Drone “quality” and caste interactions in the honey bee, Apis mellifera L.

We investigated the influence of drone size and potential reproductive quality on caste interactions by adding large drones reared in drone cells (DC drones; considered to be of higher quality) and small drones reared in worker cells (WC drones; of lower quality) to two observation colonies and monitoring worker–drone interactions and acceptance by workers. When initially introduced into the colonies more DC drones received trophallaxis, whereas more WC drones received aggression and eviction attempts from workers. Nevertheless, WC and DC drones were equally likely to be accepted by workers. For both drone types accepted individuals had slightly, but significantly greater weights than rejected males. Thus, workers discriminated between drones of different sizes and potential quality upon initial encounter, although these discriminations were not strongly associated with acceptance decisions. After drones were accepted, workers either showed no preference for interacting with WC or DC drones, or if a preference was shown it tended to favor WC drones. Compared to accepted DC drones, significantly more WC drones received grooming for longer periods of time and also spent more time engaged in all interactions with workers combined. DC and WC drones did not differ in the likelihood of receiving trophallaxis or the vibration signal, although for both interactions slightly more WC drones were recipients. Thus, workers may bias some interactions with accepted drones to favor smaller individuals with potential developmental deficiencies, in a manner that could contribute to the production of a greater total number of competitive males and increased colony reproductive output.     

Decreased flight performance and sperm production in drones of the honey bee (Apis mellifera) slightly infested by Varroa destructor mites during pupal development

We developed a bioassay to measure the flying power of drone, in order to determine which drones could reach a drone congregation area. A wind tunnel was used to test unparasitized drones and drones slightly parasitized by one or two mites during pupal development, and counts were made of the number of spermatozoa that they produced. Drones parasitized with one mite flew as long as control drones (x= 6'55" and 6'48", respectively, P = 0.512); however, those that had been infested by two mites flew significantly less (x= 2'16", P<0.001). There was a significant positive correlation (P<0.01) between flight duration and the number of spermatozoa per drone in control group (r = 0.53), and in both the one mite (r = 0.43) and two mite (r = 0.54) groups. Drones infested during development with one or two mites produced 24 and 45% fewer sperm, respectively.     

Deformed wing virus in western honey bees (Apis mellifera) from Atlantic Canada and the first description of an overtly-infected emerging queen

Deformed wing virus (DWV) in western honey bees (Apis mellifera) often remains asymptomatic in workers and drones, and symptoms have never been described from queens. However, intense infections linked to parasitism by the mite Varroa destructor can cause worker wing deformity and death within 67 h of emergence. Ten workers (eight with deformed wings and two with normal wings) and three drones (two with deformed wings and one with normal wings) from two colonies infected with V. destructor from Nova Scotia, Canada, and two newly-emerged queens (one with deformed wings and one with normal wings) from two colonies infected with V. destructor from Prince Edward Island, Canada, were genetically analyzed for DWV. We detected DWV in all workers and drones, regardless of wing morphology, but only in the deformed-winged queen. This is the first report of DWV from Atlantic Canada and the first detection of a symptomatic queen with DWV from anywhere.     

Discrimination of nestmate workers and drones in honeybees

Summary Discrimination of nestmates from non-nestmates has mainly been investigated in female social insects. Little is known about discrimination of males. Here we show that under natural conditions at the nest entrance, honeybee workers can discriminate nestmate drones from non-nestmate drones as effectively as they can discriminate nestmate workers from non-nestmate workers.     

Mimicking a Honeybee Queen?Vespa affinis indosinensis Pérez 1910 Hunts Drones of Apis cerana F. 1793

Hornets (Vespa affinis) flying in a drone congregation area attracted drones of Apis cerana. The drones followed the hornet and were ‘manoeuvred’ towards a leaf or a tree. The hornet then rushed at one of the drones. Many attempts by the hornet to catch a drone were unsuccessful and all drones fled. After failing, the hornet returned to centre of the drone congregation area and repeated the behaviour. Only after successfully seizing of a drone did the hornet leave the drone congregation area carrying its prey. In a two-choice test in the centre of the drone congregation area, free-flying A. cerana drones preferred a hornet model to a live A. cerana queen. V. affinis apparently ‘exploits’ the intraspecific communication between queen and drones of A. cerana. Hunting of drones in the drone congregation area by V. affinis may be an example of predatory mimicry.     

