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At least 397 records · Page 22Linked to original sources

PubMed2002

Reproduction of Varroa destructor in worker brood of Africanized honey bees (Apis mellifera).

Reproduction and population growth of Varroa destructor was studied in ten naturally infested, Africanized honey bee (AHB) (Apis mellifera) colonies in Yucatan, Mexico. Between February 1997 and January 1998 monthly records of the amount of pollen, honey, sealed worker and drone brood were recorded. In addition, mite infestation levels of adult bees and worker brood and the fecundity of the mites reproducing in worker cells were determined. The mean number of sealed worker brood cells (10,070 +/- 1,790) remained fairly constant over the experimental period in each colony. However, the presence and amount of sealed drone brood was very variable. One colony had drone brood for 10 months and another for only 1 month. Both the mean infestation level of worker brood (18.1 +/- 8.4%) and adult bees (3.5 +/- 1.3%) remained fairly constant over the study period and did not increase rapidly as is normally observed in European honey bees. In fact, the estimated mean number of mites fell from 3,500 in February 1997 to 2,380 in January 1998. In May 2000 the mean mite population in the study colonies was still only 1,821 mites. The fertility level of mites in this study was much higher (83-96%) than in AHB in Brazil (25-57%). and similar to that found in EHB (76-94%). Mite fertility remained high throughout the entire study and was not influenced by the amount of pollen, honey or worker brood in the colonies.

Animals↗

PubMed2000

Quantitative analysis of risk sensitivity in honeybees (Apis mellifera) with variability in concentration and amount of reward.

Free-flying honeybees (Apis mellifera) were trained in a series of experiments designed to look for evidence of risk sensitivity in foraging for sucrose solution. The suitability of the choice method used was established in 3 preliminary experiments with differences in concentration, amount, and probability of reward. Of 5 subsequent experiments in which 2 alternatives provided the same mean concentration of sucrose solution with different variance, 3 showed risk indifference, and 2 showed risk aversion (preference for consistent reward). Of 2 final experiments in which the alternatives provided the same mean amount of sucrose solution with different variance, both showed risk aversion. Performance could be simulated quantitatively with a simple choice model developed by P. A. Couvillon and M. E. Bitterman (1991) to account for the results of a wide range of previous experiments on discriminative learning in honeybees.

Animals↗

PubMed1991

Learning by honeybees (Apis mellifera) on arrival at and departure from a feeding place.

The question of when in the course of a visit to a feeding place foraging honeybees (Apis mellifera) learn about its location was studied in Experiment 1 by moving the animals a short distance after they arrived and began to feed. A preference for the arrival place developed, although less rapidly than in control animals for which the arrival and departure places were the same. In Experiments 2-5, a distinctive object was used to define the location of the feeding place. When the object was removed after arrival or introduced only after arrival, the animals learned less about its color and shape than did control animals for which it was present throughout each visit. The results contradict the claim that honeybees learn about certain characteristics of a feeding place only on arrival and about others only on departure.

Animals↗

PubMed1992

Learning in honeybees (Apis mellifera) as a function of sucrose concentration.

Foraging honeybees (Apis mellifera) were trained with 2 successively presented targets differing in color or odor, one of which always contained a 5-microliters drop of 50% sucrose solution and the other, a 5-microliters drop of 20% sucrose solution. Latency of response to each target was measured during the training, and at the conclusion, preference was measured in an unrewarded choice test. Analysis of the latencies showed both a prospective effect (faster response to the 50% target than to the 20% target) and a nonassociative retrospective effect (faster response after leaving the 20% target than after leaving the 50% target) reminiscent of the frustration effect in rats. The results both for prospective latency and for choice can be understood on the simple theory that the attractiveness of a target depends on the strength of its association with sucrose and that the effect of concentration is on asymptotic strength.

Animals↗

PubMed1992

Simultaneous conditioning in honeybees (Apis mellifera).

Honeybees (Apis mellifera) were classically conditioned with odor as conditioned stimulus (CS), sucrose as unconditioned stimulus (US), and proboscis extension as response. The purpose of Experiment 1 (Ns = 26 and 27) was to look for facilitation of forward conditioning by CS-US overlap, but rapid conditioning without overlap left little room for improvement. In 2 further experiments, CS and US were simultaneous, and response to odor alone was measured in subsequent tests. In Experiment 2, a Simultaneous group (N = 25) responded more to the training odor than did an Unpaired control group (N = 25). In Experiment 3, a differentially conditioned Simultaneous group (N = 29) responded more to an odor paired with sucrose in training (S+) than to an odor presented alone (S-). The implications of the results for the problem of the role of amount of reward in honeybee learning are considered.

