Laboratory culture of the mitesVarroa jacobsoni andTropilaelaps clareae

A laboratory method was developed for rearing the mitesVarroa jacobsoni Oudemans andTropilaelaps clareae Delfinado and Baker to the adult stage. The method consists of infesting larvae ofApis cerana Fabricius andA. mellifera L. with mites in ELISA microtiter racks.     

Grooming behaviour of Apis mellifera syriaca towards Varroa jacobsoni in Jordan

Eight Apis mellifera syriaca colonies at the Jordan University of Science and Technology campus in Jordan were used in the experiments to detect defence behaviour of worker bees against Varroa jacobsoni . This defence mechanism was determined by the degree of damaged mites that dropped from naturally infested colonies on inserts placed under the brood nest from June to October 1998. The average percentage of all dropping mites that were injured was 22.8%. A total of 86.5% of amputated mites were pigmented and 13.5% were less pigmented. Amputation to the first pair of legs was more often seen. Most of the phoretic mites were concealed between sclerites laterally on the abdomen, with distinct preference between second and third tergites. The grooming activity of A. mellifera syriaca provides evidence of active mechanisms of resistance toward the parasitic Varroa -mite.     

Open-air-nesting honey bees Apis dorsata and Apis laboriosa differ from the cavity-nesting Apis mellifera and Apis cerana in brood hygiene behaviour

The cavity-nesting Apis mellifera and Apis cerana bees detect, uncap, and remove diseased brood. The hygiene behaviour of open-air-nesting bees Apis dorsata and Apis laboriosa was investigated in India and Nepal. Sealed A. dorsata pupae were pin-killed or deep-frozen. The workers removed 73 or 37% of damaged pin-killed pupae depending on the diameter of the pins, and only 7% of the frozen undamaged pupae. Migrating A. dorsata and A. laboriosa left unopened the sealed brood in deserted combs. Thus, A. dorsata and A. laboriosa do not open undamaged cells with dead brood. This behaviour is a more efficient mechanism in preventing the spread of diseases and parasitic mites than uncapping and removing dead pupae by A. mellifera and A. cerana. It may be beneficial for migrating A. dorsata and A. laboriosa to temporarily disuse part of the comb cells in exchange for arresting the mites there and thus reducing the increase of their population.     

Natural selection of Varroa jacobsoni explains the different reproductive strategies in colonies of Apis cerana and Apis mellifera

In colonies of European Apis mellifera, Varroa jacobsoni reproduces both in drone and in worker cells. In colonies of its original Asian host, Apis cerana, the mites invade both drone and worker brood cells, but reproduce only in drone cells. Absence of reproduction in worker cells is probably crucial for the tolerance of A. cerana towards V. jacobsoni because it implies that the mite population can only grow during periods in which drones are reared. To test if non-reproduction of V. jacobsoni in worker brood cells of A. cerana is due to a trait of the mites or of the honey-bee species, mites from bees in A. mellifera colonies were artificially introduced into A. cerana worker brood cells and vice versa. Approximately 80% of the mites from A. mellifera colonies reproduced in naturally infested worker cells as well as when introduced into worker cells of A. mellifera and A. cerana. Conversely, only 10% of the mites from A. cerana colonies reproduced, both in naturally infested worker cells of A. cerana and when introduced into worker cells of A. mellifera. Hence, absence of reproduction in worker cells is due to a trait of the mites. Additional experiments showed that A. cerana bees removed 84% of the worker brood that was artificially infested with mites from A. mellifera colonies. Brood removal started 2 days after artificial infestation, which suggests that the bees responded to behaviour of the mites. Since removal behaviour of the bees will have a large impact on fitness of the mites, it probably plays an important role in selection for differential reproductive strategies. Our findings have large implications for selection programmes to breed less-susceptible bee strains. If differences in non-reproduction are mite specific, we should not only look for non-reproduction as such, but for colonies in which non-reproduction in worker cells is selected. Hence, in selection programmes fitness of mites that reproduce in both drone and worker cells should be compared to fitness of mites that reproduce only in drone cells. © Rapid Science Ltd. 1998     

