The reproductive division of labor, based on caste differentiation in social insects, is of great significance in evolution. Generally, a healthy bee colony consists of a queen and numerous workers and drones. Despite being genetically identical, the queen and workers exhibit striking differences in morphology, behavior, and lifespan. The fertilized eggs and larvae selectively develop into queen and worker bees depending on the local nutrition and environment. Bee worker larvae that are transplanted within 3 days of age to queen cells of a bee colony can develop into queens with mature ovaries. This phenomenon is important to understand the regulatory mechanisms of caste differentiation. In this study, we transplanted worker larvae (Apis mellifera) at the age of 1 (L1), 2 (L2), and 3 days (L3) into queen cells until the age of 4 days. Subsequently, genetic changes in these larvae were evaluated. The results revealed that the number of differentially expressed genes (DEGs) in L1 vs. L3 was more than that in L1 vs. L2. Furthermore, many of the genes that were downregulated are mostly involved in metabolism, body development, reproductive ability, and longevity, indicating that these functions decreased with the age of transplantation of the larvae. Moreover, these functions may be critical for worker larvae to undergo the developmental path to become queens. We also found that the DEGs of L1 vs. L2 and L1 vs. L3 were enriched in the MAPK, FoxO, mTOR, Wnt, TGF-beta Hedgehog Toll and Imd, and Hippo signaling pathways. Gene ontology analysis indicated that some genes are simultaneously involved in different biological pathways; through these genes, the pathways formed a mutual regulatory network. Casein kinase 1 (CK 1) was predicted to participate in the FoxO, Wnt, Hedgehog, and Hippo signaling pathways. The results suggest that these pathways cross talked through the network to modify the development of larvae and that CK 1 is an important liaison. The results provide valuable information regarding the regulatory mechanism of environmental factors affecting queen development, thus, amplifying the understanding of caste differentiation in bees.

The gut microbiota of social bees is vital for host health, yet pesticide exposure can disrupt these communities. Because most active ingredients are poorly soluble, toxicological tests often use cosolvents, but their effects remain unclear. We assessed four common cosolvents (DMSO, DMF, acetone, and Tween 80) at laboratory-relevant concentrations on honeybee survival, pollen consumption, body weight, and gut microbiota. In parallel, in vitro assays tested their impact on five dominant gut symbionts. The results showed no significant changes in survival, feeding, body weight, bacterial load, community composition, or core taxa abundance. Similarly, cosolvents did not inhibit bacterial growth in vitro. These findings demonstrate that commonly used cosolvents exert no detectable influence on honeybee physiology or gut microbiota. Although negative, this evidence is critical: it rules out cosolvents as hidden confounders, improving confidence in pesticide toxicology studies and providing essential reference data for pollinator risk assessment.

There has been increased awareness of the negative effects of antibiotic use in poultry production, necessitating research on sustainable alternatives. Honeycomb polysaccharides (HPs) have attracted considerable attention due to their bioactivity. Therefore, we investigated the effects of HPs on growth and slaughter performance, antioxidant capacity, and immune function in Cyan-Shank Partridge chickens. Male Cyan-Shank Partridge chicks (n = 300; 1-day-old) were randomly assigned to five groups: negative control group (NC, fed a basal diet), three experimental groups (fed basal diet supplemented with 300 (HPs300), 600 (HPs600), or 1,200 mg/kg (HPs1200) of HPs), and chlortetracycline hydrochloride group (positive control group, PC). Compared to NC group, there was a significant increase (p < 0.05) in body weight at 20 days of age, average daily weight gain from day 1 to 20, and average daily feed intake from day 41 to 60 in the group HPs1200. Additionally, leg muscle ratio was significantly higher (p < 0.05) in group HPs1200 than in NC group. Compared with those in NC group, there was a significant decrease (p < 0.05) in serum malondialdehyde and a significant increase (p < 0.05) in serum superoxide dismutase activity in group HPs1200. Moreover, serum immunoglobulin A (IgA), IgM, and IgG levels were significantly higher (p < 0.05) in group HPs1200 than in group NC. Conclusively, HPs addition to feed at 1,200 mg/kg enhances growth performance, slaughter performance, serum antioxidant capacity, and immune function in Cyan-Shank Partridge chickens.

Prebiotics are widely used to modulate gut microbial communities, but their effects on the honey bee gut microbiota remain poorly understood. Xylo-oligosaccharides (XOS) are recognized as potential prebiotic substrates in humans and livestock, whereas their effects in honey bees have rarely been investigated in vivo. In this study, we evaluated the effects of dietary XOS supplementation on the gut microbiota of Apis mellifera. Total bacterial load and the absolute and relative abundances of five core bacterial groups (Lactobacillus Firm-5, Bombilactobacillus, Bifidobacterium, Gilliamella, and Snodgrassella alvi) were quantified using spike-in-based absolute 16S rRNA gene sequencing. Microbial diversity and community structure were further assessed using alpha-diversity indices and beta-diversity analyses. XOS supplementation did not significantly affect total bacterial abundance or the abundance of the five core bacterial groups (p > 0.05). No significant differences were detected in alpha diversity (p > 0.05), and the control and XOS groups exhibited largely overlapping community structures based on unweighted and weighted UniFrac analyses. However, PICRUSt2 analysis identified differences in several predicted microbial functional pathways between the two groups (p < 0.05). These results indicate that dietary XOS supplementation had limited detectable effects on the abundance, diversity, and structure of the established honey bee gut microbiota under the tested conditions, although changes in its predicted functional potential were observed. Our findings suggest that the efficacy of prebiotics in honey bees may depend on host-specific microbial ecology, and that prebiotic responses observed in mammalian systems may not be directly applicable to honey bees. These results highlight the importance of validating commercial prebiotic products using bee-specific in vivo evidence before their widespread application.