Seasonal variation in vegetation and pollen collected by honeybees in Thessaloniki,Greece

Pollen is important for the nutrition of honeybees and it is necessary for their survival and reproduction. In this study, we collected daily the pollen pellets from four colonies and also recorded the plants in flower in the area around the apiary, over a two‐year period. Field records revealed the presence of 204 species with Asteraceae, Fabaceae and Rosaceae being the most specious families. Although honey bees collected more than 140 pollen types, the main pollen sources (>60% of the total weight) came from less than ten taxa. The most important pollen types with respect to total weight were Sisymbrium irio, Papaver rhoeas, Verbascum sp., Polygonum aviculare, Zea mays and Olea europaea. The use of pollen traps proved a more accurate method to record the type and the foraging period during which the honeybees collect pollen, compared to field observations.     

Accumulating wing damage affects foraging decisions in honeybees (Apis mellifera L.)

Abstract.  1. Nectar-foraging honeybees ( Apis mellifera ) on lavender ( Lavandula stoechas ) appear to forage so as to maximise net energy return from foraging bouts; however, evidence from other studies suggests that foraging has a detrimental effect on survival, due at least in part to physiological deterioration of the flight mechanism. But foragers also acquire wing damage during foraging, which may increase foraging effort and reduce foraging lifespan.
2. The accumulation of damage over time and its effects on foraging flight and flower choice were studied in the field using a system in which the criteria for flower preference by foragers was known from previous work. Wing damage accumulated exponentially over time and resulted in foragers becoming less choosy about the flowers they visited.
3. Damage added experimentally contributed independently to the effect on choosiness. Effects of wing damage (natural and added experimentally) were also independent of those of a relative measure of age, which related in an inconsistent way to changes in foraging preferences.     

蜜蜂食物矿物质成分分析

分别应用电感耦合等离子体原子发射光谱法（ICP－AES）和重量法测定意大利蜜蜂ApismelliferaL．食物（蜂蜜和花粉）矿物质成分和灰分含量。小叶桉EucalyptustereticornisSmith蜂蜜和花粉分别含有16种和23种矿质元素,矿物质含量分别为0．122％和1．651％,灰分含量分别为0．22％和1．33％。野坝子ElsholtziarugulosaHemslL．蜂蜜含9种元素,矿物质和灰分含量分别为0．057％和0．06％。蜜蜂食物中含量过高的矿物质和多种有害元素的存在,可能是工矿区蜜蜂的致死因素。     

Adaptation of worker honeybees (Apis mellifera) to their alarm pheromones

ABSTRACT. Honeybees rapidly became adapted to synthetic alarm pheromone components dispensed within their hives, and were less; inclined to sting both unmarked targets and targets marked with the; alarm pheromone. The possible application to beekeeping is discussed.     

Egg marking pheromones of anarchistic worker honeybees (Apis mellifera)

In honeybees, worker policing via egg eating enforces functionalworker sterility in colonies with a queen and brood. It is thoughtthat queens mark their eggs with a chemical signal, indicatingthat their eggs are queen-laid. Worker-laid eggs lack this signaland are, therefore, eaten by policing workers. Anarchistic workerhoneybees have been hypothesized to circumvent worker policingby mimicking the queen egg-marking signal. We investigated thisphenomenon by relating chemical profiles of workers and theireggs to egg acceptability. We found that the ability of someworkers (anarchistic workers in queenright colonies and deviantworkers from a queenless colony) to lay more acceptable eggsis due to them producing significant amounts of queen-like estersfrom their Dufour's gland. These esters appear to be transferredto eggs during laying and increase egg survival. However, theseesters cannot be the normal queen egg-marking signal, as theyare generally absent from queen-laid eggs and only increasethe short-term persistence of worker-laid eggs, because only7–30% of anarchistic worker-laid eggs persisted to hatchingversus 91–92% of queen-laid eggs. All workers can producesome esters, but only workers that greatly increase their esterproduction lay more acceptable eggs. The production of estersappears to be a flexible response, as anarchistic workers rearedin queenless colonies did not increase their ester production,while some deviant workers in queenless colonies did increasetheir ester production.     

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 Dra I test based on the restriction of PCR products of the tRNAleu–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.     

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.     

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.     

Social synchronization of circadian rhythms of metabolism in honeybees (Apis mellifera)

ABSTRACT. Groups of honeybee workers ( Apis mellifera Linn.; Hymenoptera: Apidae) show endogenous circadian rhythms in metabolic activity. Workers entrained to two different photoperiods, when put together in a group, coordinate their individual metabolic activity cycles into a synchronized group oscillation. Either physical interaction among workers, or a low volatility contact pheromone, is implicated in the control of this oscillating system.     

