In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources.

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Although the phylogenetic relationships of Apis species (Hymenoptera: Apidae) have been generally accepted, genetic variation within most species and some new possible species' status have not been studied in detail. In this study, we surveyed the genetic variation of mitochondrial DNA sequences in Apis species from China and investigated the phylogeography of Apis dorsata F. in China and neighboring Asian areas. The phylogeny of Chinese Apis species was consistent with the generally accepted Apis phylogeny, and a substructure within A. dorsata was suggested. Furthermore, results of analysis of molecular variance revealed significant genetic structuring of A. dorsata between Hainan Island and China mainland. When compared with neighboring Asian areas, Chinese A. dorsata grouped with one A. dorsata sample from Palawan Island of Philippines and two samples from Malaysia. Another two samples from Malaysia clustered with one Nepalese sample and the cluster from Thailand also was supported. These results support the hypothesis that glaciations and deglaciations during the Pleistocene could have greatly influenced the distribution and divergence of A. dorsata in China and Southeast Asia. In addition, the species status of Apis dorsata breviligula Maa and Apis dorsata binghami Cockerell were supported in our study and genetic variation may exist in Apis laboriosa Smith despite of limited natural distribution.

Apis cerana cerana has the biological characteristic of gnawing off the old brood cells which reared multiple generations of workers. This study investigated the internal structure of newly built, old, and semi-rebuilt brood cells and their effects on the morphological development of workers to understand the significance of Apis cerana cerana gnawing off the old brood cells. The results showed that there was no significant difference among the three diameters (at the top, middle, and bottom positions) of newly built or semi-rebuilt brood cells (P > 0.05), but these changed within the old brood cells (P < 0.05). The top, middle, or bottom diameters of the newly built and semi-rebuilt brood cells were significantly larger than those of the old brood cells (P < 0.05), but were almost the same between the newly built and the semi-rebuilt brood cells (P > 0.05). The weight and base thickness of the cocoon were significantly greater in the old brood cells than those in the semi-rebuilt brood cells (P < 0.05). Importantly, the birth weight, body length, and the tested six external morphological indices did not show a significant difference between the newly built and semi-rebuilt brood cells (P > 0.05) but were significantly larger than those of old brood cells (P < 0.05). The size of the brood cell and the external morphology of the workers showed a positive correlation. This study highlights the significance of Apis cerana cerana gnawing off the old brood cells providing a reference for its scientific rearing.

The hexagonal structure of the honey bee comb cell has been the source of many studies attempting to understand its structure and function. In the storage area of the comb, only honey is stored and no brood is reared. We predicted that honey bees may construct different hexagonal cells for brood rearing and honey storage. We used quantitative analyses to evaluate the structure and function of the natural comb cell in the Chinese bee, Apis cerana cerana and the Italian bee, A. mellifera ligustica. We made cell molds using a crystal glue solution and measured the structure and inclination of cells. We found that the comb cells of A. c. cerana had both upward-sloping and downward-sloping cells; while the A. m. ligustica cells all tilted upwards. Interestingly, the cells did not conform to the regular hexagonal prism structure and showed irregular diameter sizes. In both species, comb cells also were differentiated into worker, drone and honey cells, differing in their diameter and depth. This study revealed unique differences in the structure and function of comb cells and showed that honey bees design their cells with precise engineering to increase storage capacity, and to create adequate growing room for their brood.

There have been many population-based genomic studies on human-managed honeybees (Apis mellifera and Apis cerana), but there has been a notable lack of analysis with regard to wild honeybees, particularly in relation to their evolutionary history. Nevertheless, giant honeybees have found to occupy distinct habitats and display have remarkable characteristics, which are attracting an increase amount of attention. In this study, we de novo sequenced and then assembled the draft genome sequence of the Himalayan giant honeybee, Apis laboriosa. Phylogenetic analysis based on genomic information indicated that A. laboriosa and its tropical sister species Apis dorsata diverged ∼2.61 million years ago, which supports the speciation hypothesis that link A. laboriosa to geological changes throughout history. Furthermore, we re-sequenced A. laboriosa and A. dorsata samples from five and six regions, respectively, across their population ranges in China. These analysis highlighted major genetic differences for Tibetan A. laboriosa as well as the Hainan Island A. dorsata. The demographic history of most giant honeybee populations has mirrored glacial cycles. More importantly, contrary to what has occurred among human-managed honeybees, the demographic history of these two wild honeybee species indicates a rapid decline in effective population size in the recent past, reflecting their differences in evolutionary histories. Several genes were found to be subject to selection, which may help giant honeybees to adapt to specific local conditions. In summary, our study sheds light on the evolutionary and adaptational characteristics of two wild giant honeybees species, which was useful for giant honeybee conservation.

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The sequences of mitochondrial ND2, CO2, and 16S rRNA genes and nuclear ITPR gene were obtained from 22 samples of 5 Apis species from China. The characteristics of the sequences and the pairwise distances among species were analyzed. Phylogenetic trees were reconstructed for Apis species using maximum parsimony, neighbor-joining and maximum likelihood methods together with the sequences of the other 4 Apis species downloaded from GenBank. Results supported that Apis species were divided into three major clusters: dwarf bees (A. florea and A. andreniformis), giant bees (A. dorsata and A. laboriosa), and cavity-nesting bees (A. mellifera, A. cerana, A. koschevnikovi, A. nigrocinta, and A. nuluensis). The dwarf honey bees were confirmed as basal lineage. Our study also revealed a high level of genetic divergence between A. dorsata from Hainan Island and China mainland.