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Background Nutrition and cell size play an important role in the determination of caste differentiation in queen and worker of honeybees (Apis mellifera), whereas the haploid genome dominates the differentiation of drones. However, the effects of female developmental environment on the development of males remain unclear. In this study, young drone larvae were transferred into worker cells (WCs) or remained in drone cells (DCs) to rear drones. The drone larvae were also grafted into queen cells (QCs) for 48 h and then transplanted into drone cells until emerging. Morphological indexes and reproductive organs of these three types of newly emerged drones were measured. Newly emerged drones and third instar drone larvae from WCs, DCs and QCs were sequenced by RNA sequencing (RNA-Seq). Results The amount of food remaining in cells of the QC and WC groups was significantly different to that in the DC group at the early larval stage. Morphological results showed that newly emerged DC drones had bigger body sizes and more well-developed reproductive tissues than WC and QC drones, whereas the reproductive tissues of QC drones were larger than those of WC drones. Additionally, whole body gene expression results showed a clear difference among three groups. At larval stage there were 889, 1761 and 1927 significantly differentially expressed genes (DEGs) in WC/DC, QC/DC and WC/QC comparisons, respectively. The number of DEGs decreased in adult drones of these three comparisons [678 (WC/DC), 338 (QC/DC) and 518 (WC/QC)]. A high number of DEGs were involved in sex differentiation, growth, olfaction, vision, mammalian target of rapamycin (mTOR), Wnt signaling pathways, and other processes. Conclusions This study demonstrated that the developmental environment of honeybee females can delay male development, which may serve as a model for understanding the regulation of sex differentiation and male development in social insects by environmental factors.

9-Oxo-2-decenoic acid (9-ODA, the predominant component of honeybee queen mandibular pheromones) acts as a sex pheromone attracting drones during mating flights in midair. Odorant receptor 11 (Or11), which is located on the membrane of antennal olfaction receptor neurons in bees, can specifically recognize 9-ODA. At present, the molecular pathway of honeybee drones responding to 9-ODA is still unclear. Studies have demonstrated that 9-ODA could downregulate the expression of Kruppel-homolog1 (Kr-h1, a transcription factor related to the regulation of reproduction and division of labor mediated by juvenile hormone) gene in the mushroom of honeybee brain. We speculate that Kr-h1 may be the downstream gene of Or11, which is involved in the pathway of drones responding to 9-ODA. Therefore, we analyzed the influence of 9-ODA on the expression of Or11 and Kr-h1 in the antennae of sexually immature (4 days) and mature (14 days) male honeybees (Apis mellifera) by quantitative polymerase chain reaction (qPCR). The results demonstrated that 9-ODA significantly downregulated the expression of Or11 and Kr-h1 in the antennae of sexually immature and mature drones. Additionally, siRNA-Or11 was injected into the antennae and brain tissues of 8-day-old drone pupae, and the expression patterns of Or11, Kr-h1 and Broad-Complex (Br–c, downstream gene of Kr-h1) were determined by qPCR at 72 h. The RNAi-induced knockdown of Or11 significantly decreased the expression of Or11, Kr-h1 and Br–c in the antennae and brains of drones. This study suggests that the transcription factor Kr-h1 is downstream of Or11, Kr-h1, which may play an important role in the signal transduction process of drones responding to 9-ODA.

The role of the epigenome in phenotypic plasticity is unclear presently. Here we used a multiomics approach (RNA-seq, ChIP-seq, ATAC-seq and Hi-C) to explore the nature of the epigenome in developing honeybee (Apis mellifera) workers and queens. Our data showed that the distinct queen and worker epigenomic landscapes form during the developmental process. Differences in gene expression between workers and queens precede other epigenomic modifications, but the epigenomic differences between workers and queens become more extensive and more layered during development. Genes known to be important for caste differentiation were more likely to be multiply differentially regulated by more than one epigenomic system than other differentially expressed genes. This indicates a multidimensional regulation of expression of key genes, presumably to canalise differences in gene expression. Our data indicate that the epigenome interacts with diverging developmental trajectories rather than controlling them since different epigenomic landscapes form in concert with different developmental outcomes.

