Different effects of pesticides on transcripts of the endocrine regulation and energy metabolism in honeybee foragers from different colonies

Metabolism gene expression in worker honey bees after exposure to 50Hz electric field - semi-field analysis

The investigation of the effects of artificial 50 Hz electric field (E-field) frequency on Apis mellifera is a relatively new field of research. Since the current literature focuses mainly on short-term effects, it is unknown whether E-fields have permanent effects on bees or whether their effects can be neutralized. In this study we assessed gene expression immediately after exposure to the E-field, as well as 7 days after exposure. The aim of this work was to identify potentially dysregulated gene transcripts in honey bees that correlate with exposure time and duration to E-fields.Newly emerged bees were marked daily with a permanent marker (one color for each group). Then bees were exposed to the 50 Hz E-field with an intensity of 5.0 kV/m or 10.0 kV/m for 1-3 h. After exposure, half of the bees were analyzed for gene expression changes. The other half were transferred to a colony kept in a mini-hive. After 7 days, marked bees were collected from the mini-hive for further analysis. Six regulated transcripts were selected of transcripts involved in oxidative phosphorylation (COX5a) and transcripts involved in endocrine functions (HBG-3, ILP-1), mitochondrial inner membrane transport (TIM10), and aging (mRPL18, mRPS30).Our study showed that in Apis mellifera the expression of selected genes is altered in different ways after exposure to 50 Hz electric fields -. Most of those expression changes in Cox5a, mRPL18, mRPS30, and HGB3, were measurable 7 days after a 1-3 h exposure. These results indicate that some E-field effects may be long-term effects on honey bees due to E-field exposure, and they can be observed 7 days after exposure.

Distinct fungal microbiomes of two Thai commercial stingless bee species, Lepidotrigona terminata and Tetragonula pagdeni suggest a possible niche separation in a shared habitat

Stingless bees, a social corbiculate bee member, play a crucial role in providing pollination services. Despite their importance, the structure of their microbiome, particularly the fungal communities, remains poorly understood. This study presents an initial characterization of the fungal community associated with two Thai commercial stingless bee species, Lepidotrigona terminata (Smith) and Tetragonula pagdeni (Schwarz) from Chiang Mai, Thailand. Utilizing ITS amplicon sequencing, we identified distinct fungal microbiomes in these two species. Notably, fungi from the phyla Ascomycota, Basidiomycota, Mucoromycota, Mortierellomycota, and Rozellomycota were present. The most dominant genera, which varied significantly between species, included Candida and Starmerella. Additionally, several key enzymes associated with energy metabolism, structural strength, and host defense reactions, such as adenosine triphosphatase, alcohol dehydrogenase, β-glucosidase, chitinase, and peptidylprolyl isomerase, were predicted. Our findings not only augment the limited knowledge of the fungal microbiome in Thai commercial stingless bees but also provide insights for their sustainable management through understanding their microbiome.

Variation in the physiological response of adult worker bees of different ages (Apis mellifera L.) to pyraclostrobin stress

The social division of labor within the honeybee colony is closely related to the age of the bees, and the age structure is essential to the development and survival of the colony. Differences in tolerance to pesticides and other external stresses among worker bees of different ages may be related to their social division of labor and corresponding physiological states. Pyraclostrobin was widely used to control the fungal diseases of nectar and pollen plants, though it was not friend to honey bees and other pollinators. This work aimed to determine the effects of field recommended concentrations of pyraclostrobin on the activities of protective and detoxifying enzymes, on the expression of genes involved in nutrient metabolism, and immune response in worker bees of different ages determined to investigate the physiological and biochemical differences in sensitivity to pyraclostrobin among different age of worker bees. The result demonstrates that the tolerance of adult worker bees to pyraclostrobin was negatively correlated with their age, and the significantly reduced survival rate of forager bees (21 day-old) with continued fungicide exposure. The activities of protective enzymes (CAT and SOD) and detoxifying enzymes (CarE, GSTs and CYP450) in different ages of adult worker bees were significantly altered, indicating the physiological response and the regulatory capacity of worker bees of different ages to fungicide stress was variation. Compared with 1 and 8 day-old worker bees, the expression of nutrient-related genes (ilp1 and ilp2) and immunity-related genes (apidaecin and defensin1) in forager bees (21 day-old) was gradually downregulated with increasing pyraclostrobin concentrations. Moreover, the expression of vitellogenin and hymenoptaecin in forager bees (21 day-old) was also decreased in high concentration treatment groups (250 and 313 mg/L). The present study confirmed the findings of the chronic toxicity of pyraclostrobin on the physiology and biochemistry of worker bees of different ages, especially to forager bees (21 day-old). These results would provide important physiological and biochemical insight for better understanding the potential risks of pyraclostrobin on honeybees and other non-target pollinators.