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PubMed2003

Discrimination of single bars by the honeybee (Apis mellifera).

The bees learn to come for a reward to a very simple pattern, a black bar in a fixed position on a white background, in a Y-choice apparatus, with the targets presented in the vertical plane at a fixed range. They were trained on a number of different arrangements of a single bar on one or both targets. The trained bees were then given appropriate tests to discover what cues they had learned. A cue is an essential parameter that is recognized, not the whole pattern. At the choice point they learn exactly which way to look for consistent cues. After training on a single broad bar versus a blank target, they respond in tests to any area of black where they expect to see it, and are less able to detect it the more it has been displaced from the training position. They are more sensitive to vertical than to horizontal displacement of the bar. The cue is anything black of the right size. They do not recognize the shape or orientation of the bar. When trained to discriminate between two bars at right angles to each other, centred on the reward hole, the cue is the edge orientation at the expected places on the targets, and the bees are less able to discriminate the orientation cues the more they are displaced. When trained on a pair of broad black bars in different positions, the cues are the vertical positions of the centres. Division of the bar into squares, or making the edges stepped, removes the orientation cue but not the position cue. Addition of a large black spot or a checkerboard background to the original bar prevents discrimination, as if the spatial reference frame is disturbed. In training, or testing trained bees, parallax does not assist the discrimination of orientation.

Animals↗
PubMed2006

8. The development and evolution of division of labor and foraging specialization in a social insect (Apis mellifera L.).

How does complex social behavior evolve? What are the developmental building blocks of division of labor and specialization, the hallmarks of insect societies? Studies have revealed the developmental origins in the evolution of division of labor and specialization in foraging worker honeybees, the hallmarks of complex insect societies. Selective breeding for a single social trait, the amount of surplus pollen stored in the nest (pollen hoarding) revealed a phenotypic architecture of correlated traits at multiple levels of biological organization in facultatively sterile female worker honeybees. Verification of this phenotypic architecture in "wild-type" bees provided strong support for a "pollen foraging syndrome" that involves increased senso-motor responses, motor activity, associative learning, reproductive status, and rates of behavioral development, as well as foraging behavior. This set of traits guided further research into reproductive regulatory systems that were co-opted by natural selection during the evolution of social behavior. Division of labor, characterized by changes in the tasks performed by bees, as they age, is controlled by hormones linked to ovary development. Foraging specialization on nectar and pollen results also from different reproductive states of bees where nectar foragers engage in pre-reproductive behavior, foraging for nectar for self-maintenance, while pollen foragers perform foraging tasks associated with reproduction and maternal care, collecting protein.

Animals↗
PubMed1992

Biochemical variability of venoms from individual European and Africanized honeybees (Apis mellifera).

To study biochemical differences between venom from individual honeybees, venom sacs from 103 European (EU) bees and 92 Africanized bees representing 12 different colonies were dissected, and the dry weight (DW) of venom from each bee was determined. Venom from each of these bees was studied with isoelectric focusing and functional assays for phospholipase A2 and melittin. Phospholipase concentrations in individual EU bee venoms varied between 1.8% and 27.4% (wt/wt). The melittin concentration in EU bee venom varied less and, on the average, was found to be much lower than previously reported. There was an eightfold to ninefold difference between lowest and highest venom sac DW contents, suggesting the possibility of highly variable venom delivery from bee stings. One EU bee contained greater than 300 micrograms of venom, three times the recommended maintenance dose for venom immunotherapy. Isoelectric focusing also demonstrated large differences between individual bees, with respect to major and minor components of their venoms. Africanized bees contained significantly less venom but more phospholipase than did EU bees. Bee venoms from different colonies differed in their DW content and in their concentrations of phospholipase and melittin. The results are relevant to the uncertainty of responses from sting challenges and field stings in allergic patients and massive stinging attacks on normal subjects.

Africa↗
PubMed2000

Pharmacological interference with glutamate re-uptake impairs long-term memory in the honeybee, apis mellifera.