Genetic structure of drone congregations of the stingless bee Scaptotrigona mexicana

Drones of stingless bee species often form distinctive congregations of up to several hundred individuals which can persist over considerable periods of time. Here we analyse the genetic structure of three drone congregations of the neotropical stingless bee Scaptotrigona mexicana employing eight microsatellite markers. Two congregations were close to each other (50 m), the third one was located more than 10 km away from them. This spatial pattern was also reflected on the genetic level : the two close congregations did not show any population sub-structuring, whereas the more distant congregation showed a significant population differentiation to both of them. Population subdifferentiation was however low with F _st values (F _st = 0.020 and 0.014) between the distant congregations, suggesting gene flow over larger distances mediated by the drones of S. mexicana. Based on the genotypic data we also estimated the number of colonies contributing drones to the congregations. The two joint congregations consisted of drones originating from 39,6 colonies, while the third congregation was composed of drones from 21,8 colonies, thus proving that congregations of S. mexicana are constituted of unrelated drones of multicolonial origin. Received 23 April 2007; revised 21 September 2007; accepted 2 October 2007.     

Caste, Sex and Strain of Honey Bees (Apis mellifera) Affect Infestation with Tracheal Mites (Acarapis woodi)*

Worker honey bees from genetic strains selected for being resistant (R) or susceptible (S) to tracheal mites typically show large differences in infestation in field colonies and in bioassays that involve controlled exposure to infested bees. We used bioassays exposing newly emerged individuals to infested workers to compare the propensity for tracheal mites to infest queens, drones and workers from R and S colonies. In tests with queens, newly emerged R and S queens were either simultaneously confined in infested colonies (n = 95 and 87 respectively), or individually caged with groups of 5–20 infested workers (n = 119 and 115 respectively). Mite prevalence (percentage of individuals infested) and abundance (foundress mites per individual) after 4–6 days did not differ between R and S queens. In another test, five newly emerged drones and workers from both an R and an S colony, and a queen of one of the two strains, were caged in each of 38 cages with 20 g of workers infested at 60–96% prevalence. Infestations of the R queens (n = 17) and S queens (n = 19) did not differ significantly, but R workers had half the mite abundance of S workers, while R drones received about a third more migrating mites than S drones. In tests to evaluate possible mechanisms, removal of one mesothoracic leg from R and S workers resulted in 2- to 10-fold increase in mite abundance on the treated side, but excising legs did not affect infestation of the corresponding tracheae in drones. This suggests that differences in infestation between R and S workers, but not drones, are largely determined by their ability to remove mites through autogrooming. If autogrooming is the primary mechanism of colony resistance to tracheal mites, selection for resistance to tracheal mites using infestation of hemizygous drones may be inefficient. *The U.S. Government’s right ot retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Die spektrale Empfindlichkeit einzelner Sehzellen des Bienenauges

Zusammenfassung In einzelne Sehzellen der Fazettenaugen von Bienenarbeiterinnen und Drohnen werden Mikroelektroden eingestochen; die bei Belichtung mit quantengleichen monochromatischen Lichtern im Bereich von 318–650 nm auftretenden intrazellulär abgeleiteten Rezeptorpotentiale werden gemessen.Die relativen spektralen Empfindlichkeitskurven einzelner Sehzellen werden bestimmt.Bei Drohnen finden sich drei Arten von Sehzellen mit verschiedener spektraler Empfindlichkeit; die Maxima liegen bei 340, 450 und 530 nm. Sehzellen mit dem Maximum der Empfindlichkeit bei 530 nm wurden bisher nur im äußersten ventralen Augenbezirk gefunden. Es ist möglich, aber nicht sicher, daß bei Drohnen Sehzellen mit einem Maximum der Empfindlichkeit bei oder unterhalb 318 nm vorkommen.Bei Bienenarbeiterinnen liegen die Maxima der Empfindlichkeit bei 340, 430, 460, 530 nm.Empfindlichkeitskurven mit mehr als einem Maximum werden als Artefakte gedeutet, da sie keine reproduzierbare Form haben.Die gemessenen Empfindlichkeitskurven stimmen mit den Absorptionskurven von Retinin-haltigen Sehfarbstoffen entsprechender Maxima überein.Der Verlauf der gemessenen Empfindlichkeitskurven entspricht dem Farbunterscheidungsvermögen der Bienen, wie es aus Verhaltensversuchen bekannt ist.

