Factors determining the release of Nasonov pheromone by honeybees at the hive entrance

ABSTRACT. Worker bees recently denied access to their colony expose their Nasonov glands, thereby releasing pheromone, at the entrance to their hive. Odours of the following induced this response: empty comb, purified beeswax, honey, pollen, propolis, a live queen, the (E)-9-hydroxy-2-decenoic acid component of a queen's mandibular glands, live drones and workers, inert material on which workers had walked inside the hive, and synthetic Nasonov pheromone. The total odour of a foreign colony also induced worker bees to expose their Nasonov glands but was less effective than the odour of their own colony. Odours of the following were not effective: the (E)-9-oxo-2-decenoic acid component of a queen's mandibular glands, recently killed drones and workers, worker brood (eggs, larvae, pupae).     

蜜蜂蜂王信息素研究进展

综述了蜂王信息素的化学组成、特性、作用 ,以及与幼虫信息相互关系的研究进展 ,对蜂王信息素在养蜂和植物授粉中的应用做了介绍。西方蜜蜂的蜂王上颚腺信息素 (queen’smandibularglandpheromone,QMP)。QMP包含了 5种成分 :(E) -9-氧 -2 -癸烯酸 ( 9 ODA)、(R ,E) ( ) 和 (S,E) ( +) 9 羟基 -2 -癸烯酸 ( -9 HDA和 +9 HDA)、甲基p -羟基安息香酸盐 (HOB)、4-羟基 -3 -甲氧苯乙醇 (也称香草醇 ,HVA) ,9 ODA是其中最重要的成分 ;QMP的组分与蜜蜂的进化程度有关 ,进化程度越高则组分越复杂 ;QMP通过抑制保幼激素的产生来调节青年工蜂的个体发育。     

Techniques for studying honeybee pheromones involved in clustering, and experiments on the effect of Nasonov and queen pheromones

ABSTRACT. Techniques for investigating pheromones responsible for clustering in Apis mellifera are described. Stable queenless clusters were formed in response to synthetic Nasonov pheromone mixed with (E)-9-oxo-2-decenoic acid. This mixture plus the addition of (E)-9-hydroxy-2-decenoic acid was less potent in initiating cluster formation than it was without this addition, but the clusters once formed sometimes grew larger. Other unknown components from the queen's mandibular glands encouraged cluster formation.     

Mandibular Gland Volatiles and Their Ontogenetic Patterns in Queen Honey Bees,Apis mellifera carnica

Extracts of mandibular glands taken from adult queens of the honey bee, Apis mellifera carnica, were analysed by gas chromatography-mass spectroscopy. More than 100 compounds could be identified among which oxygenated fatty acids with six, eight, 10 and 12 carbon atoms are particularly interesting since they show structural relationships to the queen substance, (E)-9-oxo-2-decenoic acid. Changes in the patterns of volatiles were followed up from emergence until the full dominant status of an egg-laying queen in a strong colony. Generally, the amount of volatiles per gland was found to increase with age. The final level of queen substance (9-ODA) content is reached at the postmating stage about 10 days after emergence. Ontogenetic patterns of concentrations were determined for those components regarded to predominantly contribute to the royal pheromone. Characteristic compositions of signals, possibly involved in the premating, mating and postmating dominance status of a honey bee queen are discussed. Copyright 1997 Elsevier Science Ltd. All rights reserved     

Primer effect of queen pheromone on juvenile hormone biosynthesis in adult worker honey bees

Juvenile hormone synthesis in adult worker honey bees was measured by an in vitro corpora allata bioassay. Adult queenless workers exhibit higher rates of juvenile hormone biosynthesis than queenright workers. Hormone synthesis is not correlated with the volume of the glands. Extract of queen mandibular glands, applied to a dummy, reduces juvenile hormone biosynthesis in caged queenless workers to the level of queenright workers. The same result was obtained with synthetic (E)-9-oxo-2-decenoic acid, the principal component of the queen mandibular gland secretion. This pheromonal primer effect may function as a key regulating element in maintaining eusocial colony homeostasis. The presence of brood does not affect the hormone production of the corpora allata.Abbreviations BSA bovine serum albumin - CA Corpora allata - JH juvenile hormone - 9-ODA (E)-9-oxo-2-decnoic acid     

