and LRRCs, were identified among the shared DEGs of the winter season. Additionally, 749 shared DEGs related to protein modification and metabolic process regulation were identified between the four successive overwintering intervals. Four shared genes, including sensory neuron membrane protein 1 (SNMP1), were revealed by pairwise comparison of the four intervals. The above results collectively indicate that the Hunchun bee attenuates winter-induced stress responses during the overwintering process by maintaining osmotic pressure balance, reducing fatty acid metabolism, increasing antioxidant capacity, and synthesizing cold-resistant macromolecular proteins. It was also found that chemical signal perception may serve a role in maintaining the stability of the overwintering bee colony. The key genes and pathways related to cold resistance identified in this study not only provide a basis for explaining the overwintering molecular mechanism for Apis mellifera of Hunchun bee but also offer key data to improve overwintering management strategies for Western honey bees.

The conservation and breeding of the western honey bee (Apis mellifera) is central dependent on accurate subspecies assignment, but the most commonly used methods are labor-intensive classical morphometrics and costly molecular assays. We developed an XGBoost-based classification framework using a compact set of routinely measurable characters. A curated dataset of labeled workers was measured under harmonized protocols; features were screened according to embedded importance, and model performance was assessed using five-fold cross-validation, outperforming standard machine learning baselines. The resulting model using only the top 10 characters—primarily forewing venation angles and abdominal plate metrics—achieved high performance (accuracy = 0.98; F1 = 0.99) and an area under the receiver operating characteristic curve (AUC) of 0.99 (95% CI = 0.995–0.999). SHAP analyses confirmed the discriminatory contributions of these features, while error inspection suggested that misclassifications were concentrated in morphologically overlapping lineages. The model’s performance supports its use as a rapid triage tool alongside genetic testing, providing a scalable and interpretable tool for researchers to create and deploy custom morphometric models, demonstrated here for A. mellifera but portable to other insect taxa.

Jujube flower disease (JFD) is a recurrent disorder affecting honeybees during the flowering period of Ziziphus jujuba, but its molecular basis remains unclear. To characterize JFD-associated molecular changes, we integrated widely targeted metabolomics and RNA sequencing (RNA-seq) in exposed asymptomatic jujube flower foragers (HC) and in bees showing characteristic JFD symptoms. Filtered metabolomic profiles showed clear separation between HC and JFD samples and revealed two major metabolite-level alterations. Tryptophan metabolism was the strongest enriched pathway among differentially abundant metabolites (Rich Factor = 14/16; FDR = $9.15\times {10}^{-7}$), whereas metabolites decreased in JFD were enriched mainly in galactose metabolism (Rich Factor = 7/16; FDR = $1.23\times {10}^{-4}$), amino sugar and nucleotide sugar metabolism (Rich Factor = 5/15; FDR = 0.00762), biosynthesis of nucleotide sugars (Rich Factor = 4/15; FDR = 0.0318), and starch and sucrose metabolism (Rich Factor = 3/8; FDR = 0.0318). RNA-seq detected 10,259 genes and identified 23 differentially expressed genes under the selected threshold, including 20 increased and 3 decreased genes in JFD bees. Although individual-gene differential expression was limited, preranked gene-set enrichment analysis identified moderate negative enrichment of the sugar supply/storage gene set (NES = −1.96; FDR = 0.024). The tryptophan/aromatic amino acid gene set was not enriched at the transcriptomic level, indicating that the tryptophan-related alteration was mainly observed at the metabolite level. Within these gene sets, HK showed the largest downward RNA-seq trend among the five displayed sugar-axis enzyme genes and a directionally concordant qRT-PCR trend; on this basis, HK was retained only as a candidate for future functional validation. Overall, these findings suggest that JFD is associated with altered tryptophan-related metabolism and reduced carbohydrate/nucleotide sugar-related metabolite abundance, with partial transcriptomic support for altered sugar supply and storage. This molecular profile provides candidate pathways and genes for future mechanistic investigation rather than established biomarkers, regulatory mechanisms, or evidence of disease causation.

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.

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 collection of honey and propolis is crucial for the nutrition and health of honey bee colonies. In this study, Apis mellifera with high productivity for both honey and propolis (MJ) was developed through long-term selective breeding using Apis mellifera caucasica and Apis mellifera carnica as breeding materials, resulting in substantial improvements in both honey yield and propolis production. To elucidate the genetic basis and molecular mechanisms underlying efficient foraging behavior for nectar and resins in honey bees, whole-genome resequencing was performed on MJ, the C-lineage, and the O-lineage of Apis mellifera. In addition, transcriptome sequencing was conducted using MJ and Apis mellifera ligustrica, which exhibited the highest honey and propolis production traits. MJ had a composite genetic background dominated by O-lineage ancestry. Compared with C-lineage honey bees, MJ exhibited 234 candidate genes under selection, mainly related to chitin and amino sugar metabolism. Transcriptome analysis identified 504 and 2676 differentially expressed genes between MJ and Italian honey bees in the nectar-forager and resin-forager comparisons, respectively, involving chemosensory gene families. Genes upregulated in MJ nectar and resin foragers were mainly associated with redox regulation and energy metabolism, respectively. Integrated analyses identified 7 candidate genes associated with nectar foraging and 41 candidate genes associated with resin foraging; these genes were involved in chemosensory responsiveness, flight-related structural traits, energy metabolism, and redox regulation in MJ. These findings provide genetic and transcriptomic resources for further studies on the division of labor in foraging and molecular breeding in honey bees.