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Summary Microelectrodes were inserted in single visual cells of the compound eyes of honey-bee workers and drones. The eyes were exposed to monochromatic lights of equal quanta between 318 and 650 nm and intracellular receptor potentials were recorded.The relative spectral sensitivity curves of single visual cells were determined.In drones three types of visual cells with different spectral sensitivity were found, with the maxima at about 340, 450 and 530 nm. Visual cells with maximum sensitivity at 530 nm were found to date only in the extreme ventral region of the eye. It is possible, though not certain, that in drones there are visual cells with a maximum sensitivity at or below 318 nm.In honey-bee workers the sensitivity maxima lie at about 340, 430, 460 and 530 nm.Sensitivity curves with more than one maximum are interpreted as artefacts since their forms are not reproducible.The sensitivity curves reflect quite accurately the absorption curves of corresponding maxima for visual pigments containing retinene.The course of the sensitivity curves agrees well with the colour discrimination of honey-bees as has been shown in behavioural experiments.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Further characterization of nuclear DNA RFLP markers that distinguish African and European honeybees

Two nuclear honeybee DNA probes, 12R1C1 and 2A2, were reported previously to detect restriction fragment patterns specific to African and neotropical African honeybee populations. Individual drones and workers from several additional Old and New World populations, African and European, were tested further with these probes. With probe 12R1C1, only two of several Hhal fragment patterns were seen among haploid drone progeny of each queen bee, indicating that the patterns represented alleles at a single locus. Four alleles detected by probe 12R1C1 were described previously, three of which had been found only in populations of African descent. In this study, one of the three was found at a low frequency among samples from western Europe, northern Mexico, and the United States. However, ten additional alleles were discovered in South African drones, six of which were seen also in neotropical African colonies. With probe 2A2, only one or the other of two Alul restriction fragments was detected in drones indicating that the fragments represented alles at a single locus. One of the two alleles, seen previously only in populations of African descent, was found at a very low frequency in bees from western Europe and northern Mexico.     

Host preference of the honey bee tracheal mite (Acarapis woodi (Rennie))

Field and laboratory bioassays were used to test the preference of the honey bee tracheal mite,Acarapis woodi (Rennie), for drones versus workers. Groups of newly-emerged drones and workers were marked and introduced into either heavily infested colonies (field bioassays) or into the cages of infested bees obtained from the field colonies (laboratory bioassays). Seven days later all of the marked bees in each bioassay were removed. The numbers of mites of each life stage in each drone or worker target bee of each experiment were quantified. Mite prevalence values for the two castes were not found to differ significantly for either experiment. However, the caste of the target bee was shown to influence the migration of the adult female mites. Drones contained a greater number of migratory female mites and greater total numbers of all mite stages as compared to workers. These results indicate that migrating female mites preferentially infest drones and suggest that the role of drones in the dissemination and population dynamics of the tracheal mite needs to be examined further.     

Genetic Analysis of the Drifting of Drones in Apis mellifera Using Multilocus DNA Fingerprinting

The presence of non-native drones in colonies of Apis mellifera was studied using multilocus DNA fingerprinting. Drones revealing a fingerprinting DNA banding pattern that did not correspond to the queen's genotype were classified as non-native animals. As previously reported for the drifting of workers, the position of the hive in relation to neighbouring colonies and the orientation of the flight entrance towards the sun showed significant correlations to the number of drifted drones in a colony. The frequency of non-native drones was low in central colonies (13 %) but high in marginal colonies (24 %). Furthermore, there was a significant correlation (r = 0.56) between the band-sharing coefficient of the non-native drones and the queen, and the number of drifted drones in the colony, which might indicate that genetically based nestmate recognition is involved in the drifting and/or acceptance of foreign drones in the colony.     