The role of glutamate in the central nervous system of invertebrates is poorly understood. In the present study we examined the effects of a glutamate transporter inhibitor, L-trans-2,4-pyrrolidine dicarboxylate (L-trans-2,4-PDC), on memory formation in the honeybee following a three-trial classical conditioning of the proboscis extension reflex (PER). Pre-training injections of the drug have no effect on acquisition and short-term (1 h) memory, but impair long-term (24 h), associative olfactory memory in a dose-dependent manner. This effect is transient and the amnesiac individuals can be re-trained successfully 48 h after injections. Our results suggest that glutamatergic neurons in the honeybee brain, in particular those found in the mushroom bodies (MBs), may be part of the circuitry involved in processing of long-term olfactory memory. Such a role for this neurotransmitter is consistent with our previous results showing that glutamate and glutamate transporter(s) are localised in regions of the honeybee brain implicated in higher order processing.

Amnesia↗
PubMed1998

Behavioural pharmacology of dopamine, serotonin and putative aminergic ligands in the mushroom bodies of the honeybee (Apis mellifera).

The proboscis extension response (PER) which can be elicited in bees by stimulating one antenna with water vapour, was used to quantify the effects of dopamine, serotonin (5-HT) and putative receptor ligands in the mushroom body of the bee. The drugs were microinjected into the alpha-lobe of the mushroom body in one brain hemisphere. Injection of dopamine reduces the water vapour-elicited PER significantly. The effects of dopamine are limited to the treated side. Injection of 5-HT has similar effects to dopamine. The effects of 5-HT are apparent on the treated and partly also on the contralateral side. Significant effects for dopamine on the treated side were found when the concentration in the injected drop was 10(-7) M. For 5-HT significant effects on the treated side were apparent for concentrations of 10(-8) M. Putative dopamine and 5-HT receptor ligands were injected alone and coinjected with the amines. Two ligands with dopamine-antagonistic effects were found: buspirone > spiperone, while lisuride, sulpiride, chlorpromazine, SCH 23390, butaclamol and haloperidol had no dopamine-antagonistic effects. All tested putative 5-HT receptor ligands had significant 5-HT-antagonistic effects: butaclamol > methysergide > lisuride > cyproheptadine > SCH 23390. Good correlations between the behavioural data and in vitro radioligand binding studies were found for 5-HT receptor ligands, while there exist only partial correlations for dopamine receptor ligands.

Animals↗
PubMed2002

Molecular profiling of behavioural development: differential expression of mRNAs for inositol 1,4,5-trisphosphate 3-kinase isoforms in naive and experienced honeybees (Apis mellifera).

In seeking genetic factors that may control the extended behavioural maturation of adult honeybees we found that inositol 1,4,5-trisphosphate (IP(3)) 3-kinase, a key enzyme in the IP(3)-mediated signalling cascade, is differentially expressed in brains of naive, newly emerged bees and experienced foragers. DNA sequencing yielded a contig of 21.5 kb spanning the honeybee IP(3)K locus and a 3' flanking gene similar to a transcription factor NFR-kappa-B. The IP(3)K locus gives rise to three differentially expressed major transcripts produced by alternative splicing that encode proteins with identical, highly conserved C-termini and distinct, non-conserved N-terminal domains. The type A transcript is dominant in the adult brain and its level of expression increases threefold during the first 4 days of adult development. The type B message is expressed in brains of naive bees, but is also found in the thorax and abdomen, whereas transcript C is expressed largely in non-neural tissues and in the antenna. In contrast to type A message, the brain levels of transcript B decrease during the first 4 days of adult life. Our data are evaluated in the context of the contrasting behavioural phenotypes of immature and experienced worker honeybees.

Animals↗
PubMed2003

Analysis of two D1-like dopamine receptors from the honey bee Apis mellifera reveals agonist-independent activity.

Dopamine is found in many invertebrate organisms, including insects, however, the mechanisms through which this amine operates remain unclear. We have expressed two dopamine receptors cloned from honey bee (AmDOP1 and AmDOP2) in insect cells (Spodoptera frugiperda), and compared their pharmacology directly using production of cAMP as a functional assay. In each assay, AmDOP1 receptors required lower concentrations of dopamine and 6,7-ADTN for maximal activation than AmDOP2 receptors. Conversely, butaclamol and cis(Z)-flupentixol were more potent at blocking the cAMP response mediated through AmDOP2 than AmDOP1 receptors. Expression of AmDOP1, but not AmDOP2, receptors significantly increased levels of cAMP even in the absence of ligand. This constitutive activity was blocked by cis(Z)-flupentixol. This work provides the first evidence of a constitutively activated dopamine receptor in invertebrates and suggests that although AmDOP1 and AmDOP2 share much less homology than their vertebrate counterparts, they display a number of functional parallels with the mammalian D1-like dopamine receptors.