Although red clump (RC) stars are easy to identify due to their stability of luminosity and color, about 20-50% are actually red giant branch (RGB) stars in the same location on the HR diagram. In this paper, a sample of 210,504 spectra for 184 318 primary RC (PRC) stars from the LAMOST DR7 is identified, which has a purity of higher than 90 percent. The RC and the RGB stars are successfully distinguished through LAMOST spectra(R~1800 and SNR>10) by adopting the XGBoost ensemble learning algorithm, and the secondary RC stars are also removed. The SHapley Additive exPlanations (SHAP) value is used to explain the top features that the XGBoost model selected. The features are around Fe5270, MgH & MgIb, Fe4957, Fe4207, Cr5208, and CN, which can successfully distinguish RGB and RC stars. The XGBoost is also used to estimate the ages and masses of PRC stars by training their spectra with Kepler labeled asteroseismic parameters. The uncertainties of mass and age are 13 and 31 percent, respectively. Verifying the feature attribution model, we find the age-sensitive elements XGBoost gets are consistent with the literature. Distances of the PRC stars are derived by $K_{S}$ absolute magnitude calibrated by Gaia EDR3, which has an uncertainty of about 6 percent and shows the stars mainly locate at the Galactic disk. We also test the XGBoost with R$\sim$250, which is the resolution of the Chinese Space Station Telescope(CSST) under construction, it is still capable of finding sensitive features to distinguish RC and RGB., 14 pages, 17 figures, accepted by MNRAS

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The distinct honey bee (Apis mellifera) worker and queen castes have become a model for the study of genomic mechanisms of phenotypic plasticity. Prior studies have explored differences in gene expression and methylation during development of the two castes, but thus far no study has performed a genome-wide analysis of differences in RNA processing. To address this here we performed a Nanopore-based direct RNA sequencing with exceptionally long reads to compare the mRNA transcripts between honey bee queen and workers at three points during their larval development. We found thousands of significantly differentially expressed isoforms (DEIs) between queen and worker larvae. Most DEIs contained alternative splicing, and many of them contained at least two types of alternative splicing patterns, indicating complex RNA processing in honey bee caste differentiation. We found a negative correlation between poly(A) length and DEI expression, suggesting that poly(A) tails participate in the regulation of isoform expression. Hundreds of isoforms uniquely expressed in either queens or workers during their larval development, and isoforms were expressed at different points in queen and worker larval development demonstrating a dynamic relationship between isoform expression and developmental mechanisms. These findings show the full complexity of RNA processing and transcript expression in honey bee phenotypic plasticity.

Odorant receptors play a crucial role in the special recognition of scent molecules in the honeybee olfaction system. The odorant receptor 11 (AmOR11) in western honeybee drones (Apis mellifera) has been demonstrated to specifically bind to 9-oxo-2-decenoic acid (9-ODA) of queens. However, little is known regarding the functions of OR11 Asian honeybee drones (Apis cerana) in the context of their mating activities. In this study, the odorant receptor 11 gene (AcOr11) from A. cerana was cloned, and its expression profiles were examined during two developmental stages (immature and sexually mature) and different physiological statuses (flying and crawling). The cDNA sequence of AcOr11 was highly similar to that of AmOr11, and encoded a membrane-coupled protein of 384 amino acids. The results of qRT-PCR indicated that AcOr11 was expressed at higher levels in drone antennae compared to brains, and the expression was significantly up-regulated in sexually mature drone brains compared to immature brains. Interestingly, AcOr11 expression in brains of mature flying drones was dramatically higher than those of mature crawling drones. To our knowledge, this study demonstrate a link between AcOr11 gene expression in the brain of honeybee drones and behavior associated with sexual maturity and mating flight.