利用VNTR分子标记鉴定蜜蜂群内蜂王交配次数和雄蜂母系来源

如何准确测定蜂王交配次数和雄蜂母系来源,是研究蜜蜂亚家系行为生物学的关键。本研究利用王浆主蛋白（MRJPs）的串联重复序列多态性（VNTR）分子标记分别鉴定了蜂王单雄人工授精、双雄人工授精和自然交尾的中华蜜蜂Apis cerana cerana蜂群中的蜂王交配次数和雄蜂母系来源。结果表明： 在蜂王单雄人工授精和双雄人工授精蜂群中,蜂王的交配次数分别为1和2;在蜂王自然交尾的2个蜂群中,蜂王的交配次数分别为8和5。另外,经鉴定发现：在以上实验蜂群中,所有雄蜂都是由蜂王产的未受精卵发育而来。因此,作为一种分子标记,蜜蜂MRJPs VNTR能简单、有效地鉴定蜂群内蜂王的交配次数和雄蜂母系来源。     

Some reproductive characteristics of honeybee drones in relation to their ages

The number of spermatozoa, length of testis, length of mucus gland and weights of drones were estimated in caged and free honeybee drones in relation to their ages. For this purpose, three Carniolan colonies were used as sources of drones and two were used as nursery colonies. The drones were held either in cages or freely in the queenless part of the nursery colonies. Measurements were carried out on samples of drones taken at 3-day intervals from 1–3, 4–6, 7–9, 10–12 and 13–15 days old. While the number of spermatozoa in drone testes decreased in both caged and free drones as the drone age increased, it increased gradually in the seminal vesicles. The results also showed that weight of drones and length of testes decreased, but the length of the mucus gland did not significantly differ with age. Further, the drones' weight, length of mucus gland and total number of spermatozoa tend to be slightly larger in the caged than in free drones. The total number of spermatozoa in all parts of the reproductive organs was lower in the older than younger drones; thus, the number of spermatozoa in the newly emerged drones does not help to predict the real number reaching the queen during mating.     

Is the membrane voltage amplifier of drone photoreceptors useful at physiological light intensities?

Free-flying drones (Apis mellifera) were attracted by pheromone to an elevated observation site where they looked for small distant objects, a visual task similar to nuptial pursuit. The brightness of the sky against which drones performed this task was measured as the radiance over a range of wavelengths covering the absorbance spectra of the principal drone rhodopsin and its metarhodopsin. This brightness varied relatively little, by just over one log unit. In laboratory experiments on the intact drone, the amplitude of photoreceptor responses to small decrements in intensity showed a marked maximum when the background intensity depolarized the cells to about –35mV. The radiance of this optimal background was only 0.2 log units greater than the sky radiance at which most drones were seen. It is argued that because of probable systematic errors the true difference may be less. It is known that in superfused retinal slices voltage-dependent sodium channels amplify small signals under these stimulus conditions. We therefore conclude that this amplification is useful for the major visual activity of the drone.     

意大利蜜蜂刚出房与性成熟雄蜂的蛋白质组差异分析

【目的】对意大利蜜蜂Apis mellifera ligustica刚出房雄蜂与性成熟雄蜂的蛋白质组进行比较,探讨雄蜂在性成熟过程中蛋白质表达变化,为进一步研究雄蜂发育生物学获得差异表达蛋白质方面的依据。【方法】采用双向电泳法建立意大利蜜蜂雄蜂发育过程中刚出房时与性成熟期的蛋白质表达谱,通过质谱分析与数据库检索,鉴定部分差异蛋白。【结果】在意大利蜜蜂刚出房雄蜂和性成熟雄蜂中分别检测到2 490和2 317个蛋白点,其中差异表达蛋白点有157个。在刚出房雄蜂中高度表达的蛋白点有102个;在性成熟雄蜂中高度表达的蛋白点有55个。对部分差异蛋白进行质谱分析,共鉴定了18个蛋白点,其中在刚出房雄蜂中上调表达的蛋白有肌钙蛋白、SEC13蛋白、DJ蛋白等,在性成熟雄蜂中上调表达的蛋白有副肌球蛋白、精氨酸激酶、肌动蛋白解聚因子等。【结论】意大利蜜蜂雄蜂在性成熟发育过程中,其体内大量蛋白表达发生了变化,其差异表达的蛋白质可能与骨骼、飞行肌以及精子发育等机能有关。     

