European Honey Bee Apis Mellifera Research Articles

Immunosenescence and resistance to parasite infection in the honey bee, Apis mellifera

Immunosenescence, the systemic reduction of immune efficiency with age, is increasingly recognised as having important implications for host-parasite dynamics. Changes in the immune response can impact on the ability of an individual to resist or moderate parasite infection, depending on how and when it encounters a parasite challenge. Using the European honey bee Apis mellifera and its microsporidian parasite Nosema ceranae, we investigated the effects of host age on the ability to resist parasite infection and on baseline immunocompetence, assessed by quantifying constitutive (PO) and potential levels (PPO) of the phenoloxidase immune enzyme as general measures of immune function. There was a significant correlation between the level of general immune function and infection intensity, but not with survival, and changes in immune function with age correlated with the ability of individuals to resist parasite infection. Older individuals had better survival when challenged with a parasite than younger individuals, however they also had more intense infections and lower baseline immunocomptence. The ability of older individuals to have high infection intensities yet live longer, has potential consequences for parasite transmission. The results highlight the need to consider age in host-parasite studies and show the importance of choosing the correct measure when assaying invertebrate immunity.

Honey loading for pollen collection: regulation of crop content in honeybee pollen foragers on leaving hive.

Before foraging honeybees leave the hive, each bee loads its crop with some amount of honey "fuel" depending on the distance to the food source and foraging experience. For pollen collection, there is evidence that foragers carry additional honey as "glue" to build pollen loads. This study examines whether pollen foragers of the European honeybee Apis mellifera regulate the size of the crop load according to food-source distances upon leaving the hive and how foraging experience affects load regulation. The crop contents of bees foraging on crape myrtle Lagerstroemia indica, which has no nectary, were larger than those foraging on nectar from other sources, confirming a previous finding that pollen foragers carry glue in addition to fuel honey from the hive. Crop contents of both waggle dancers and dance followers showed a significant positive correlation with waggle-run durations. These results suggest that bees carry a distance-dependent amount of fuel honey in addition to a fixed amount of glue honey. Crop contents on leaving the hive were statistically larger in dancers than followers. Based on these results, we suggest that pollen foragers use information obtained through foraging experience to adjust crop contents on leaving the hive.

Lactobacillus bombi sp. nov., from the digestive tract of laboratory-reared bumblebee queens (Bombus terrestris).

Three bacterial strains belonging to the genus Lactobacillus were isolated from the digestive tracts of laboratory-reared bumblebee queens (Bombus terrestris) using MRS agar under anaerobic conditions. The isolates were identified according to 16S rRNA gene sequence analysis as undescribed members of the genus Lactobacillus, with the highest 16S rRNA gene sequence similarity (96.9 %) to the uncharacterized bacterial strain Lactobacillus sp. Mboho2r2 isolated from the stomach of a European honeybee (Apis mellifera). Lactobacillus tucceti was found to be the closest related species with a validly published name, with 92.9 % 16S rRNA gene sequence similarity to the type strain. However, phylogenetic analyses based on different markers revealed that this species is phylogenetically very distant from the novel strains. The DNA G+C content of the proposed type strain BTLCH M1/2(T) is 37.8 mol%. The fatty acids C(19 : 1)ω6c and/or C(19 : 0) cyclo ω10c/19ω6, C(18 : 1)ω9c and C(16 : 0) were predominant in all strains. Diphosphatidylglycerol, phosphatidylglycerol, a phospholipid, seven glycolipids and two phosphoglycolipids were detected in the novel strains. Growth was observed at 47 °C. The peptidoglycan type A4α L-Lys-D-Asp was determined for strain BTLCH M1/2(T). Genotypic characteristics and phylogenetic analyses based on the phylogenetic markers hsp60, pheS, rpoA and tuf as well as phenotypic characteristics and the results of chemotaxonomic analyses confirmed that the new isolates belong to a novel species of the genus Lactobacillus, for which the name Lactobacillus bombi sp. nov. is proposed. The type strain is BTLCH M1/2(T) ( = DSM 26517(T) = CCM 8440(T)).