In honeybee (Apis mellifera), odorant receptors (Ors) play a crucial role in special recognition of sex pheromones in honeybee mating activities. Four candidate sex pheromone Ors (AmOr10, AmOr11, AmOr18 and AmOr170) have been identified and found to be preferentially expressed in drone antennae. However, few studies have investigated the regulation of these four drone Ors on drone mating behaviour. This study characterised the expression patterns of these Ors across different sexual developmental stages (immature and sexually mature) and different physiological statuses (flying and crawling), using both the antennae and brains of drones. qRT-PCR results indicated that the expression of four Ors were not significantly different in drone antennae between flying and crawling statuses at immature stage. However, all four Ors expression levels in brains of flying drones were significantly higher than those of crawling drones at mature stage. Moreover, only the expression level of Or170 was significantly higher in antennae of mature flying drones than crawling ones. Therefore, this study demonstrated a link between four candidate sex pheromone Ors transcriptional expression in the brains of honeybee drones and behaviour associated with sexual maturity and mating flight. In addition, Or170 might be involved in the maturation of honeybee drones' olfactory system, and in the organisation of odour-mediated mating behaviours.

Background Nutrition and cell size play an important role in the determination of caste differentiation in queen-worker of honeybee (Apis mellifera), whereas the haploid genome dominates the differentiation of drones. However, the effects of female developmental environment on the development of males remain unclear. In this study, young drone larvae were transferred into worker cells (WCs) or remained in drone cells (DCs) to rear drones. The parts of drone larvae were also grafted into queen cells (QCs) for 48 h and then transplanted into drone cells until emerging. Morphological indexes and reproductive organs of these three types of newly emerged drones were measured. Newly emerged drones and 3 d drone larvae from WCs, DCs and QCs were sequenced by RNA sequencing (RNA-Seq). Results Morphological results showed that newly emerged DC drones had bigger body sizes and more well-developed reproductive tissues than WC and QC drones, whereas the reproductive tissues of QC drones were relatively better than those of WC drones. Gene expression results showed a more clear difference among three groups. At the larval stage, there were 889, 1761 and 1927 significantly differentially expressed genes (DEGs) in WC/DC, QC/DC and WC/QC comparisons, respectively. The number of DEGs decreased in adult drones of these three comparisons [678 (WC/DC), 338 (QC/DC) and 518 (WC/QC)]. A high number of DEGs were involved in sex regulation, growth, olfaction, vision, mammalian target of rapamycin (mTOR), Wnt signaling pathways, etc. Weighted gene co-expression network analysis (WCGNA) showed that WC and DC larvae were closer than QC larvae, whereas QC and WC drones were closer than DC drones. These results revealed that DC drones had better development in the body and reproductive system than QC and WC drones. Conclusion This study demonstrated that the developmental environment of honeybee females including the larval diet and cell size delayed male development. Naturally, honeybee colony ovigerous workers in queen-less colonies or non-mated queens produce a large number of dysplasia drones which are not well-developed. Therefore, this study serves as a model for understanding the regulation of sexual differentiation in social insects by environmental factors.

In the eighth data release (DR8) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, more than 318,740 low-resolution stellar spectra with types from B to early F and signal-to-noise ratios >50 were released. With this large volume of the early-type stars, we tried machine-learning algorithms to search for class-one and class-two chemical peculiars (CP1 and CP2), and to detect spectral features to distinguish the two classes in low-resolution spectra. We selected the XGBoost algorithm after comparing the classification efficiency of three machine-learning ensemble algorithms. Using XGBoost followed by the visual investigation, we presented a catalog of 20,694 sources, including 17,986 CP1 and 2708 CP2, in which 6917 CP1 and 1652 CP2 are newly discovered. We also list the spectral features to separate CP1 from CP2 discovered through XGBoost. The stellar parameters (including effective temperature (T eff), surface gravity (log g), metallicity [Fe/H]), the spatial distribution in Galactic coordinates, and the color magnitude were provided for all of the entries of the catalog. The T eff for CP1 distributes from ∼6000 to ∼8500 K, while for CP2 it distributes from ∼7000 to ∼13,700 K. The log g of CP1 ranges from 2.8 to 4.8 dex, peaking at 4.5 dex, and of CP2 it ranges from 2.0 to 5.0 dex, peaking at 3.6 dex, respectively. The [Fe/H] of CP1 and CP2 are from −1.4 to 0.4 dex, and the [Fe/H] of CP1 are on average higher than that of CP2. Almost all of the targets in our sample locate around the Galactic plane.