Animals↗
PubMed2003

Efficacy of formic acid in gel for Varroa control in Apis mellifera L.: importance of the dispenser position inside the hive.

The efficacy of formic acid in a gel matrix was evaluated in two groups of honeybee colonies. In Group 1, a dispenser with 120 g of formic acid (70%) in gel was placed on the brood combs and another dispenser with the same dose was located on the hive bottom (total dose, 240 g). Group 2 received two doses of 240 g of formic acid (70%) in gel and each application was applied in two dispensers containing 120 g of the formic acid solution each and they were located over the brood chamber (total dose, 480 g). In Group 2, the period between both applications was 15 days, and the efficacies after the first and both applications were calculated. Significant differences were registered for final efficacy between both groups. When final efficacy of Group 1 was compared with efficacy after first application of Group 2, significant differences were found (P=0.0005). Same doses in different positions within the hive have different final efficacy. The higher efficacy was registered when the dispensers were placed over brood combs and on the hive bottom. It is suggested that efficacy is related to dispenser position within the hive.

Animals↗
PubMed2003

Honeybee (Apis mellifera L.) mrjp gene family: computational analysis of putative promoters and genomic structure of mrjp1, the gene coding for the most abundant protein of larval food.

Mrjp1 gene belongs to the honeybee mrjp gene family encoding the major royal jelly proteins (MRJPs), secreted by nurse bees into the royal jelly. In this study, we have isolated the genomic clone containing the entire mrjp1 gene and determined its sequence. The mrjp1 gene sequence spans over 3038 bp and contains six exons separated by five introns. Seven mismatches between the mrjp1 gene sequence and two previously independently published cDNA sequences were found, but these differences do not lead to any change in the deduced amino acid sequence of MRJP1. With the aid of inverse polymerase chain reaction we obtained sequences flanking the 5' ends of other mrjp genes (mrjp2, mrjp3, mrjp4 and mrjp5). Putative promoters were predicted upstream of all mrjp genes (including mrjp1). The predicted promoters contain the TATA motif (TATATATT), highly conserved both in sequence and position. Ultraspiracle (USP) transcription factor (TF) binding sites in putative promoter regions and clusters of dead ringer TF binding sites upstream of these promoters were predicted computationally. We propose that USP, as a juvenile hormone (JH) binding TF, might possibly act as a mediator of mrjp expression in response to JH. Mrjp1's genomic locus is predicted to encode an antisense transcript, partially overlapping with five mrjp1 exons and entirely overlapping with the putative promoter and predicted transcriptional start point of mrjp1. This finding may shed light on the mechanisms of regulation of mrjps expression. Southern blot analysis of genomic DNA revealed that all so far known members of mrjp gene family (mrjp1, mrjp2, mrjp3, mrjp4 and mrjp5) are present as single-copy genes per haploid honeybee genome. Although MRJPs and the yellow protein of Drosophila melanogaster share a certain degree of similarity in aa sequence and although it has been shown that they share a common evolutionary origin, neither structural similarities in the gene organization, nor significant similarities between intron sequences of mrjp1 gene and fourteen yellow-like genes of D. melanogaster were found.

Animals↗
PubMed2001

Aging and development in social insects with emphasis on the honey bee, Apis mellifera L.