Animals↗

PubMed1994

Evidence for spatial working memory in honeybees (Apis mellifera).

Spatial working memory (the ability to represent multiple locations in a flexible, dynamic manner) has been studied in a range of vertebrate species. The results of 3 experiments indicate that this ability also exists in at least one invertebrate (honeybees; Apis mellifera). Individual honeybees collected sugar solution from a matrix of 6 locations. They avoided revisits to locations previously depleted of solution more accurately than expected by chance. The results rule out several nonmemorial explanations for this ability, and it is therefore best explained by a spatial working memory system that allows discrimination of previously visited locations from those not yet visited. These results substantially expand the range of species in which spatial working memory has been demonstrated.

Animals↗

PubMed2000

Heritable variation for latent inhibition and its correlation with reversal learning in honeybees (Apis mellifera).

Latent inhibition (LI) in honeybees (Apis mellifera) was studied by using a proboscis extension response conditioning procedure. Individual queens, drones, and workers differed in the degree to which they revealed LI. The authors hypothesized that individual differences would have a substantial genetic basis. Two sets of progeny were established by crossing virgin queens and individual drones, both of which had been selected for differential expression of inhibition. LI was stronger in the progeny from the queens and drones that had shown greater inhibition. The expression of LI was also dependent on environmental factors that are most likely associated with age, foraging experience outside of the colony, or both. Furthermore, there was a correlated response in the speed at which progeny reversed a learned discrimination of 2 odors. These genetic analyses may reveal underlying mechanisms that these 2 learning paradigms have in common.

Animals↗

PubMed2003

Delayed alternation in honeybees (Apis mellifera).

Previous experiments with honeybees (Apis mellifera) failed to show learned control of performance by short-ten memory. In this study, honeybees were trained with an improved technique to choose 1 of 2 colors that was either the same as a recently rewarded sample (perseveration) or different (alteration). Because any increase in associative strength stemming from the sample experience would tend to promote perseveration and contravene alternation, the equal difficulty of the 2 tasks suggests that the role played by the sample was primarily discriminative. The animals remembered on each trial the immediately preceding experience with reward and learned to use that information appropriately. These new results extend the list of what may well be fundamental similarities in the learning of vertebrates and honeybees.

Animals↗

PubMed2001

Enantioselectivity of odor perception in honeybees (Apis mellifera carnica).

The authors tested the ability of 60 free-flying honeybees (Apis mellifera carnica) to discriminate a conditioning odor from an array of 26 simultaneously presented substances. The stimuli included 10 pairs of enantiomers and 6 essential oils. The bees (a) significantly distinguished between 98% of the 540 odor pairs tested, thus showing an excellent overall discrimination performance, and (b) were able to discriminate between the optical isomers of limonene, alpha-pinene, beta-citronellol, menthol, and carvone but failed to distinguish between the (+)- and (-)-forms of alpha-terpineol, camphor, rose oxide, fenchone, and 2-butanol. The findings support the assumptions that enantioselective molecular odor receptors may exist only for some volatile enantiomers and that insects and mammals may share common principles of odor quality perception, irrespective of their completely differing repertoires of olfactory receptors.

Animals↗

PubMed2003

Regional brain variations of cytochrome oxidase staining during olfactory learning in the honeybee (Apis mellifera).

Regional brain variations of cytochrome oxidase (CO) staining were analyzed in the honeybee (Apis mellifera) after olfactory conditioning of the proboscis extension reflex. Identification of brain sites where stimuli converge was done by precise image analysis performed in antennal lobes (AL) and mushroom bodies (MB). In Experiment 1, bees received 5 odorant stimulations that induced a transient decrease of CO activity in the lateral part of the AL. In Experiment 2, bees were trained with 5-trial olfactory conditioning. CO activity transiently increased in the lips of the MB calyces. There was also a delayed increase in the lateral part of the AL. An olfactory stimulus presented alone and an odor paired to a sucrose stimulation are treated by different pathways, including both AL and MB.

Animals↗

PubMed1992

The antigenicity of the carbohydrate moiety of an insect glycoprotein, honey-bee (Apis mellifera) venom phospholipase A2. The role of alpha 1,3-fucosylation of the asparagine-bound N-acetylglucosamine.