安徽省七种蜜蜂病毒的发生与流行研究

【目的】调查安徽省内7种常见蜜蜂病毒:蜜蜂畸翅病毒(Deformed wing virus,DWV)、以色列急性麻痹病毒(Israeli acute paralysis virus,IAPV)、急性蜜蜂麻痹病毒(Acute bee paralysis virus,ABPV)、慢性麻痹病毒(Chronic bee paralysis virus,CBPV)、黑蜂王台病毒(Black queen cell virus,BQCV)、囊状幼虫病病毒(Sacbrood virus,SBV)、克什米尔病毒(Kashmir bee virus,KBV)的感染发生情况,为安徽养蜂业可持续健康发展提供理论依据。【方法】运用反转录RT-PCR和序列分析比对的方法对安徽省内21个乡镇中的38个蜂场蜜蜂样品进行研究分析,以获得以上7种蜜蜂病毒的特异性发生情况。【结果】意大利蜜蜂Apis mellifera蜂场感染率:DWV(64%),IAPV(43%),CBPV(32%),ABPV(14%),BQCV(11%);中华蜜蜂Apis cerana蜂场感染率:DWV(80%),IAPV(40%),CBPV(30%),ABPV(10%),BQCV(0)。SBV和KBV在所有的蜜蜂样品中均未检测到。【结论】DWV,IAPV,CBPV,ABPV,BQCV在安徽省内大范围都存在发生流行现象,SBV和KBV对安徽蜜蜂的潜在危害可能性小。     

中华蜜蜂与意大利蜜蜂蜂王体表信息素含量比较

【目的】分析中华蜜蜂Apis cerana cerana与意大利蜜蜂Apis mellifera ligustica蜂王不同时期的体表信息素含量变化,探索两蜂种之间蜂王交尾干扰机理。【方法】本试验通过GC-MS检测并分析了中华蜜蜂蜂王和意大利蜜蜂蜂王刚出房、性成熟时期以及婚飞过程中体表信息素含量变化。【结果】研究结果表明:中华蜜蜂性成熟蜂王在飞行过程中,其体表9-ODA含量显著高于刚出房蜂王,9-HDA显著高于刚出房蜂王和性成熟蜂王;意大利蜜蜂飞行蜂王在9-ODA含量也显著高于刚出房蜂王。另外,意大利蜜蜂性成熟期蜂王在9-ODA、9-HDA、10-HDA含量显著高于中华蜜蜂蜂王,而两蜂种蜂王体表信息素在婚飞时期差异不显著。【结论】同种蜂王不同发育时期,其体表信息素含量存在差异;中华蜜蜂蜂王与意大利蜂王在婚飞过程中,其体表信息素差异不显著,但部分体表信息素在性成熟而未进行婚飞时差异显著。     

Relationship of the neutral sterols and ecdysteroids of the parasitic mite,Varroa jacobsoni to those of the honey bee,Apis mellifera

The neutral sterols of the parasitic mite Varroa jacobsoni were compared with Apis mellifera carnica drone pupae. Analysis by GLC-mass spectrometry indicated mite sterols were reflective of the sterol composition of the drones; 24-methylenecholesterol was the major sterol in both species, with lesser amounts of sitosterol and isofucosterol. Cholesterol accounted for less than 1% of the total sterols. Ecdysteroid analyses indicated drones contained primarily makisterone A. In addition to makisterone A, mites contained ecdysone and 20-hydroxyecdysone, which accounted for over 66% of the ecdysteroid detected. These results indicate that while V. jacobsoni are apparently unable to convert dietary sterols to cholesterol, they are able to produce significant amount of C(27) ecdysteroids in a low cholesterol environment.     

温度对中华蜜蜂和意大利蜜蜂个体主要抗寒生理指标的影响

【目的】为了探究中华蜜蜂Apis cerana cerana和意大利蜜蜂Apis mellifera ligustica个体耐寒性差异的生理机制。【方法】本试验分别对20日龄的中华蜜蜂和意大利蜜蜂工蜂进行0、10、25℃持续4 h的温度处理,随后测定不同温度处理后两蜂种体内葡萄糖、甘油和氨基酸的含量。【结果】低温状态下中华蜜蜂体内葡萄糖含量显著降低,意大利蜜蜂在0℃组显著下降却在10℃组显著上升;中华蜜蜂体内甘油在低温环境下显著积累,意大利蜜蜂体内甘油水平在10℃时显著的上调却在0℃组无显著变化;中华蜜蜂体内17种氨基酸在各温度处理间显著变化,且多数的氨基酸含量表现出10℃组降低而0℃组积累的趋势,意大利蜜蜂体内只有15种氨基酸参与机体的抗寒机制,其中多数的氨基酸表现为低温环境下大量积累,仅有亮氨酸和精氨酸表现为低温时被转化消耗的现象。【结论】低温条件下可引起两蜂种体内葡萄糖、甘油和氨基酸含量的显著变化,初步推测蜜蜂体内可能存在"葡萄糖-甘油-氨基酸"的抗寒物质系统,但两蜂种在不同程度的低温处理后各生理指标的变化存在较大的差异,从一定程度上阐释两蜂种抗寒性的差异。本研究为蜜蜂个体抗寒生理机制的进一步研究提供基础数据,同时为蜜蜂抗寒新品系的选育提供理论依据。     