Origin of honeybees (Apis mellifera L.) from the Yucatan peninsula inferred from mitochondrial DNA analysis

Honeybees (Apis mellifera L.) sampled at sites in Europe, Africa and South America were analysed using a mitochondrial DNA restriction fragment length polymorphism (RFLP) marker. These samples were used to provide baseline information for a detailed analysis of the process of Africanization of bees from the neotropical Yucatan peninsula of Mexico. Radical changes in mitochondrial haplotype (mitotype) frequencies were found to have occurred in the 13-year period studied. Prior to the arrival of Africanized bees (1986) the original inhabitants of the Yucatan peninsula appear to have been essentially of southeastern European origin with a smaller proportion having northwestern European ancestry. Three years after the migration of Africanized bees into the area (1989), only very low levels of maternal gene flow from Africanized populations into the resident European populations had occurred. By 1998, however, there was a sizeable increase in the proportion of African mitotypes in domestic populations (61%) with feral populations having 87% of mitotypes classified as African derived. The results suggest that the early stages of Africanization did not involve a rapid replacement of European with African mitotypes and that earlier studies probably overestimated the prevalence of African mitotypes.     

Mitochondrial gene frequencies in Africanized honeybees (Apis mellifera L.): Theoretical model and empirical evidence

A population genetical model is used to investigate the effects of queen and drone fitness and swarming ability on nuclear and mitochondrial (mt) DNA variation in honeybees. The analysis of both types of DNA is particularly useful for a genetic study of the Africanized bee problem in the Americas. Both an analytical model and a Monte Carlo simulation show that even if mtDNA proves to be selectively neutral, Africanized mitotypes are expected at high frequencies because of the more frequent swarming of Africanized honeybees. Since the fitness of Africanized drones is higher than that of European drones, European and African mitotypes are expected to be polymorphic and consequently unreliable as diagnostic tools to discriminate between the two types. Samples of Africanized honeybees in Brazil reveal high mtDNA polymorphisms as predicted by the theoretical models.     

Temporal variation in the genetic structure of a drone congregation area: an insight into the population dynamics of wild African honeybees (Apis mellifera scutellata)

The mating system of the honeybee ( Apis mellifera ) has been regarded as one of the most panmictic in the animal kingdom, with thousands of males aggregating in drone congregation areas (DCAs) that virgin queens visit to mate with tens of partners. Although males from many colonies gather at such congregations, the temporal changes in the colonies contributing drones remain unknown. Yet, changes in the DCAs' genetic structure will ultimately determine population gene flow and effective population size. By repeatedly sampling drones from an African DCA over a period of 3 years, we studied the temporal changes in the genetic structure of a wild honeybee population. Using three sets of tightly linked microsatellite markers, we were able to reconstruct individual queen genotypes with a high accuracy, follow them through time and estimate their rate of replacement. The number of queens contributing drones to the DCA varied from 12 to 72 and was correlated with temperature and rainfall. We found that more than 80% of these queens were replaced by mostly unrelated ones in successive eight months sampling intervals, which resulted in a clear temporal genetic differentiation of the DCA. Our results suggest that the frequent long-range migration of colonies without nest-site fidelity is the main driver of this high queen turnover. DCAs of African honeybees should thus be regarded as extremely dynamic systems which together with migration boost the effective population size and maintain a high genetic diversity in the population.     

西方蜜蜂和兰州熊蜂在设施桃园的访花偏好性比较

【目的】为了比较西方蜜蜂 Apis mellifera 和兰州熊蜂 Bombus lantschouensis 在设施桃园内对不同时期桃花的访花偏好性、以及这种偏好性与花粉活力和采集花粉花蜜之间的关系。【方法】记录2种蜂在温室桃园内访问早期花、中期花和晚期花的比例,测定桃花不同时期的花粉活力以及2种蜂携带的花粉活力,观察2种蜂采集花蜜和采集花粉的成功率,统计2种蜂访花过程中桃花所处的枝条数及植株数。【结果】桃花不同时期的花粉活力差异显著,早期花花药未开裂,花粉未释放,中期花花粉活力（58.3%）显著高于晚期花花粉活力（34.2%）（P<0.01）;西方蜜蜂更加偏好访问中期花,对中期花的访问率高达75.3%,显著高于兰州熊蜂对中期花的访问率（49.2%）（P<0.01）;西方蜜蜂携带的花粉活力（92.1%）显著高于兰州熊蜂携带的花粉活力（72.9%）,但是西方蜜蜂采集花粉和采集花蜜的成功率均低于兰州熊蜂（P<0.01）;在访问一定数量的桃花过程中,兰州熊蜂在设施桃园内访问的枝条数和植株数较多,分布范围较广（P<0.01）。【结论】和兰州熊蜂相比,西方蜜蜂对活力花粉的辨别能力更强,更加偏好访问花粉活力较高的花朵,这种偏好性导致其采集花粉花蜜的成功率降低。     