Characterization of HSP70 expression in drones of Apis cerana (Hymenoptera: Apidae)

Heat shock proteins (HSPs) constitute a superfamily of molecular chaperones that are rapidly biosynthesized in response to various biotic and abiotic factors. In this study, we first cloned the full-length HSP70 gene of the Eastern honeybee Apis cerana. Then, using real-time quantitative PCR, we explored HSP70 expression profiles in drones at different developmental stages, ages, and reproductive statuses (with and without semen). The full-length HSP70 cDNA is 2421 bp, including a 1953-bp open reading frame (ORF) that encodes a polypeptide of 650 amino acids. The HSP70 gene consists of one intron and two exons. The phylogenetic analysis revealed that the HSP70 genes of A. cerana and Apis mellifera are the most closely related. We observed HSP70 expression at all selected developmental stages and detected the highest expression in pupae with an unpigmented body cuticle and brown eyes (Pb) and much lower expression in larvae hatched within 72 h. In adult drones of different ages, the highest expression level of HSP70 was observed in 16-day-old drones; significantly lower accumulation of HSP70 mRNA was detected in 4-day-old drones. There was no significant difference in HSP70 expression between drones with and without semen captured at the entrance, while the HSP70 gene expression level strikingly differed between drones captured at the entrance and the drones collected within the hive. Our study suggests that HSP70 might play a critical role in drone development and during reproductive mating events.     

蜂王上颚腺信息素对雄蜂候选性信息素受体基因表达的影响

【目的】性信息素受体(sex pheromone receptors, PRs)是雄蜂感受蜂王上颚腺信息素(queen mandibular pheromone, QMP)的重要受体。本研究分析中华蜜蜂Apis cerana cerana(简称"中蜂")和意大利蜜蜂Apis mellifera ligustica(简称"意蜂")雄蜂触角和大脑中候选性信息素受体基因Prs受QMP刺激下的表达特征,为探索蜜蜂气味受体(OR)基因的功能研究提供理论依据。【方法】利用qRT-PCR技术检测分析分别用10μL QMP[7.04μg/μL反式-9-氧代-2-癸烯酸(9-ODA)+1.26μg/μL 9-羟基-2-癸烯酸(9-HDA)+0.03μg/μL对羟基苯甲酸甲酯(HOB)]和10μL 7.04μg/μL 9-ODA处理对飞行状态和爬行状态下的中蜂雄蜂和意蜂雄蜂触角和大脑中4个气味受体基因(Or10,Or11,Or18和Or170)的mRNA表达量的影响。【结果】与空白对照组相比,QMP及9-ODA均能显著下调中蜂雄蜂和意蜂雄蜂触角与大脑中Or11的mRNA表达量;中蜂雄蜂触角中AcOr18和...     

Multiple excitatory receptor types on individual olfactory neurons: implications for coding of mixtures in the spiny lobster

The aim of our paper was to investigate whether single olfactory receptor neurons (ORNs) of the spiny lobster Panulirus argus functionally express more than one type of receptor, examine the consequences of this on coding of mixtures, and compare principles of odorant mixture coding by spiny lobsters with that by the channel catfish, which has been studied extensively using the same experimental and analytical procedures (Caprio et al. 1989; Kang and Caprio 1991). We examined responses of individual taurine-sensitive ORNs to binary mixtures of excitatory compounds, either competitive agonists (taurine, β-alanine, hypotaurine) or non-competitive agonists (taurine, l-glutamate, ammonium chloride, adenosine-5′-monophosphate). Responses to mixtures were compared to two indices: mixture discrimination index (MDI) and independent component index (ICI). Binary mixtures of competitive agonists had MDI values close to 1.0, as expected for competitors. Mixtures of non-competitive agonists had ICI values averaging 0.83, indicating the effects of the components are not independent. We conclude that individual olfactory cells of spiny lobsters can express more than one type of receptor mediating excitation, one of which typically has a much higher density or affinity, and that spiny lobster and catfish olfactory cells encode mixtures of two excitatory agonists using similar rules. Accepted: 20 December 1996