Wenjun Peng

Diversity of Nosema associated with bumblebees (Bombus spp.) from China

Bumblebees (Bombus spp.) are important pollinators of many economically important crops and microsporidia are among the most important infections of these hosts. Using molecular markers, we screened a large sample (n=1,009 bees) of workers of 27 different Bombus spp. from China (Sichuan, Qinghai, Inner Mongolia, and Gansu provinces). The results showed that 62 individuals representing 12 Bombus spp. were infected by microsporidia with an overall prevalence of 6.1%. Based on the haplotypes (ssrRNA sequences), we confirmed the presence of Nosema bombi, Nosema ceranae and (likely) Nosema thomsoni. In addition, four new putatively novel taxa were identified by phylogenetic reconstruction: Nosema A, Nosema B-complex, Nosema C-complex and Nosema D-complex. In many cases, hosts were infected by more than one Nosema taxon. Possible caveats of sequence analyses are discussed.

Next-generation small RNA sequencing for microRNAs profiling in Apis mellifera: comparison between nurses and foragers.

MicroRNAs (miRNAs) are endogenous small non‐coding RNAs regulating gene expression in animals and plants. To find some differentially expressed miRNAs that may be associated with age‐dependent behavioural changes in honey bees (Apis mellifera), we applied next‐generation high‐throughput sequencing technology to detect small RNAs in nurses and foragers. Our results showed that both nurses and foragers had a complicated small RNA population, and the length of small RNAs varied, 22 nucleotides being the predominant length. Combining deep sequencing and bioinformatic analysis, we discovered that nine known miRNAs were significantly different between nurses and foragers (P < 0.01; absolute value of fold‐change ≥1). Some of their target genes were related to neural function. Moreover, 67 novel miRNAs were identified in nurses and foragers. Ame‐miR‐31a and ame‐miR‐13b were further validated using quantitative reverse‐transcription PCR assays. The present study provides new information on the miRNA abundance of honey bees, and enhances our understanding of miRNA function in the regulation of honey bee development.

The Prevalence of Parasites and Pathogens in Asian Honeybees Apis cerana in China

Pathogens and parasites represent significant threats to the health and well-being of honeybee species that are key pollinators of agricultural crops and flowers worldwide. We conducted a nationwide survey to determine the occurrence and prevalence of pathogens and parasites in Asian honeybees, Apis cerana, in China. Our study provides evidence of infections of A. cerana by pathogenic Deformed wing virus (DWV), Black queen cell virus (BQCV), Nosema ceranae, and C. bombi species that have been linked to population declines of European honeybees, A. mellifera, and bumble bees. However, the prevalence of DWV, a virus that causes widespread infection in A. mellifera, was low, arguably a result of the greater ability of A. cerana to resist the ectoprasitic mite Varroa destructor, an efficient vector of DWV. Analyses of microbial communities from the A. cerana digestive tract showed that Nosema infection could have detrimental effects on the gut microbiota. Workers infected by N. ceranae tended to have lower bacterial quantities, with these differences being significant for the Bifidobacterium and Pasteurellaceae bacteria groups. The results of this nationwide screen show that parasites and pathogens that have caused serious problems in European honeybees can be found in native honeybee species kept in Asia. Environmental changes due to new agricultural practices and globalization may facilitate the spread of pathogens into new geographic areas. The foraging behavior of pollinators that are in close geographic proximity likely have played an important role in spreading of parasites and pathogens over to new hosts. Phylogenetic analyses provide insights into the movement and population structure of these parasites, suggesting a bidirectional flow of parasites among pollinators. The presence of these parasites and pathogens may have considerable implications for an observed population decline of Asian honeybees.

Cross-Species Infection of Deformed Wing Virus Poses a New Threat to Pollinator Conservation

ABSTRACT The Deformed wing virus (family Iflaviridae, genus Iflavirus, DWV), one of the most prevalent and common viruses in honey bees, Apis mellifera L., is present in both laboratory-reared and wild populations of bumble bees, Bombus huntii Greene. Our studies showed that DWV infection spreads throughout the entire body of B. huntii and that the concentration of DWV is higher in workers than in males both collected in the field and reared in the laboratory, implying a possible association between the virus infection and foraging activities. Further results showed that gut tissue of B. huntii can support the replication of DWV, suggesting that B. huntii is a biological host for DWV, as are honey bees. Bumble bees and honey bees sometimes share nectar and pollen resources in the same field. The geographical proximity of two host species probably plays an important role in host range breadth of the virus.

Host range expansion of honey bee Black Queen Cell Virus in the bumble bee, Bombus huntii

Here we provide the first evidence that Black Queen Cell Virus (BQCV), one of the most prevalent honey bee viruses, can cause an infection in bumble bees, Bombus huntii, and that the BQCV infection could spread to different tissues of bumble bees. The detection of negative strand RNA of BQCV, an indicator of active virus replication, in the gut of B. huntii suggests that virus particles replicate within the gut and then cross the gut lining to other tissues through hemolymph circulation. The observation of active replication of the BQCV in the gut, together with the fact that BQCV was more widespread in the body of field-collected bees than that of lab-reared bees, implies a possible association between the foraging activities of bumble bees and virus transmission. The fact that bumble bees and honey bees are able to share nectar and pollen resources in the same field suggests that geographical proximity of two host species could play a role in host range breadth of BQCV.