Structural basis of the honey bee PBP pheromone and pH-induced conformational change

The behavior of insects and their perception of their surroundings are driven, in a large part, by odorants and pheromones. This is especially true for social insects, such as the honey bee, where the queen controls the development and the caste status of the other individuals. Pheromone perception is a complex phenomenon relying on a cascade of recognition events, initiated in antennae by pheromone recognition by a pheromone-binding protein and finishing with signal transduction at the axon membrane level. With to the objective of deciphering this initial step, we have determined the structures of the bee antennal pheromone-binding protein (ASP1) in the apo form and in complex with the main component of the queen mandibular pheromonal mixture, 9-keto-2(E)-decenoic acid (9-ODA) and with nonpheromonal components. In the apo protein, the C terminus obstructs the binding site. In contrast, ASP1 complexes have different open conformations, depending on the ligand shape, leading to different volumes of the binding cavity. The binding site integrity depends on the C terminus (111-119) conformation, which involves the interplay of two factors; i.e. the presence of a ligand and a low pH. Ligand binding to ASP1 is favored by low pH, opposite to what is observed with other pheromone-binding proteins, such as those of Bombyx mori and Anopheles gambiae.     

Movement of honey bee (Apis mellifera L.) queen mandibular gland pheromone in populous and unpopulous colonies

The mode of intranest transfer of the honey bee queen mandibular gland pheromone complex (QMP) was investigated in unpopulous and populous, slightly congested colonies, using synthetic QMP containing tritiated 9-keto-2(E)-decenoic acid, one of the QMP components. Radiolabel was rapidly transported from the center to the peripheral regions of the nest, and in a manner consistent with worker to worker transport. Population size and congestion had no effect on the relative rates of movement from the center to the periphery of the nest or on the mean amounts of radiolabel on individual bees. However, a significantly smaller proportion of the workers in the populous colonies received detectable amounts of radiolabel than in the uncongested colonies, and workers carrying especially large amounts of radiolabel were less numerous in the crowded colonies. It is suggested that, at the stage of colony development that the colonies were in, population size has more of an effect on intranest pheromone transmission than does crowding. Interference with pheromone transfer may occur only at higher levels of congestion than were created, and nearer to the reproductive phase of colony development. An alternative hypothesis is that colony crowding does not significantly affect QMP transport and that the onset of reproductive queen rearing may be associated more with changes in worker thresholds of response to QMP.     

Wild genius - domestic fool? Spatial learning abilities of wild and domestic guinea pigs

Background

In social insects, the queen is essential to the functioning and homeostasis of the colony. This influence has been demonstrated to be mediated through pheromone communication. However, the only social insect for which any queen pheromone has been identified is the honey bee (Apis mellifera) with its well-known queen mandibular pheromone (QMP). Although pleiotropic effects on colony regulation are accredited to the QMP, this pheromone does not trigger the full behavioral and physiological response observed in the presence of the queen, suggesting the presence of additional compounds. We tested the hypothesis of a pheromone redundancy in honey bee queens by comparing the influence of queens with and without mandibular glands on worker behavior and physiology.

Results

Demandibulated queens had no detectable (E)-9-oxodec-2-enoic acid (9-ODA), the major compound in QMP, yet they controlled worker behavior (cell construction and queen retinue) and physiology (ovary inhibition) as efficiently as intact queens.

Conclusions

We demonstrated that the queen uses other pheromones as powerful as QMP to control the colony. It follows that queens appear to have multiple active compounds with similar functions in the colony (pheromone redundancy). Our findings support two hypotheses in the biology of social insects: (1) that multiple semiochemicals with synonymous meaning exist in the honey bee, (2) that this extensive semiochemical vocabulary exists because it confers an evolutionary advantage to the colony.     