Fluvalinate has been heavily used to control the pest Varroa destructor and residues in honeybee colony causing long-term exposure threat for bees. But, little is known about the lifetime trips and homing ability of worker bees under fluvalinate stresses during the development period. In this study, honeybees from 2-day-old larvae to 7-day-old adults were continuously fed with different concentrations of fluvalinate (0, 0.5, 5 and 50 mg/kg) and the effects of fluvalinate on the development of larvae were examined. And then, all the treated bees were reintroduced into the original source colony and were monitored, and the homing ability of 20 days old bees at 1000 and 2000 m away from the beehive were tested using the radio frequency identification (RFID). We found that fluvalinate significantly activates the superoxide dismutase (SOD) activities of larvae and 5 mg/kg fluvalinate reduced the homing rate of workers at 2000 m away from colony. 50 mg/kg fluvalinate reduced proportion of capped worker cells, activated Cytochrome P450 (CYP450) activity of larvae, affected the foraging times, influenced the homing rate and homing time of one trip at 2000 m away from colony. Our results showed that the larvae can activate the activities of SOD and detoxification enzymes in detoxification of fluvalinate and reduce the influence on honeybees. But, when the concentration is higher than 5 mg/kg fluvalinate, it is difficult for bees to detoxify fluvalinate completely, which affect the homing rate. The results reflect the potential risk for honeybees in the development stage continuously exposed to fluvalinate.

Honeybees (Apis mellifera) have haplodiploid sex determination: males develop from unfertilized eggs and females develop from fertilized ones. The differences in larval food also determine the development of females. Here we compared the total somatic gene expression profiles of 2-day and 4-day-old drone, queen and worker larvae by RNA-Seq. The results from a co-expression network analysis on all expressed genes showed that 2-day-old drone and worker larvae were closer in gene expression profiles than 2-day-old queen larvae. This indicated that for young larvae (2-day-old) environmental factors such as larval diet have a greater effect on gene expression profiles than ploidy or sex determination. Drones had the most distinct gene expression profiles at the 4-day larval stage, suggesting that haploidy, or sex dramatically affects the gene expression of honeybee larvae. Drone larvae showed fewer differences in gene expression profiles at the 2-day and 4-day time points than the worker and queen larval comparisons (598 against 1190 and 1181), suggesting a different pattern of gene expression regulation during the larval development of haploid males compared to diploid females. This study indicates that early in development the queen caste has the most distinct gene expression profile, perhaps reflecting the very rapid growth and morphological specialization of this caste compared to workers and drones. Later in development the haploid male drones have the most distinct gene expression profile, perhaps reflecting the influence of ploidy or sex determination on gene expression.

Specialised castes are considered a key reason for the evolutionary and ecological success of the social insect lifestyle. The most essential caste distinction is between the fertile queen and the sterile workers. Honey bee (Apis mellifera) workers and queens are not genetically distinct, rather these different phenotypes are the result of epigenetically regulated divergent developmental pathways. This is an important phenomenon in understanding the evolution of social insect societies. Here we studied the genomic regulation of the worker and queen developmental pathways, and the robustness of the pathways by transplanting eggs or young larvae to queen cells. Queens could be successfully reared from worker larvae transplanted up to 3 days age, but queens reared from older worker larvae had decreased queen body size and weight compared to queens from transplanted eggs. Gene expression analysis showed that queens raised from worker larvae differed from queens raised from eggs in the expression of genes involved in the immune system, caste differentiation, body development and longevity. DNA methylation levels were also higher in 3-day queen larvae raised from worker larvae compared to that raised from transplanted eggs identifying a possible mechanism stabilizing the two developmental paths. We propose that environmental (nutrition and space) changes induced by the commercial rearing practice result in a suboptimal queen phenotype via epigenetic processes, which may potentially contribute to the evolution of queen-worker dimorphism. This also has potentially contributed to the global increase in honeybee colony failure rates. This article is protected by copyright. All rights reserved.