Sensitivities of three bumblebee species to four pesticides applied commonly in greenhouses in China

Abstract  This study was conducted to evaluate the effects of four pesticides (Mosplian, Kingbo, Score and Lvrtong) applied commonly in greenhouses in China, on three bumblebee species (Bombus hypocrita, Bombus ignitus and Bombus patagiatus). The study used a contact experiment and oral toxicity LD50 values. The results showed that the mortality for B. hypocrita after contacting the four pesticides was significantly lower than B. patagiatus and B. ignitus, but there was no significant difference between B. patagiatus and B. ignitus. The oral toxicity median lethal dose (LD50) value of Mosplian to B. hypocrita (0.0028 μg active ingredient/bee) was significantly higher than that to B. ignitus (0.0023 μg active ingredient/bee) and B. patagiatus (0.0021 μg active ingredient/bee). Of the bee species, it can be concluded that B. hypocrita was the least susceptible to the four pesticides. The mortality rates of each bumblebee species after contact with Mosplian were significantly higher than for the other three pesticides and the control group. For Kingbo, the rates were significantly higher than the control group, but Score and Lvrtong exposed groups showed no significant increase in mortality relative to the control group. It can therefore be concluded that the pesticides differ in their negative influences on bumblebees, and that Mosplian is the most harmful.

Comparison of the colony development of two native bumblebee species Bombus ignitus and Bombus lucorum as candidates for commercial pollination in China

Summary Studies of the colony development of the Chinese bumble bees Bombus ignitus and Bombus lucorum found that there were four oviposition phases. The average number of workers produced per colony of B. ignitus and B. lucorum was 107 and 104 respectively, there being no significant difference between them (p>0.05). Colonies produced daughter queens in Phase 4 and the average number of new queens produced per colony of B. ignitus was smaller than that of B. lucorum (p<0.05). The proportion of B. ignitus and B. lucorum queens which established nests was on average 89% and 84% respectively (p>0.05). The average time to the emergence of the first workers in B. lucorum was longer than in B. ignitus, and this was significantly different (p<0.05), but the percentage of successful colony production of B. lucorum was lower than that of B. ignitus, and the number of workers which had emerged at above 30 days after first the oviposition in B. lucorum was more than in B. ignitus.

Reply to “Conclusive Evidence of Replication of a Plant Virus in Honeybees Is Lacking”

We appreciate Miller et al. (1) for taking the time to offer comments related to our paper “Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera” (2). We provide the following responses for clarification. The study on the pathogenesis of virus infections in honeybees has been hampered by the lack of a robust cell culture system for viral replication. The detection and quantification of negative-strand RNA intermediates offer an excellent alternative for the demonstration of virus replication and pathogenesis in infected hosts. However, there have been concerns regarding strand specificity of the method due to false priming events during reverse transcription, which, as pointed out by Miller et …

Altered Serum Metabolite Profiling and Relevant Pathway Analysis in Rats Stimulated by Honeybee Venom: New Insight into Allergy to Honeybee Venom

To improve our understanding of the disturbed metabolic pathways and cellular responses triggered by honeybee venom stimulation, we compared the changes in serum metabolites in rats, either stimulated or not by honeybee venom, by performing 1H nuclear magnetic resonance (NMR) spectrometry-based metabonomics to identify potential biomarkers. In this study, 65 metabolites were structurally confirmed and quantified and the following results were obtained. First, by pattern recognition analysis, 14 metabolites were selected as potential biomarkers 3 h after venom stimulation. Second, metabolic pathway analysis showed that methane metabolism, glyoxylate and dicarboxylate metabolism, tricarboxylic acid cycle, glycine, serine, and threonine metabolism, arginine and proline metabolism were affected. Finally, the time-dependent metabolic modifications indicated that rats could recover without medical treatment 24 h after venom stimulation. In summary, this new insight into the changes in serum metabolites in rats after honeybee venom stimulation has enhanced our understanding of the response of an organism to honeybee venom.

A descriptive study of the prevalence of parasites and pathogens in Chinese black honeybees

The Chinese black honey bee is a distinct honey bee subspecies distributed in the Xinjiang, Heilongjiang and Jilin Provinces of China. We conducted a study to investigate the genetic origin and the parasite/pathogen profile on Chinese black honeybees. The phylogenetic analysis indicated that Chinese black honeybees were two distinct groups: one group of bees formed a distinct clade that was most similar to Apis mellifera mellifera and the other group was a hybrid of the subspecies, Apis mellifera carnica, Apis mellifera anatolica and Apis mellifera caucasica. This suggests that the beekeeping practices might have promoted gene flow between different subspecies. Screening for pathogens and parasites showed that Varroa destructor and viruses were detected at low prevalence in Chinese black honeybees, compared with Italian bees. Further, a population of pure breeding black honeybees, A. m. mellifera, displayed a high degree of resistance to Varroa. No Varroa mites or Deformed wing virus could be detected in any examined bee colonies. This finding suggests that a population of pure breeding Chinese black honeybees possess some natural resistance to Varroa and indicated the need or importance for the conservation of the black honeybees in China.