Typing of Melissococcus plutonius isolated from European and Japanese honeybees suggests spread of sequence types across borders and between different Apis species

Melissococcus plutonius is an important pathogen of honeybee larvae and causes European foulbrood (EFB) not only in European honeybees (Apis mellifera) but also in other native honeybees. We recently confirmed the first EFB case in Japanese native honeybees (Apis cerana japonica) and isolated M. plutonius from this case. In this study, to obtain a better understanding of the ecology of M. plutonius and the epidemiology of EFB, we analyzed M. plutonius isolates that originated from European and Japanese honeybees in Japan using an existing multilocus sequence typing scheme. These analyzed Japanese isolates were resolved into six sequence types (STs), three of which were novel STs. Among these six STs, ST3 and ST12 were the two most common and found in isolates from both European and Japanese honeybees (or their environment). Moreover, these two STs were identified not only in Japan but also in other countries, suggesting the spread of some STs across borders and different honeybee species.

PLANNED HONEY BEE POLLINATION IN LITCHI (LITCHI CHINENSIS SONN.) - A NEW PRODUCTION STRATEGY FOR ENHANCING FRUIT YIELD AND QUALITY IN INDIA

ISHS IV International Symposium on Lychee, Longan and Other Sapindaceae Fruits PLANNED HONEY BEE POLLINATION IN LITCHI (LITCHI CHINENSIS SONN.) - A NEW PRODUCTION STRATEGY FOR ENHANCING FRUIT YIELD AND QUALITY IN INDIA

Molecular epidemiology and population structure of the honey bee brood pathogen Melissococcus plutonius.

Melissococcus plutonius is the causative agent of European foulbrood (EFB), which is a serious brood disease of the European honey bee (Apis mellifera). EFB remains a threat because of a poor understanding of disease epidemiology. We used a recently published multi-locus sequence typing method to characterise 206 M. plutonius isolates recovered from outbreaks in England and Wales over the course of 2 years. We detected 15 different sequence types (STs), which were resolved by eBURST and phylogenetic analysis into three clonal complexes (CCs) 3, 12 and 13. Single and double locus variants within CC3 were the most abundant and widespread genotypes, accounting for 85% of the cases. In contrast, CCs 12 and 13 were rarer and predominantly found in geographical regions of high sampling intensity, consistent with a more recent introduction and localised spread. K-function analysis and interpoint distance tests revealed significant geographical clustering in five common STs, but pointed to different dispersal patterns between STs. We noted that CCs appeared to vary in pathogenicity and that infection caused by the more pathogenic variants is more likely to lead to honey bee colony destruction, as opposed to treatment. The importance of these findings for improving our understanding of disease aetiology and control are discussed.

BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure

Summary A notable increase in failure of managed European honeybee Apis mellifera L. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact. In silico experiments offer a fast and cost‐effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics.We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa‐transmitted viruses and allows foragers in an agent‐based foraging model to collect food from a representation of a spatially explicit landscape.We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested. Synthesis and applications. BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee colony dynamics.

Structural and functional differences in the antennal olfactory system of worker honey bees of Apis mellifera and Apis cerana

Olfactory cues are important sensory modalities on individual discrimination, perception, and efficient orientation to food sources in most insects. In honey bees, which are well known as eusocial insects, olfactory cues are mainly used to maintain a colony. Although much research has been reported on olfactory systems in honey bee olfaction, little is known about the differences between two major honey bee species, the European honey bee Apis mellifera and the Asian honey bee Apis cerana. In order to understand the differences of olfactory characteristics in the two species, we compared the distribution of sensory hairs on the antennae and antennal olfactory responses, using electron microscopy, electrophysiological recording and molecular expression level of odorant receptors. Our present study demonstrated that the antennae of A. cerana have more olfactory sensilla than A. mellifera, responding more strongly to various floral volatile compounds. At the molecular level, olfactory co-receptor (Orco), which makes heterodimers with other conventional olfactory receptors, is more abundantly expressed in the antenna of A. cerana than of A. mellifera. These findings extend our understanding of the olfactory systems and behavioral responses to various ecological and biological signals in two closely related honey bee species.