Phylogenetic analysis of Starmerella apis in honey bees (Apis mellifera)

Honey bees are among the most effective pollinators that promote plant reproduction. Bees are highly active in the pollen collection season, which can lead to the transmission of selected pathogens between colonies. The clade Starmerella comprises yeasts that are isolated mainly from bees and their environment. When visiting plants, bees can come into contact with Starmerella spp. The aim of this study was to determine the prevalence and phylogenetic position of S. apis in bee colonies. Bee colonies were collected from nine apiaries in three regions. Ten colonies were sampled randomly from each apiary, and pooled samples were collected from the central part of the hive in each colony. A total of 90 (100%) bee colonies from nine apiaries were examined. Starmerella apis was detected in 31 (34.44%) samples, but related species were not identified. The 18S rRNA amplicon sequences of S. apis were compatible with the GenBank sequences of Starmerella spp. from India, Japan, Syria, Thailand, and the USA. The amplicon sequences of S. apis were also 99.06% homologous with the sequences deposited in GenBank under accession numbers JX515988 and NG067631 .This is the first study to perform a phylogenetic analysis of S. apis in Polish honey bees.     

The Africanization of honeybees (Apis mellifera L.) of the Yucatan: a study of a massive hybridization event across time

Until recently, African and European subspecies of the honeybee (Apis mellifera L.) had been geographically separated for around 10,000 years. However, human-assisted introductions have caused the mixing of large populations of African and European subspecies in South and Central America, permitting an unprecedented opportunity to study a large-scale hybridization event using molecular analyses. We obtained reference populations from Europe, Africa, and South America and used these to provide baseline information for a microsatellite and mitochondrial analysis of the process of Africanization of the bees of the Yucatan Peninsula, Mexico. The genetic structure of the Yucatecan population has changed dramatically over time. The pre-Africanized Yucatecan population (1985) comprised bees that were most similar to samples from southeastern Europe and northern and western Europe. Three years after the arrival of Africanized bees (1989), substantial paternal gene flow had occurred from feral Africanized drones into the resident European population, but maternal gene flow from the invading Africanized population into the local population was negligible. However by 1998, there was a radical shift with both African nuclear alleles (65%) and African-derived mitochondria (61%) dominating the genomes of domestic colonies. We suggest that although European mitochondria may eventually be driven to extinction in the feral population, stable introgression of European nuclear alleles has occurred.     

The impact of pollen consumption on honey bee (Apis mellifera) digestive physiology and carbohydrate metabolism

Carbohydrate‐active enzymes play an important role in the honey bee (Apis mellifera) due to its dietary specialization on plant‐based nutrition. Secretory glycoside hydrolases (GHs) produced in worker head glands aid in the processing of floral nectar into honey and are expressed in accordance with age‐based division of labor. Pollen utilization by the honey bee has been investigated in considerable detail, but little is known about the metabolic fate of indigestible carbohydrates and glycosides in pollen biomass. Here, we demonstrate that pollen consumption stimulates the hydrolysis of sugars that are toxic to the bee (xylose, arabinose, mannose). GHs produced in the head accumulate in the midgut and persist in the hindgut that harbors a core microbial community composed of approximately 10⁸ bacterial cells. Pollen consumption significantly impacted total and specific bacterial abundance in the digestive tract. Bacterial isolates representing major fermentative gut phylotypes exhibited primarily membrane‐bound GH activities that may function in tandem with soluble host enzymes retained in the hindgut. Additionally, we found that plant‐originating β‐galactosidase activity in pollen may be sufficient, in some cases, for probable physiological activity in the gut. These findings emphasize the potential relative contributions of host, bacteria, and pollen enzyme activities to carbohydrate breakdown, which may be tied to gut microbiome dynamics and associated host nutrition.     

Male fitness of honeybee colonies (Apis mellifera L.)