中蜂与意蜂无王群培育非自身蜂种蜂子及改造王台特性

以中华蜜蜂和意大利蜜蜂为试验材料,通过组织相应无王群,把一蜂种无王群中的子脾加入到另一蜂种无王群中,进行中蜂和意蜂无王群培育非自身蜂种蜂子和改造王台特性研究,当未培育出蜂王时,分别从原有王群中调入子脾进行第2、第3期试验。结果表明:中蜂无王群中的工蜂会清除引入意蜂子脾中的蜂卵,但随着引入意蜂子脾封盖子羽化出房的意蜂幼蜂数量增加而逐渐接受意蜂幼虫,蜂群未改造意蜂王台,只培育出中蜂蜂王;意蜂无王群中的工蜂会随着引入中蜂子脾中羽化出房的中蜂幼蜂数量增加而逐渐接受中蜂卵及幼虫,并从第2期试验开始会改造中蜂王台,但最终只培育出意蜂蜂王。     

西方蜜蜂对东方蜜蜂采集行为及食物资源利用的影响

【目的】在云南省腾冲市界头镇油菜花期,比较西方蜜蜂Apis mellifera L.不同放蜂密度下东方蜜蜂Apis cerana F.采集行为和对食物资源利用的变化,以期从食物资源竞争的角度为合理保护我国本土蜂种和维持植物群落结构及其稳定性提供科学依据。【方法】以界头镇为研究区域,在油菜花期根据西方蜜蜂的蜂场分布、蜂群数量及放蜂密度,确定了三个样点两种生境,观察西方蜜蜂不同放蜂密度下对东方蜜蜂的采集行为、访花频率、单花采集停留时间及粉源植物利用的影响。【结果】在农田生境中,西方蜜蜂放蜂密度最大的沙坝地试验点东方蜜蜂的访花频率最高(14.93朵/min),单花采集停留时间最短(1.96 s/朵),采集油菜花粉的数量比例最低(37%),采集花粉的种类最多(11种植物),与放蜂密度最小的新庄试验点相比,上述指标差异均显著。在山林生境中,西方蜜蜂放蜂密度最小的新庄试验点,东方蜜蜂的访花频率最低(8.48朵/min),单花采集停留时间最长(4.55 s/朵),采集油菜花粉的数量比例最高(33%),采集花粉的种类最少(8种植物),与放蜂密度最大的沙坝地试验点相比,上述指标差异均显著。【结论】在两种生境下,西方蜜蜂放蜂密度对东方蜜蜂采集行为和粉源植物利用均有显著影响,西方蜜蜂放蜂密度越大,东方蜜蜂对大宗蜜源植物(油菜)花粉的采集量越少,其采集区域由农田向山林转移的趋势越明显。     

Perizin, an acaricide to combat the mite Varroa jacobsoni: its distribution in and influence on the honeybee Apis mellifera

Abstract. The distribution of coumaphos (the active component of perizin), fed to individual honeybees, in the honey stomach, haemolymph, midgut and rectum was studied over time. Concurrently, we investigated changes occurring in the haemolymph volume due to the ingestion of perizin, and we examined the influence of a Nosema apis infection on the survival of bees that had been fed perizin. The maximum amount of coumaphos in the haemolymph was found 4h after ingestion, but it was only 2–3% of the total amount recovered. After 15 min 55% of the total amount of the coumaphos recovered was in the honey stomach and available for distribution within the colony by trophallaxis, while 45% had already passed the proventriculus. Ultimately the coumaphos accumulated in the rectum. The volume of the haemolymph significantly increased in bees which were fed perizin compared with bees which were fed syrup and with non-fed bees. The lethal dose of coumaphos to 3-day-old bees was three times higher than the lethal dose for 18- and 1-day-old bees. The number of Nosema apis spores in the alimentary canal was not correlated with the survival of the bees that were fed perizin. It is concluded that coumaphos can act as a systemic agent and can be distributed to other individuals in a colony through trophallaxis, but these effects are limited to a maximum period of 12h after ingestion.     