Honey bee colonies typically consist of about 20-40 thousand workers, zero to few thousand males (drones), depending on the time of year, and a single queen, the mother of the colony. Workers typically live 3-6 weeks during the spring and summer and can live about 4months during the winter. Queens are longer lived. Anecdotes of queens living 2-3years are not unusual, though they normally live less than a year in commercial hives. Little is known about the life span of drones. Queens develop from fertilized eggs that are not different from the eggs that develop into workers. Queens are, however, twice as large, have specialized anatomy, live much longer, and develop faster from egg to adult. All of these differences are derived from differences in larval rearing environment, primarily nutrition. The developmental trajectory of a female larva from worker into a queen can be determined as late as the third day of larval development, after this time the developmental pathway is fixed for a worker phenotype. The total time of larval development is only 5-6 days, therefore, just 2-3 days of differential feeding can lead to profound differences in development, and longevity. Workers undergo age development after they become adults. Workers usually initiate foraging behavior when they are 2-3 weeks old. The age at which a worker initiates foraging is a strong determinant of her length of life. This is presumed to be a result of the hazards of foraging, but natural senescence also occurs. Some bees remain in the nest and are never observed to forage, thereby outliving their forager sisters. Corresponding to this behavioral development are changes in the sizes of glands and the production of glandular products, increases in biogenic amine titers within the brain, an increase in the volume of specific regions of the brain, and changes in the neural system that affect perception of stimuli, and learning and memory. These age-related changes in behavior are regulated by intrinsic and extrinsic factors. Genetic variation has been demonstrated for many of these life history and behavioral traits. Selection and genome mapping studies have demonstrated relationships between the neural system, behavior, and life history traits.

Aging↗
PubMed1996

Inhibition of nitric oxide synthase impairs a distinct form of long-term memory in the honeybee, Apis mellifera.

Nitric oxide has been shown to be implicated in neural plasticity that underlies processes of learning and memory. In the honeybee, studies on the role of nitric oxide in associative olfactory learning reveal its specific function in memory formation. Inhibition of nitric oxide synthase during olfactory conditioning impairs a distinct long-term memory that is formed as a consequence of multiple learning trials. Acquisition or retrieval of memory or memory formation induced by a single learning trial is not affected by blocking of nitric oxide synthase. This finding provides a first step toward dissection of molecular mechanisms involved in memory formation, in general, and the special function of nitric oxide synthase in particular.

Animals↗
PubMed2002

Environmental and genetic influences on flight metabolic rate in the honey bee, Apis mellifera.

Flying honey bees demonstrate highly variable metabolic rates. The lowest reported values (approximately 0.3 Wg(-1)) occur in tethered bees generating the minimum lift to support their body weight, free-flying 2-day old bees, winter bees, or bees flying at high air temperatures (45 degrees C). The highest values (approximately 0.8 Wg(-1)) occur in foragers that are heavily loaded or flying in low-density air. In different studies, flight metabolic rate has increased, decreased, or remained constant with air temperature. Current research collectively suggests that this variation occurs because flight metabolic rates decrease at thorax temperatures above or below 38 degrees C. At 30 degrees C, approximately 30% of colonial energy is spent during typical foraging, so variation in flight metabolic rate can strongly affect colony-level energy balance. Higher air temperatures tend to increase colonial net gain rates, efficiencies and honey storage rates due to lower metabolic rates during flight and in the hive. Variation in flight metabolism has a clear genetic basis. Different genetic strains of honey bees often differ in flight metabolic rate, and these differences in flight physiology can be correlated with foraging effort, suggesting a possible pathway for selection effects on flight metabolism.

Animals↗
PubMed2000

Quantification and rapid metabolite identification in drug discovery using API time-of-flight LC/MS.

Liquid chromatography/mass spectrometry (LC/MS), utilizing a time-of-flight (TOF) mass analyzer, has been evaluated and applied to problems in bioanalysis for pharmacokinetics and drug metabolism. The data obtained by TOF MS differ from those obtained using quadrupole mass spectrometer instruments in that full-scan spectra can be routinely collected with greater sensitivity and speed. Both quantitative and qualitative information, including compound concentration in rat plasma and full-scan atmospheric pressure ionization mass spectra, are concurrently obtained. This approach has been used to characterize the disposition of several drug compounds that have been simultaneously dosed to rats in a cassette format. Quantitation limits in the 5-25 ng/mL range (approximately 20 nM) were obtained from nominal mass chromatograms (0.5 Da resolution). A reference lock mass was used to provide accurate mass measurement to reach third decimal place accuracy in the monoisotopic molecular weight. An improvement in quantitation limits was demonstrated after using accurate mass determinations. Several possible preliminary drug metabolites were confirmed or refuted, based on accurate mass. The trend of metabolite formation and clearance was qualitatively evaluated.

Animals↗