Histopathological findings of the midgut in European honey bee (Apis Mellifera L.) naturally infected by Nosema spp.

Introduction Nosemosis is a highly dangerous disease of adult honey bees, caused by Nosema species [1]. The genus Nosema includes protozoan parasites of the microsporidian class that are obligate intracellular parasites, transmitted between hosts as spores and have unique organs for cell invasion [2]. Nosema is able to infect all colony

Genetic integrity of the Dark European honey bee (Apis mellifera mellifera) from protected populations: a genome-wide assessment using SNPs and mtDNA sequence data

SummaryThe recognition that the Dark European honey bee, Apis mellifera mellifera, is increasingly threatened in its native range has led to the establishment of conservation programmes and protected areas throughout western Europe. Previous molecular surveys showed that, despite management strategies to preserve the genetic integrity of A. m. mellifera, protected populations had a measurable component of their gene pool derived from commercial C-lineage honey bees. Here we used both sequence data from the tRNAleu-cox2 intergenic mtDNA region and a genome-wide scan, with over 1183 single nucleotide polymorphisms (SNPs), to assess genetic diversity and introgression levels in several protected populations of A. m. mellifera, which were then compared with samples collected from unprotected populations. MtDNA analysis of the protected populations revealed a single colony bearing a foreign haplotype, whereas SNPs showed varying levels of introgression ranging from virtually zero in Norway to about 14% in Denmark. Introgression overall was higher in unprotected (30%) than in protected populations (8%), and is reflected in larger SNP diversity levels of the former, although opposite diversity levels were observed for mtDNA. These results suggest that, despite controlled breeding, some protected populations still require adjustments to the management strategies to further purge foreign alleles, which can be identified by SNPs.

Genetic variability of the neogregarine Apicystis bombi, an etiological agent of an emergent bumblebee disease.

The worldwide spread of diseases is considered a major threat to biodiversity and a possible driver of the decline of pollinator populations, particularly when novel species or strains of parasites emerge. Previous studies have suggested that populations of introduced European honeybee (Apis mellifera) and bumblebee species (Bombus terrestris and Bombus ruderatus) in Argentina share the neogregarine parasite Apicystis bombi with the native bumblebee (Bombus dahlbomii). In this study we investigated whether A. bombi is acting as an emergent parasite in the non-native populations. Specifically, we asked whether A. bombi, recently identified in Argentina, was introduced by European, non-native bees. Using ITS1 and ITS2 to assess the parasite’s intraspecific genetic variation in bees from Argentina and Europe, we found a largely unstructured parasite population, with only 15% of the genetic variation being explained by geographic location. The most abundant haplotype in Argentina (found in all 9 specimens of non-native species) was identical to the most abundant haplotype in Europe (found in 6 out of 8 specimens). Similarly, there was no evidence of structuring by host species, with this factor explaining only 17% of the genetic variation. Interestingly, parasites in native Bombus ephippiatus from Mexico were genetically distant from the Argentine and European samples, suggesting that sufficient variability does exist in the ITS region to identify continent-level genetic structure in the parasite. Thus, the data suggest that A. bombi from Argentina and Europe share a common, relatively recent origin. Although our data did not provide information on the direction of transfer, the absence of genetic structure across space and host species suggests that A. bombi may be acting as an emergent infectious disease across bee taxa and continents.

A Causal Analysis of Observed Declines in Managed Honey Bees (Apis mellifera)

ABSTRACT The European honey bee (Apis mellifera) is a highly valuable, semi-free-ranging managed agricultural species. While the number of managed hives has been increasing, declines in overwinter survival, and the onset of colony collapse disorder in 2006, precipitated a large amount of research on bees’ health in an effort to isolate the causative factors. A workshop was convened during which bee experts were introduced to a formal causal analysis approach to compare 39 candidate causes against specified criteria to evaluate their relationship to the reduced overwinter survivability observed since 2006 of commercial bees used in the California almond industry. Candidate causes were categorized as probable, possible, or unlikely; several candidate causes were categorized as indeterminate due to lack of information. Due to time limitations, a full causal analysis was not completed at the workshop. In this article, examples are provided to illustrate the process and provide preliminary findings, using three candidate causes. Varroa mites plus viruses were judged to be a “probable cause” of the reduced survival, while nutrient deficiency was judged to be a “possible cause.” Neonicotinoid pesticides were judged to be “unlikely” as the sole cause of this reduced survival, although they could possibly be a contributing factor.