Discriminant conditioning of foragers in the Asian honey bees Apis cerana and A.dorsata

Abstract.

• 1 Nectivore foraging environments are typically modelled as choices among non-fluctuating rewards, but in reality they often consist of intermittent daily nectar and pollen sources. Intermittent rewards create two distinct foraging problems for colonial nectivores: re-recruitment (periodically returning to intermittent rewards) and re-allocation (finding new rewards).
• 2 The role of scent in learning and remembering the locations of discontinuous nectar rewards was examined by testing re-recruitment efficiency of Apis cerana and A.dorsata to reward-correlated scents (odour discriminant self-conditioning). Experiments examined the responses of non-naive foragers to an odour correlated with prior reward, and to odours not correlated with prior rewards, by placing different scents into a colony and observing the number of bees re-recruited to a feeding station.
• 3 Re-recruitment of non-naive foragers in both species was significantly greater in response to the conditioning scent than to the experimental controls. However, species behaviour differed in one aspect; re-recruited A.cerana foragers landed on the feeding station when unscented reward was offered, whereas re-recruited A.dorsata foragers returned but would not land without conditioning scent present in the reward.

     

Some observations on the concurrent parasitization ofApis florea byTropilaelaps clareae andEuvarroa sinhai

Adult bees, worker brood cells and drone brood cells ofApis florea were examined for the presence of mites by stereo microscope and by washing with soap. Tropilaelaps clareae was only found on adult bees;Euvarroa sinhai on adult bees and drone brood. The level ofT. clareae infestation is always very low, generally not exceeding 0.1%; that ofE. sinhai is somewhat higher. The mites were never found together on a single bee.     

Spatial memory, navigation and dance behaviour in Apis mellifera

Navigation and dance communication in Apis mellifera have been extensively studied on the level of sensory processing, but the structure and content of the spatial memory underlying such phenomena have yet to be addressed. Here we survey new findings indicating that the memory used by bees to navigate within the range of their orientation flights is much more complex than hitherto thought. It appears to allow them to decide between at least two goals in the field, and to steer towards them over considerable distances. Two models concerning the structure of bees’ spatial memory are developed from new empirical evidence. The first one relies on the integration of at least two flight vectors, while the second assumes the existence of a ‘functional’ map based on the information available on-site. These findings also raise questions about the process of encoding and decoding information in the context of the waggle dance. We review published data and recent evidence indicating that memories of topographical features might also be involved in dance communication, and point out what needs to be addressed to elucidate the corresponding memory demands. The flight paths of recruited bees can now be traced by means of radar techniques, and thus tools are available to tackle these questions.     

Structural and functional differences in the antennal olfactory system of worker honey bees of Apis mellifera and Apis cerana

Olfactory cues are important sensory modalities on individual discrimination, perception, and efficient orientation to food sources in most insects. In honey bees, which are well known as eusocial insects, olfactory cues are mainly used to maintain a colony. Although much research has been reported on olfactory systems in honey bee olfaction, little is known about the differences between two major honey bee species, the European honey bee Apis mellifera and the Asian honey bee Apis cerana. In order to understand the differences of olfactory characteristics in the two species, we compared the distribution of sensory hairs on the antennae and antennal olfactory responses, using electron microscopy, electrophysiological recording and molecular expression level of odorant receptors. Our present study demonstrated that the antennae of A. cerana have more olfactory sensilla than A. mellifera, responding more strongly to various floral volatile compounds. At the molecular level, olfactory co-receptor (Orco), which makes heterodimers with other conventional olfactory receptors, is more abundantly expressed in the antenna of A. cerana than of A. mellifera. These findings extend our understanding of the olfactory systems and behavioral responses to various ecological and biological signals in two closely related honey bee species.     