International audience; AbstractIn honey bees (Apis mellifera), methyl palmitate (MP), methyl oleate (MO), methyl linoleate (ML), and methyl linolenate (MLN) are important pheromone components of the capping pheromones triggering the capping behavior of worker bees. In this study, we compared the amounts of these four pheromone components in the larvae of workers and drones, prior to be capped, in the process of being capped and had been capped. The amounts of MP, MO, and MLN peaked at the capping larval stage, and ML was highest at capped larvae in worker larvae, whereas in drone larvae, the amounts of the four pheromone components were higher overall and increased with aging. Furthermore, we proposed de novo biosynthetic pathways for MP, MO, ML, and ML, from acetyl-CoA. Besides, stable isotope tracer 13C and deuterium were used to confirm that these capping pheromone components were de novo synthesized by larvae themselves rather than from their diets.

Honey bee foragers must supply their colony with a balance of pollen and nectar to sustain optimal colony development. Inter-individual behavioural variability among foragers is observed in terms of activity levels and nectar vs. pollen collection, however the causes of such variation are still open questions. Here we explored the relationship between foraging activity and foraging performance in honey bees (Apis mellifera) by using an automated behaviour monitoring system to record mass on departing the hive, trip duration, presence of pollen on the hind legs and mass upon return to the hive, during the lifelong foraging career of individual bees. In our colonies, only a subset of foragers collected pollen, and no bee exclusively foraged for pollen. A minority of very active bees (19% of the foragers) performed 50% of the colony’s total foraging trips, contributing to both pollen and nectar collection. Foraging performance (amount and rate of food collection) depended on bees’ individual experience (amount of foraging trips completed). We argue that this reveals an important vulnerability for these social bees since environmental stressors that alter the activity and reduce the lifespan of foragers may prevent bees ever achieving maximal performance, thereby seriously compromising the effectiveness of the colony foraging force.

Queen-worker caste dimorphism is a typical trait for honeybees (Apis mellifera). We previously showed a maternal effect on caste differentiation and queen development, where queens emerged from queen-cell eggs (QE) had higher quality than queens developed from worker cell eggs (WE). In this study, newly-emerged queens were reared from QE, WE, and 2-day worker larvae (2L). The thorax size and DNA methylation levels of queens were measured. We found that queens emerging from QE had significantly larger thorax length and width than WE and 2L. Epigenetic analysis showed that QE/2L comparison had the most different methylated genes (DMGs, 612) followed by WE/2L (473), and QE/WE (371). Interestingly, a great number of DMGs (42) were in genes belonging to mTOR, MAPK, Wnt, Notch, Hedgehog, FoxO, and Hippo signaling pathways that are involved in regulating caste differentiation, reproduction and longevity. This study proved that honeybee maternal effect causes epigenetic alteration regulating caste differentiation and queen development.

Whether a female honey bee (Apis mellifera) develops into a worker or a queen depends on her nutrition during development, which changes the epigenome to alter the developmental trajectory. Beekeepers typically exploit this developmental plasticity to produce queen bee by transplanting worker larvae into queen cells to be reared as queens, thus redirecting a worker developmental pathway to a queen developmental pathway. We studied the consequences of this manipulation for the queen phenotype and methylome over four generations. Queens reared from worker larvae consistently had fewer ovarioles than queens reared from eggs. Over four generations the methylomes of lines of queens reared from eggs and worker larvae diverged, accumulating increasing differences in exons of genes related to caste differentiation, growth and immunity. We discuss the consequences of these cryptic changes to the honey bee epigenome for the health and viability of honey bee stocks.