Age dependency of worker bee response to queen pheromone in a four-armed olfactometer

Summary Behavioral responses of differently aged worker beesApis mellifera to a queen pheromonal extract were analysed. The bees were tested individually in a four-armed olfactometer, one arm being scented with the pheromonal extract. This extract was prepared from heads of 14–17-day-old unmated queens. Among the components of the blend, 470 g 9-keto-2-(E)-decenoic acid, 200 g 9-hydroxy-2-(E)-decenoic acid and 5 gp-hydroxybenzoic acid methyl ester per queen equivalent were dosed. An age dependency in the worker bees' olfactory response to the components of the queen extract was shown, the strongest response occurring below the age of 5 days.     

Suppression of queen rearing in European and Africanized honey beesApis mellifera L. by synthetic queen mandibular gland pheromone

Summary Queen rearing is suppressed in honey bees (Apis mellifera L.) by pheromones, particularly the queen's mandibular gland pheromone. In this study we compared this pheromonally-based inhibition between temperate and tropically-evolved honey bees. Colonies of European and Africanized bees were exposed to synthetic queen mandibular gland pheromone (QMP) for ten days following removal of resident queens, and their queen rearing responses were examined. Queen rearing was suppressed similarly in both European and Africanized honey bees with the addition of synthetic QMP, indicating that QMP acts on workers of both races in a comparable fashion. QMP completely suppressed queen cell production for two days, but by day six, cells containing queen larvae were present in all treated colonies, indicating that other signals play a role in the suppression of queen rearing. In queenless control colonies not treated with QMP, Africanized bees reared 30% fewer queens than Europeans, possibly due to racial differences in response to feedback from developing queens and/or their cells. Queen development rate was faster in Africanized colonies, or they selected older larvae to initiate cells, as only 1 % of queen cells were unsealed after 10 days compared with 12% unsealed cells in European colonies.     

Chemical communication in Ropalidia marginata: Dufour's gland contains queen signal that is perceived across colonies and does not contain colony signal

Queens of the primitively eusocial wasp Ropalidia marginata appear to maintain reproductive monopoly through pheromone rather than through physical aggression. Upon queen removal, one of the workers (potential queen, PQ) becomes extremely aggressive but drops her aggression immediately upon returning the queen. If the queen is not returned, the PQ gradually drops her aggression and becomes the next queen of the colony. In a previous study, the Dufour's gland was found to be at least one source of the queen pheromone. Queen-worker classification could be done with 100% accuracy in a discriminant analysis, using the compositions of their respective Dufour's glands. In a bioassay, the PQ dropped her aggression in response to the queen's Dufour's gland macerate, suggesting that the queen's Dufour's gland contents mimicked the queen herself. In the present study, we found that the PQ also dropped her aggression in response to the macerate of a foreign queen's Dufour's gland. This suggests that the queen signal is perceived across colonies. This also suggests that the Dufour's gland in R. marginata does not contain information about nestmateship, because queens are attacked when introduced into foreign colonies, and hence PQ is not expected to reduce her aggression in response to a foreign queen's signal. The latter conclusion is especially significant because the Dufour's gland chemicals are adequate to classify individuals correctly not only on the basis of fertility status (queen versus worker) but also according to their colony membership, using discriminant analysis. This leads to the additional conclusion (and precaution) that the ability to statistically discriminate organisms using their chemical profiles does not necessarily imply that the organisms themselves can make such discrimination.     

The ontogenetic pattern of mandibular gland components in queenless worker bees (Apis mellifera capensis Esch.)

The quantity and composition of the six major mandibular gland components of young queenless workers of the Cape honeybee (Apis mellifera capensis) were determined. The total amount of the six components increased with age. The relative quantities in the mandibular gland secretion of queenless caged workers were found to change rapidly during the first 4 days after emergence and to become dominated by the queen substance, 9-keto-2(E)-decenoic acid. Also the relative amounts of 9-hydroxy-decenoic acid, a precursor of the queen substance, showed an increase of an order of magnitude within the first 4 days of imaginal life. The relative amounts of the aromatic compounds typical to the queen pheromone remained similar in this developmental time window. The increase of queenlike compounds is particularly strong between days two and three after emergence. These queen-like pheromones play a major role in the development of reproductive hierarchies among workers under queenless conditions. This may be an important factor in the socio-parasitic pathway of A. m. capensis.     