Pyrosequencing analysis of the bacterial communities in the guts of honey bees Apis cerana and Apis mellifera in Korea

The bacterial communities in the guts of the adults and larvae of the Asian honey bee Apis cerana and the European honey bee Apis mellifera were surveyed by pyrosequencing the 16S rRNA genes. Most of the gut bacterial 16S rRNA gene sequences were highly similar to the known honey bee-specific ones and affiliated with Pasteurellaceae or lactic acid bacteria (LAB). The numbers of operational taxonomic units (OTUs, defined at 97% similarity) were lower in the larval guts (6 or 9) than in the adult guts (18 or 20), and the frequencies of Pasteurellaceae-related OTUs were higher in the larval guts while those of LAB-related OTUs in the adult guts. The frequencies of Lactococcus, Bartonella, Spiroplasma, Enterobacteriaceae, and Flavobacteriaceae-related OTUs were much higher in A. cerana guts while Bifidobacterium and Lachnospiraceae-related OTUs were more abundant in A. mellfera guts. The bacterial community structures in the midguts and hindguts of the adult honey bees were not different for A. cerana, but significantly different for A. mellifera. The above results substantiated the previous observation that honey bee guts are dominated by several specific bacterial groups, and also showed that the relative abundances of OTUs could be markedly changed depending on the developmental stage, the location within the gut, and the honey bee species. The possibility of using the gut bacterial community as an indicator of honey bee health was discussed.     

T-RFLP analysis of bacterial communities in the midguts of Apis mellifera and Apis cerana honey bees in Thailand

This study investigated bacterial community structures in the midguts of Apis mellifera and Apis cerana in Thailand to understand how bacterial communities develop in Apis species. The bacterial species present in replicate colonies from different locations and life stages were analysed. PCR amplification of bacterial 16S rRNA gene fragments and terminal restriction fragment length polymorphism analyses revealed a total of 16 distinct terminal restriction fragments (T-RFs), 12 of which were shared between A. mellifera and A. cerana populations. The T-RFs were affiliated to Beta- and Gammaproteobacteria, Firmicutes and Actinomycetes. The Gammaproteobacteria were found to be common in all stages of honey bee, but in addition, the Firmicutes group was found to be present in the worker bees. Bacterial community structure showed no difference amongst the replicate colonies, but was affected to some degree by geographical location, life stage and species of honey bees.     

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

Background

Apis 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).

Results

Twelve 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.

Conclusions

In 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.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-744) contains supplementary material, which is available to authorized users.     

Time-activity budgets and space structuring by the different life stages ofVarroa jacobsoni in capped brood of the honey bee,Apis mellifera

Varroa jacobsoni reproduces in honey bee brood cells. Here the behavioral activity and use of space by infestingVarroa females and progeny were quantified in transparent artificial brood cells. The time-activity budget of both infesting and developing mites converged toward a stable pattern which was established during the bee prepupal stage of the infesting mites and the protonymphal stage of mite progeny. The pattern was such that infesting females and offspring eventually divided their activity between the fecal accumulation on the cell wall, which served as the rendezvous site for newly molted individuals, and the feeding site prepared on the pupa by the foundress. Other parts of the cell wall were used for oviposition and molting, away from the fecal accumulation on which activity of mobile stages was concentrated. Space structuring and the time-activity budget inVarroa probably evolved to enhance the number of fertilized females produced within the capped brood, where space and time are limiting factors. These behavioral adaptations parallel those of other mite species which show group behavior within cavities.     

The sex determination gene shows no founder effect in the giant honey bee, Apis dorsata

Background

All honey bee species (Apis spp) share the same sex determination mechanism using the complementary sex determination (csd) gene. Only individuals heterogeneous at the csd allele develop into females, and the homozygous develop into diploid males, which do not survive. The honeybees are therefore under selection pressure to generate new csd alleles. Previous studies have shown that the csd gene is under balancing selection. We hypothesize that due to the long separation from the mainland of Hainan Island, China, that the giant honey bees (Apis dorsata) should show a founder effect for the csd gene, with many different alleles clustered together, and these would be absent on the mainland.

Methodology/Principal Findings

We sampled A. dorsata workers from both Hainan and Guangxi Provinces and then cloned and sequenced region 3 of the csd gene and constructed phylogenetic trees. We failed to find any clustering of the csd alleles according to their geographical origin, i.e. the Hainan and Guangxi samples did not form separate clades. Further analysis by including previously published csd sequences also failed to show any clade-forming in both the Philippines and Malaysia.

Conclusions/Significance

Results from this study and those from previous studies did not support the expectations of a founder effect. We conclude that because of the extremely high mating frequency of A. dorsata queens, a founder effect does not apply in this species.