A rabbit polyclonal antiserum raised against honey-bee (Apis mellifera) venom phospholipase A2 (PLA2) contains antibodies that react exclusively with its glycosylated variants and cross-react with plant glycoproteins. The interaction of anti-(horseradish peroxidase) antiserum with PLA2 suggests the existence of a carbohydrate determinant common to both glycoproteins. E.l.i.s.a. binding and inhibition experiments, employing glycoproteins and glycopeptides of plant and animal origin with known N-glycan structures, in combination with chemical and enzymic deglycosylation, identified alpha 1,3-fucosylation of the asparagine-bound N-acetylglucosamine as the antigenic determinant. This fucose residue is present in the N-glycan of PLA2 and is frequently found in plant glycoproteins, whereas mammalian glycoproteins lack this modification.

Acetylglucosamine↗

PubMed1999

Phylogeographical autocorrelation of phenotypic evolution in honey bees (Apis mellifera L.).

The analysis of phenotypic divergence among local populations within a species has been traditionally performed in a spatial context, although advances in genetic analysis using mtDNA have permitted a simultaneous evaluation of geographical and historical patterns of variation, so-called phylogeographical analysis. In this paper, we combine these two dimensions of variation (geographical space and phylogenetic history) to evaluate patterns of phenotypic evolution in honey bees (Apis mellifera L.). Data on 39 phenotypic traits, derived from 417 colonies grouped into 14 subspecies, were analysed using autocorrelation methods. Mantel tests indicated that the relationship between phenotypic divergence, estimated by Euclidean distances among subspecies' morphological centroids, was significant both when compared to geographical distance (r=0.371; P < 0.01) and to genetic distance (estimated as sequence divergence (%) in a mtDNA region encompassing part of the NADH dehydrogenase subunit 2 and isoleucine transfer RNA (r=0.329; P < 0.01)). For the analysis of each trait, the effects of the geographical co-ordinates (latitude and longitude of subspecies geographical range) and of the phylogenetic patterns (defined by eigenvectors of the genetic distance matrix) on phenotypic variation were simultaneously analysed using an extension of a recently developed model, called Phylogenetic Eigenvector Regression (PVR). In general terms, the partial regression slopes indicated that the variation in the characters traditionally associated with adaptive processes, such as body and wing size, were better explained by geographical position. However, characters usually thought to be neutral, such as wing venation angle, were more associated with phylogeny. This is expected because PVR can be interpreted as a partition model, in which adaptive variation tends to be independent of phylogeny (and, in this case, associated with geography). In addition, the first principal component derived from the expected values of the model for each trait, which can be interpreted as the phenotypic variation predicted by phylogeny, is more structured in a north-south cline than are the original data, supporting an adaptive interpretation. The phylogeographical autocorrelation analyses performed in this study show that different traits are more related to one of the two dimensions of variation (geography and phylogeny), and these patterns can furnish insights into the nature of phenotypic evolution in these organisms.

Animals↗

PubMed2000

MtDNA variation in Apis cerana populations from the Philippines.

The cavity-nesting honeybee Apis cerana occurs in Asia, from Afghanistan to China and from Japan to southern Indonesia. Based on morphometric values, this species can be grouped into four subspecies: A. c. cerana, A. c. indica, A. c. japonica and A. c. himalaya. In order to analyse the geographical variability of A. c. indica from the Philippine Islands, 47 colonies from different locations in three of the larger islands (Mindanao, Luzon and Palawan) and four of the Visayan Islands (Panay, Negros, Cebu and Leyte) were studied. Genetic variation was estimated by restriction and sequence analysis of PCR-amplified fragments of the tRNAleu-COII region. We found four different haplotypes, Ce1, Ce2, Ce3 and Ce4, that discriminate among the bee populations from different islands. The Ce1 haplotype is present in Mindanao and Visayan Islands, Ce2 is restricted to Luzon, and both Ce3 and Ce4 are only present in Palawan. Phylogenetic analysis of the sequences shows a great intraspecific variability, is in accordance with the geological history of these islands and partially agrees with some previous morphological and molecular studies.

Animals↗

PubMed2000

Sperm-mediated transformation of the honey bee, Apis mellifera.

Our primary objective was to identify techniques to transform the genome of the honey bee (Apis mellifera) with foreign DNA constructs. The strategy we adopted was to linearize foreign DNA and introduce it with sperm during the instrumental insemination of virgin queen honey bees. We analysed extracts from larvae within the same cohort and isolated the predicted fragment by means of PCR amplification of genomic DNA. Larvae that carried the construct also expressed the introduced DNA. We propagated several transgenic lines for up to three generations, which demonstrates its heritability. Once carried by a queen, the construct can be detected in that queen's larvae over several months. However, there was no evidence of integration of the construct, at least as determined by genomic Southern analysis. Nevertheless, this demonstrates the general viability of the technique for introduction of DNA, and it should be augmented by further use of transposable elements that enhance integration.