Transfer of pheromone from immature queen honeybees, Apis mellifera

ABSTRACT. Immediately after visiting cells containing immature queens, workers of Apis mellifera L. were observed to engage in prolonged cleaning, particularly of their tongues when they had visited larvae, and of their antennae when they had visited pupae. Thereafter other workers usually initiated and made antennal contacts with them. During such antennal contact the bee that had visited the queen larva often donated food. The implication of these findings on the distribution of pheromone produced by immature queens is discussed. Workers were stimulated to make antennal contact with the excised heads of bees from a queen's court, providing further evidence that queen pheromone is transferred between workers' antennae.     

Queen Bee Pheromone Binding Protein pH-Induced Domain Swapping Favors Pheromone Release

In honeybee (Apis mellifera) societies, the queen controls the development and the caste status of the members of the hive. Queen bees secrete pheromonal blends comprising 10 or more major and minor components, mainly hydrophobic. The major component, 9-keto-2(E)-decenoic acid (9-ODA), acts on the workers and male bees (drones), eliciting social or sexual responses. 9-ODA is captured in the antennal lymph and transported to the pheromone receptor(s) in the sensory neuron membranes by pheromone binding proteins (PBPs). A key issue is to understand how the pheromone, once tightly bound to its PBP, is released to activate the receptor. We report here on the structure at physiological pH of the main antennal PBP, ASP1, identified in workers and male honeybees, in its apo or complexed form, particularly with the main component of the queen mandibular pheromonal mixture (9-ODA). Contrary to the ASP1 structure at low pH, the ASP1 structure at pH 7.0 is a domain-swapped dimer with one or two ligands per monomer. This dimerization is disrupted by a unique residue mutation since Asp35 Asn and Asp35 Ala mutants remain monomeric at pH 7.0, as does native ASP1 at pH 4.0. Asp35 is conserved in only ∼ 30% of medium-chain PBPs and is replaced by other residues, such as Asn, Ala and Ser, among others, thus excluding that they may perform domain swapping. Therefore, these different medium-chain PBPs, as well as PBPs from moths, very likely exhibit different mechanisms of ligand release or receptor recognition.     

Quantum chemical study on the stability of honeybee queen pheromone against atmospheric factors

The managed honeybee, Apis mellifera, has been experienced a puzzling event, termed as colony collapse disorder (CCD), in which worker bees abruptly disappear from their hives. Potential factors include parasites, pesticides, malnutrition, and environmental stresses. However, so far, no definitive relationship has been established between specific causal factors and CCD events. Here we theoretically test whether atmospheric environment could disturb the chemical communication between the queen and their workers in a colony. A quantum chemistry method has been used to investigate for the stability of the component of A. mellifera queen mandibular pheromone (QMP), (E)-9-keto-2-decenoic acid (9-ODA), against atmospheric water and free radicals. The results show that 9-ODA is less likely to react with water due to the high barrier heights (~36.5 kcal?·?mol^?1) and very low reaction rates. However, it can easily react with triplet oxygen and hydroxyl radicals because of low or negative energy barriers. Thus, the atmospheric free radicals may disturb the chemical communication between the queen and their daughters in a colony. Our pilot study provides new insight for the cause of CCD, which has been reported throughout the world.     

Variation in worker response to honey bee (Apis mellifera L.) queen mandibular pheromone (Hymenoptera: Apidae)

Genetic and environmental influences on the worker honey bee retinue response to queen mandibular gland pheromone (QMP) were investigated. Worker progeny were reared from queens originating from four sources: Australia, New Zealand, and two locations in British Columbia, Canada (Simon Fraser University and Vancouver Island). Progeny from New Zealand queens responded significantly higher (P < 0.05) than progeny from Australia in a QMP retinue bioassay. Retinue response was not related to queen production of pheromone or colony environment, and the strain-dependent differences in retinue bioassay responses were maintained over a wide range of dosages. Selected high- and low-responding colonies were bioassayed over the course of 1 year. High-responding colonies contacted QMP lures more frequently than low-responding colonies (P < 0.05) throughout the year except in late summer. We conclude that there is a strong genetic component to QMP response by worker honey bees, as well as a seasonal effect on response.     