HighlightAbrupt drought-flood alteration is a frequent meteorological disaster that occurs during summer in southern China and the Yangtze river basin, which often causes a large area reduction of rice yield. We previously reported abrupt drought-flood alteration effects on yield and its components, physiological characteristics, matter accumulation and translocation, rice quality of rice. However, the molecular mechanism of rice yield reduction caused by abrupt drought-flood alternation has not been reported.In this study, four treatments were provided, no drought and no floods (control), drought without floods (duration of drought 10 d), no drought with floods (duration of floods 8 d), and abrupt drought-flood alteration (duration of drought 10 d and floods 8 d). The quantitative analysis of spike metabolites was proceeded by LC-MS (liquid chromatograph-mass spectrometry) firstly. Then the Heat-map, PCA, PLS-DA, OPLS-DA and response ranking test of OPLS-DA model methods were used to analysis the function of differential metabolites (DMs) during the rice panicle differentiation stage under abrupt drought-flood alteration. In addition, relative quantitative analysis of spike total proteins under the treatment was conducted iTRAQ (isobaric tags for relative and absolute quantification) and LC-MS. In this study, 5708 proteins were identified and 4803 proteins were quantified. The identification and analysis of DEPs function suggested that abrupt drought-flood alteration treatment can promote carbohydrate metabolic, stress response, oxidation-reduction, defense response, and energy reserve metabolic process, etc, during panicle differentiation stage. In this study relative quantitative proteomics, metabolomics and physiology data (soluble protein content, superoxide dismutase activity, hydrogen peroxidase activity, peroxidase activity, malondialdehyde content, free proline content, soluble sugar content and net photosynthetic rate) analysis were applied to explicit the response mechanism of rice panicle differentiation stage under abrupt drought-flood alteration and provides a theoretical basis for the disaster prevention and mitigation.AbstractAbrupt drought-flood alternation is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice production. In this study, a quantitative analysis of spike metabolites was conducted via liquid chromatograph-mass spectrometry (LC-MS), and Heat-map, PCA, PLS-DA, OPLS-DA, and a response ranking test of OPLS-DA model methods were used to analyze functions of differential metabolites (DMs) during the rice panicle differentiation stage under abrupt drought-flood alternation. The results showed that 102 DMs were identified from the rice spike between T1 (abrupt drought-flood alternation) and CK0 (control) treatment, 104 DMs were identified between T1 and CK1 (drought) treatment and 116 DMs were identified between T1 and CK2 (flood) treatment. In addition, a relative quantitative analysis of spike total proteins was conducted using isobaric tags for relative and absolute quantification (iTRAQ) and LC-MS. The identification and analysis of DEPs functions indicates that abrupt drought-flood alternation treatment can promote carbohydrate metabolic, stress response, oxidation-reduction, defense response, and energy reserve metabolic process during the panicle differentiation stage. In this study, relative quantitative metabolomics and proteomics analyses were applied to explore the response mechanism of rice panicle differentiation in response to abrupt drought-flood alternation.AbbreviationsCK0no drought and no floodsCK1drought without floodsCK2no drought with floodsT1abrupt drought-flood alterationLC-MSliquid chromatograph-mass spectrometryPCAprinciple component analysis(O)PLS-DA(orthogonal) partial least-squares-discriminant analysisDMsdifferential metabolitesiTRAQisobaric tags for relative and absolute quantificationDEPsdifferentially expressed proteinsKEGGkyoto encyclopedia of genes and genomesGOgene ontologySODsuperoxide dismutaseCAThydrogen peroxidasePODperoxidaseMDAmalondialdehydePnnet photosynthetic rateROSreactive oxygen speciesVIPvariable importance in the projectionFCfold change

Pesticides are considered one of the major contemporary stressors of honey bee health. In this study, the effects of short-term exposure to lambda-cyhalothrin on lifespan, learning, and memory-related characteristics of Apis mellifera were systematically examined. Short-term exposure to lambda-cyhalothrin in worker bees reduced lifespan, affected learning and memory performance, reduced the homing ability, and influenced the expression levels of two learning and memory-related genes of A. mellifera. This research identifies the nature of the sublethal effects of lambda-cyhalothrin on bees and the level of exposure that can be harmful to bee health. This new information will assist in establishing guidelines for the safe use of lambda-cyhalothrin in the field.

