Wei-Yu Yan

Nutrition affects longevity and gene expression in honey bee (Apis mellifera) workers

Nutrition is a major factor affecting animal health, resistance to disease, and survival. In honey bees (Apis mellifera), nectar or honey (carbohydrates) is the energy source, while pollen, which is the sole dietary source of protein, is essential for both larval and adult development. Royal jelly (RJ), a secretion from workers with high protein content, plays a critical role in which queens are fed throughout their lives, is responsible for switching the worker phenotype into the queen one. The role of RJ in extending the lifespan of caged workers is not clear. In this study, we determined longevity of caged workers fed with different diets (carbohydrate only, pollen, and pollen+ RJ) and also expression of six genes in these bees. We found that workers fed with pollen and royal jelly together (P+ RJ+) showed the best survival, followed by workers fed with pollen only (P + RJ−), and workers fed with neither pollen nor RJ (P− RJ−) had the shortest life. Pollen only (P + RJ−) and royal jelly together (P+ RJ+) significantly affected four of the six genes studied. While pollen and royal jelly together (P+ RJ+) only affected the vitellogenin gene compared to pollen only (P+ RJ−). These results demonstrate that pollen and RJ extended worker longevity, suggesting that they may improve the nutritional conditions of bees or contain health and longevity-promoting factors. Further analysis of the lifespan-extending genes may broaden our understanding of gene network involved in the regulation of longevity.

Differential protein expression analysis following olfactory learning in Apis cerana

Studies of olfactory learning in honeybees have helped to elucidate the neurobiological basis of learning and memory. In this study, protein expression changes following olfactory learning in Apis cerana were investigated using isobaric tags for relative and absolute quantification (iTRAQ) technology. A total of 2406 proteins were identified from the trained and untrained groups. Among these proteins, 147 were differentially expressed, with 87 up-regulated and 60 down-regulated in the trained group compared with the untrained group. These results suggest that the differentially expressed proteins may be involved in the regulation of olfactory learning and memory in A. cerana. The iTRAQ data can provide information on the global protein expression patterns associated with olfactory learning, which will facilitate our understanding of the molecular mechanisms of learning and memory of honeybees.

Transcriptome differences in the hypopharyngeal gland between Western Honeybees (Apis mellifera) and Eastern Honeybees (Apis cerana)

BackgroundApis mellifera and Apis cerana are two sibling species of Apidae. Apis cerana is adept at collecting sporadic nectar in mountain and forest region and exhibits stiffer hardiness and acarid resistance as a result of natural selection, whereas Apis mellifera has the advantage of producing royal jelly. To identify differentially expressed genes (DEGs) that affect the development of hypopharyngeal gland (HG) and/or the secretion of royal jelly between these two honeybee species, we performed a digital gene expression (DGE) analysis of the HGs of these two species at three developmental stages (newly emerged worker, nurse and forager).ResultsTwelve DGE-tag libraries were constructed and sequenced using the total RNA extracted from the HGs of newly emerged workers, nurses, and foragers of Apis mellifera and Apis cerana. Finally, a total of 1482 genes in Apis mellifera and 1313 in Apis cerana were found to exhibit an expression difference among the three developmental stages. A total of 1417 DEGs were identified between these two species. Of these, 623, 1072, and 462 genes showed an expression difference at the newly emerged worker, nurse, and forager stages, respectively. The nurse stage exhibited the highest number of DEGs between these two species and most of these were found to be up-regulated in Apis mellifera. These results suggest that the higher yield of royal jelly in Apis mellifera may be due to the higher expression level of these DEGs.ConclusionsIn this study, we investigated the DEGs between the HGs of two sibling honeybee species (Apis mellifera and Apis cerana). Our results indicated that the gene expression difference was associated with the difference in the royal jelly yield between these two species. These results provide an important clue for clarifying the mechanisms underlying hypopharyngeal gland development and the production of royal jelly.

Polymorphism analysis of csd gene in six Apis mellifera subspecies

The complementary sex determination (csd) gene is the primary gene determining the gender of honey bees (Apis spp). In this study we analyzed the polymorphism of csd gene in six Apis mellifera subspecies. The genomic region 3 of csd gene in these six A. mellifera was cloned, and identified. A total of 79 haplotypes were obtained from these six subspecies. Analysis showed that region 3 of csd gene has a high level of polymorphism in all the six A. mellifera subspecies. The A. m. anatolica subspecies has a slightly higher nucleotide diversity (π) than other subspecies, while the π values showed no significant difference among the other five subspecies. The phylogenetic tree showed that all the csd haplotypes from different A. mellifera subspecies are scattered throughout the tree, without forming six different clades. Population differentiation analysis showed that there are significant genetic differentiations among some of the subspecies. The NJ phylogenetic tree showed that the A. m. caucasica and A. m. carnica have the closest relationship, followed by A. m. ssp, A. m. ligustica, A. m. carpatica and A. m. anatolica that were gathered in the tree in turn.

csd alleles in the red dwarf honey bee (Apis florea, Hymenoptera: Apidae) show exceptionally high nucleotide diversity

Abstract  The single locus complementary sex determination (sl‐csd) gene is the primary gene determining the gender of honey bees (Apis spp.). While the csd gene has been well studied in the Western honey bee (Apis mellifera), and comparable data exist in both the Eastern honey bee (Apis cerana) and the giant honey bee (Apis dorsata), no studies have been conducted in the red dwarf honey bee, Apis florea. In this study we cloned the genomic region 3 of the A. florea csd gene from 60 workers, and identified 12 csd alleles. Analysis showed that similar to A. mellifera, region 3 of the csd gene contains a RS domain at the N terminal, a proline‐rich domain at the C terminal, and a hypervariable region in the middle. However, the A. florea csd gene possessed a much higher level of nucleotide diversity, compared to A. mellifera, A. cerana and Apis dorsata. We also show that similar to the other three Apis species, in A. florea, nonsynonymous mutations in the csd gene are selectively favored in young alleles.

A New Method of Royal Jelly Harvesting Without Grafting Larvae

ABSTRACT: Royal jelly (RJ) is an important bee product and one of the major income sources for beekeepers. For a long time, harvesting royal jelly has largely relied on manually grafting larvae by using grafting needles to remove young (∼1 day old) larvae from a colony to a cell cup. Then, frames of cell cups with the removed brood are placed in productive colonies in a timely manner. Grafting larvae is the first and most difficult step in the process of harvesting RJ. Moreover, the process is time-consuming and labor-intensive. It needs not only effort, but is also restricted by the availability of larvae and the eyesight of the technician. Low efficiency strongly limits the development of royal jelly production. To improve the hardest step in harvesting RJ, we have invented a new method of harvesting royal jelly without grafting larvae. Our results show that the method is feasible and improves the production of royal jelly.