Honeybees (Apis mellifera L.) have an extreme polyandrous mating system. Worker offspring of 19 naturally mated queens was genotyped with DNA microsatellites, to estimate male reproductive success of 16 drone producing colonies. This allowed for estimating the male mating success on both the colony level and the level of individual drones. The experiment was conducted in a closed population on an isolated island to exclude interferences of drones from unknown colonies. Although all colonies had produced similar numbers of drones, differences among the colonies in male mating success exceeded one order of magnitude. These differences were enhanced by the siring success of individual drones within the offspring of mated queens. The siring success of individual drones was correlated with the mating frequency at the colony level. Thus more successful colonies not only produced drones with a higher chance of mating, but also with a significantly higher proportion of offspring sired than drones from less successful colonies. Although the life cycle of honeybee colonies is very female centred, the male reproductive success appears to be a major driver of natural selection in honeybees.     

意大利工蜂前胃显微结构观察

通过解剖镜和扫描电子显微镜对意大利工蜂Apismellifera ligusticaL.前胃的形态结构进行了观察,发现前胃包括前胃瓣和前胃管两部分。前胃瓣是由4个瓣片环围而成,球形,在蜜囊中,每个瓣片的长度约为0.8mm,前端为三角形结构,可以运动,边长约为0.35mm,三角形的前缘有较长的毛形结构。在每个三角形顶端各有一个直径约为50μm瘤形突起。前胃瓣最大孔径为0.89～1.00mm,具有调整和控制食物进入中肠的功能。前胃管是一直径0.01～0.02mm的较为柔软的管道,插入中肠5mm,该结构可防止中肠食物的倒流。前胃瓣上有7种毛状结构,分布在前胃瓣的不同部位,该结构的功能是分离和过滤、捕捉和感觉功能。本研究为理解工蜂前胃在消化系统中的功能和作用以及昆虫形态学和昆虫分类学提供理论依据。     

Distribution and variability of deformed wing virus of honeybees (Apis mellifera) in the Middle East and North Africa

Three hundred and eleven honeybee samples from 12 countries in the Middle East and North Africa (MENA) (Jordan, Lebanon, Syria, Iraq, Egypt, Libya, Tunisia, Algeria, Morocco, Yemen, Palestine, and Sudan) were analyzed for the presence of deformed wing virus (DWV). The prevalence of DWV throughout the MENA region was pervasive, but variable. The highest prevalence was found in Lebanon and Syria, with prevalence dropping in Palestine, Jordan, and Egypt before increasing slightly moving westwards to Algeria and Morocco Phylogenetic analysis of a 194 nucleotide section of the DWV Lp gene did not identify any significant phylogenetic resolution among the samples, although the sequences did show consistent regional clustering, including an interesting geographic gradient from Morocco through North Africa to Jordan and Syria. The sequences revealed several clear variability hotspots in the deduced amino acid sequence, which furthermore showed some patterns of regional identity. Furthermore, the sequence variants from the Middle East and North Africa appear more numerous and diverse than those from Europe.     

Adaptive behaviour of honeybees (Apis mellifera) toward beetle invaders exhibiting various levels of colony integration

Social bees generally host fewer nest invaders than do ants and termites. This is potentially explained by the adaptive defensive strategies of host bees when faced with nest invaders exhibiting various levels of colony integration (based on adaptations to the nest habitat and frequency of nest inhabitation). In the present study, experiments are performed to determine the behaviour at the nest entrance of European honeybee guards Apis mellifera L. (Hymenoptera: Apidae) toward beetle invaders of various levels of behavioural integration into colonies. The species used to test this include Aethina tumida Murray (Coleoptera: Nitidulidae), which is regarded as a highly integrated, unwelcome guest (synechthran) or true guest (symphile); Lobiopa insularis Laporte (Coleoptera: Nitidulidae) and Epuraea luteola Erichson (Coleoptera: Nitidulidae) that are accidentals; and Carpophilus humeralis Fabricius (Coleoptera: Nitidulidae), Carpophilus hemipterus L. (Coleoptera: Nitidulidae) and Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), all of which are species that are not integrated into honeybee colonies. The responses of guard bees to a control bead also are noted. In general, bees ignore T. castaneum and E. luteola to a greater extent than other beetle species. Bees make contact with the black glass bead (a non‐aggressive behaviour) more than they do all beetle species. Bees treat A. tumida more defensively than they treat any other beetle species and the level of bee defensiveness varies by colony. These data suggest an adaptive heightened defensive response by bees toward the most integrated colony intruder but a significantly reduced level of response toward invaders representing all other levels of colony integration.