In a honey bee colony, worker bees rear a new queen by providing her with a larger cell in which to develop and a large amount of richer food (royal jelly). Royal jelly and worker jelly (fed to developing worker larvae) differ in terms of sugar, vitamin, protein and nucleotide composition. Here we examined whether workers attending queen and worker larvae are separate specialized sub-castes of the nurse bees. We collected nurse bees attending queen larvae (AQL) and worker larvae (AWL) and compared gene expression profiles of hypopharyngeal gland tissues, using Solexa/Illumina digital gene expression tag profiling (DGE). Significant differences in gene expression were found that included a disproportionate number of genes involved in glandular secretion and royal jelly synthesis. However behavioral observations showed that these were not two entirely distinct populations. Nurse workers were observed attending both worker larvae and queen larvae, and there was no evidence of a specialized group of workers that preferentially or exclusively attended developing queens. Nevertheless, AQL attended larvae more frequently compared to AWL, suggesting that nurses sampled attending queen larvae may have been the most active nurses. This study serves as another example of the relationship between differences in gene expression and behavioral specialisation in honey bees.

Cooperative brood care is diagnostic of animal societies. This is particularly true for the advanced social insects and the honey bee is the best understood of the insect societies. A brood pheromone signaling the presence of larvae in a bee colony has been characterised and well studied, but here we explored whether honey bee larvae actively signal their food needs pheromonally to workers. We show that starving honey bee larvae signal to workers via increased production of the volatile pheromone E-β-ocimene. Analysis of volatile pheromones produced by food-deprived and fed larvae with gas chromatography-mass spectrometry showed that starving larvae produced more E-β-ocimene. Behavioural analyses showed that adding E-β-ocimene to empty cells increased the number of worker visits to those cells and similarly adding E-β-ocimene to larvae increased worker visitation rate to the larvae. RNA-seq and qRT-PCR analysis identified 3 genes in the E-β-ocimene biosynthetic pathway that were upregulated in larvae following 30 minutes of starvation and these genes also upregulated in 2-day old larvae compared to 4-day old larvae (2-day old larvae produce the most E-β-ocimene). This identifies a pheromonal mechanism by which brood can beg for food from workers to influence the allocation of resources within the colony.

International audience; The Asian honey bee Apis cerana and the European honey bee Apis mellifera are closely related and morphologically very similar. Where these species coexist, they appear to compete, but the outcomes of competition vary enormously between locations. Here, we report comparative behavioural data for A. cerana and A. mellifera in China gathered by tracking bees using radio frequency identification. Both species organise their division of labour by temporal polyethism and have remarkably similar demographic structure. Analyses of the homing capacities of both species following large-scale displacement suggest that A. mellifera colonies have a larger range than A. cerana. We observed that relocation of A. mellifera to a new environment disrupted colony function for 3 weeks. Our data show that A. mellifera and. A cerana occupy extremely similar behavioural niches, and therefore, the potential for competition between these species is very high.

Honeybee foragers can flexibly adjust their out-hive activities to ensure growth and reproduction of the colony. In order to explore the characteristics of honey bees foraging behaviors, in this study, their flight activities were monitored 24 hours per day for a duration of 38 days, using an radio frequency identification (RFID) system designed and manufactured by the Honeybee Research Institute of Jiangxi Agricultural University in cooperation with the Guangzhou Invengo Information Technology Co., Ltd. Our results indicated that 63.4% and 64.5% of foragers were found rotating more than one day off during the foraging period in two colonies, and 22.5% and 26.4% of the total foraging days were used for rest respectively. Further, although the total foraging time between rotating day-off foragers and continuously working foragers was equal, the former had a significant longer lifespan than the latter. Additionally, the lifespan of the early developed foragers was significantly lower than that of the normally developed foragers. This study enriched the content of foraging behaviors of honey bees, and it could be used as the basis for the further explorations on evolutionary mechanism of foraging behaviors of eusocial insects.

The honeybee is an excellent model organism for research on learning and memory among invertebrates. Learning and memory in honeybees has intrigued neuroscientists and entomologists in the last few decades, but attention has focused almost solely on the Western honeybee, Apis mellifera. In contrast, there have been few studies on learning and memory in the Eastern honeybee, Apis cerana. Here we report comparative behavioral data of color and grating learning and memory for A. cerana and A. mellifera in China, gathered using a Y-maze apparatus. We show for the first time that the learning and memory performance of A. cerana is significantly better on both color and grating patterns than that of A. mellifera. This study provides the first evidence of a learning and memory difference between A. cerana and A. mellifera under controlled conditions, and it is an important basis for the further study of the mechanism of learning and memory in honeybees.