Animals↗

PubMed2003

Identification and localization of the nicotinic acetylcholine receptor alpha3 mRNA in the brain of the honeybee, Apis mellifera.

The nicotinic acetylcholine receptors are ligand-gated ion channels responsible for rapid neurotransmission and are target sites for pesticides in insects. In the honeybee Apis mellifera, pharmacological and electrophysiological studies have shown that different nicotinic acetylcholine receptor subtypes may exist in the brain. Here, we have identified a honeybee cDNA that encodes a 537 amino acid protein with features typical of nicotinic acetylcholine receptor alpha subunit, and sequence homology to human alpha3. In situ hybridization on cryosections shows that the Apisalpha3 mRNA is differently expressed in larvae and adult. In larvae, Apisalpha3 mRNA expression is restricted to the suboesophageal ganglia. In adult, it is further expressed in the optic lobes, the dorsal lobes, the antennal lobes and the calyces of mushroom bodies. Together our results suggest that Apisalpha3 shows a controlled expression pattern during development.

Amino Acid Sequence↗

PubMed2003

Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus.

AIMS: The antibacterial activity against Staphylococcus aureus of honey and propolis produced by Apis mellifera and Tetragonisca angustula was evaluated. Secondary aims included the study of the chemical composition of propolis and honey samples and its relationship with antibacterial activity against S. aureus. METHODS AND RESULTS: The antibacterial activity of honey and propolis was determined by the method of macrodilution. The minimum inhibitory concentration (MICs) of A. mellifera honey ranged from 126.23 to 185.70 mg ml(-1) and of T. angustula from 142.87 to 214.33 mg ml(-1). For propolis, the MIC ranged from 0.36 to 3.65 mg ml(-1) (A. mellifera) and from 0.44 to 2.01 mg ml(-1) (T. angustula). Honey and propolis were evaluated by high-performance liquid chromatography. Some typical compounds of Brazilian propolis were also identified in honey samples. Principal component analysis revealed that the chemical composition of honey and propolis samples was distinct based on the geographical location of the samples. CONCLUSIONS: Propolis samples had higher antibacterial activity against S. aureus when compared with honey. However, both propolis and honey samples had antibacterial against S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: These antimicrobial properties would warrant further studies on the clinical applications of propolis and honey against S. aureus.

Animals↗

PubMed1998

Mitochondrial DNA variability in the Canary Islands honeybees (Apis mellifera L.).

The mitochondrial DNA (mtDNA) of individuals from 79 colonies of Apis mellifera from five Canary Islands was studied using the DraI test based on the restriction of PCR products of the tRNA(leu)-COII intergenic region. Five haplotypes of the African (A) lineage and one of the west European (C) lineage were found. The haplotypes A14 and A15 are described for the first time. These haplotypes have a new P sequence named P1. The wide distribution and high frequency of haplotype A15 suggest that it is characteristic of the Canarian Archipelago. Sources of haplotype variability of honeybee mtDNA in the Canary Islands (waves of colonization from Africa, queen importations, habitat diversification) are discussed.

Animals↗

PubMed2000

Hybrid origins of honeybees from italy (Apis mellifera ligustica) and sicily (A. m. sicula).

The genetic variability of honeybee populations Apis mellifera ligustica, in continental Italy, and of A. m. sicula, in Sicily, was investigated using nuclear (microsatellite) and mitochondrial markers. Six populations (236 individual bees) and 17 populations (664 colonies) were, respectively, analysed using eight microsatellite loci and DraI restriction fragment length polymorphism (RFLP) of the cytochrome oxidase I (COI)-cytochrome oxidase II (COII) region. Microsatellite loci globally confirmed the southeastern European heritage of both subspecies (evolutionary branch C). However, A. m. ligustica mitochondrial DNA (mtDNA) appeared to be a composite of the two European (M and C) lineages over most of the Italian peninsula, and only mitotypes from the African (A) lineage were found in A. m. sicula samples. This demonstrates a hybrid origin for both subspecies. For A. m. ligustica, the most widely exported subspecies, this hybrid origin has long been obscured by the fact that in the main area of queen production (from which most of the previous ligustica bee samples originated) the M mitochondrial lineage is absent, whereas it is present almost everywhere else in Italy. This presents a new view of the evolutionary history of European honeybees. For instance, the Iberian peninsula was considered as the unique refuge for the M branch during the quaternary ice periods. Our results show that the Apennine peninsula played a similar role. The differential distribution of nuclear and mitochondrial markers observed in Italy seems to be a general feature of introgressed honeybee populations. Presumably, it stems from the social nature of the species in which both genome compartments are differentially affected by the two (individual and colonial) reproduction levels.

Alleles↗