The role of queen mandibular pheromone and colony congestion in honey bee (Apis mellifera L.) reproductive swarming (Hymenoptera: Apidae)

The roles of honey bee queen mandibular pheromone and colony congestion in the inhibition of swarming were investigated. Two colony siz.es were used: small, congested colonies and large, uncongested colonies. Both groups of colonies were treated with various dosages of the five-component, synthetic queen mandibular pheromone in the spring, and the extent and timing of swarming were followed. Most treatment groups received pheromone or a solvent blank (control) on a stationary slide; one group of the congested colonies received a pheromone treatment via an aerosol spray. The pheromone was not effective at delaying swarming in the congested colonies at any dosage applied on slides, but the aerosol spray-treated colonies swarmed significantly later in the season than the control colonies. The uncongested, pheromone-treated colonies exhibited a dose-dependent delay in swarming, with the highest dosage colonies swarming almost four weeks later than the control colonies. These results indicate an interaction between congestion and pheromone in the control of honey bee reproduction. While congestion may in itself be a factor stimulating swarming, these results are consistent with the interpretation that colony congestion reduces the transmission of queen pheromone within the nest, thereby removing the queen 's pheromone-based inhibition of queen rearing and subsequent swarming by workers.     

Queens, not workers, produce the males in the stingless bee Schwarziana quadripunctata quadripunctata

Most stingless bee colonies have one singly mated queen, resulting in a potential conflict between workers and queen over male production, because workers are more closely related to the sons of other workers than they are to the queen's sons. Furthermore, workers in the majority of stingless bee species have ovarian development, can produce haploid eggs, and show apparently agonistic behaviour towards their queen, suggesting a real conflict. We investigated whether genetic conflict over male production resulted in reproductive and behavioural conflict in Schwarziana q. quadripunctata. DNA microsatellite loci showed that, even though workers are more related to other workers' sons than to queen's sons, it is the queen who produces the males. Behavioural interactions between workers and their queen were not uniformly more aggressive during male production than at times with only worker production, although some differences might have been obscured by the fact that food supply was greater during male production. The potential conflict over male production inS. q. quadripunctata seems not to lead to an observable conflict between the workers and their queen. Workers might refrain from reproduction because of the costs involved for the colony or because of queen control.     

Queen substances from the abdomen of the honey bee queen

Summary The secretion of the mandibular glands of a honey bee queen enables the worker bees to react to the presence of their queen. Extirpating the mandibular glands of the queen does not prevent that she is accepted by her colony. Hitherto this was attributed to contamination of the queen's body by mandibular gland substances during or preceding the extirpation. When, however, these glands are extirpated before they have secreted any material and the queens are inseminated artificially, the colonies still accept these queens. A normal-sized retinue, the absence of emergency cell building and the absence of activation of the worker's ovaries indicate that such a queen is still able to maintain her social position. This supports Verheijen-Voogd's (1959) conclusion that the queen's influence on her workers has a behavioural basis (chemoreception) rather than a biochemical one.Laboratory experiments reveal that apart from the mandibular gland substances other queen pheromones are produced in glands on the abdomen, most probably in the glands described by Renner and Baumann (1964).     

Queen pheromone transfer within honeybee colonies

ABSTRACT. The observations provided strong circumstantial evidence that workers in a queen's court obtain queen pheromone on their antennae, and that queen pheromone is distributed through the colony during antennal contact between workers. Workers that had just left the court of a mated or virgin queen had an increased tendency to make reciprocated antennal contacts with other workers. This tendency was reinforced when the workers concerned licked the queen in addition to palpating her with their antennae, probably because they spent longer in the court. The first workers contacted by those leaving the court also had an increased tendency to make reciprocated antennal contacts. Antennal contacts were more likely to be initiated by bees other than those from the queen's court. Workers from the court and those they first contacted, participated in food transfer more than did workers selected at random. Workers that licked a virgin queen subsequently participated in food transfer more than those that palpated her with their antennae only. Within about 5 min of leaving the court, a worker's participation in reciprocated antennal contacts and in food transfer diminished to the level of non-court workers. Workers chosen at random made more transient and non-reciprocated antennal contacts when in a colony with a mated queen than when in a colony with a virgin queen.