Viral Infection Affects Sucrose Responsiveness and Homing Ability of Forager Honey Bees, Apis mellifera L.

Honey bee health is mainly affected by Varroa destructor, viruses, Nosema spp., pesticide residues and poor nutrition. Interactions between these proposed factors may be responsible for the colony losses reported worldwide in recent years. In the present study, the effects of a honey bee virus, Israeli acute paralysis virus (IAPV), on the foraging behaviors and homing ability of European honey bees (Apis mellifera L.) were investigated based on proboscis extension response (PER) assays and radio frequency identification (RFID) systems. The pollen forager honey bees originated from colonies that had no detectable level of honey bee viruses and were manually inoculated with IAPV to induce the viral infection. The results showed that IAPV-inoculated honey bees were more responsive to low sucrose solutions compared to that of non-infected foragers. After two days of infection, around 107 copies of IAPV were detected in the heads of these honey bees. The homing ability of IAPV-infected foragers was depressed significantly in comparison to the homing ability of uninfected foragers. The data provided evidence that IAPV infection in the heads may enable the virus to disorder foraging roles of honey bees and to interfere with brain functions that are responsible for learning, navigation, and orientation in the honey bees, thus, making honey bees have a lower response threshold to sucrose and lose their way back to the hive.

Evaluation of Inflorescence Visitors as Pollinators of <I>Echinacea angustifolia</I> (Asteraceae): Comparison of Techniques

Inflorescences (heads or capitula) of the putative self-incompatible species, purple coneflower (Echinacea angustifolia (DC) Cronq. (Asteraceae)), were visited by insects representing the Coleoptera, Diptera, Hymenoptera, and Lepidoptera, in accordance with a generalist pollination syndrome. Measurement of the effectiveness of insect species as pollinators was accomplished by permitting solitary visits to receptive, central disc florets of virgin (previously bagged) heads. Four parameters were quantified: total stigmatic pollen load and proportion of pollen grains germinated, numbers of pollen tubes at style bases, and percentages of total receptive florets that had retracted (shrivelled) styles. Quantifying total and germinated pollen grains proved ineffective, partly owing to the tendency of self-pollen to initiate pollen tubes. The most effective pollinators were Apidae, especially bumble bees (Bombus spp.) and the European honey bee (Apis mellifera L.) (mean: 39 - 61% of styles retracted). Other noteworthy pollinators were cloudless sulfur butterflies (Phoebis sennae L.--Pieridae; mean 47% of style bases with pollen tubes), golden blister beetles (Epicauta ferruginea Say--Meloidae; 44%), and grasshopper bee flies (Systoechus vulgaris Loew--Bombyliidae; 22%). Sunflower leafcutter bees (Megachile pugnata Say) were less effective (4% of styles retracted). Promisingly, analysis of the proportion of retracted styles provided similar results to the established technique of pollen-tube quantification, but had the significant advantages of being completed more rapidly, without a microscope, and in the field. The quantitative technique of retracted-style analysis appears well suited for prompt measurement of inflorescence-visiting insects as pollinators of many asteraceans.

Effects of the organic acids produced by a lactic acid bacterium in Apis mellifera colony development, Nosema ceranae control and fumagillin efficiency

The European honey bee Apis mellifera is known to be affected by many parasites and pathogens that have great impact over the insect development. Among parasites affecting bee health, Nosema ceranae is one of the main biotic factors affecting colony populations. As honey bee populations decline, interest in pathogenic and mutualistic relationships between bees and microorganisms has increased. The main goal of the current study was to assess the effect of the oral administration of the metabolites produced by Lactobacillus johnsonii CRL1647 (mainly organic acids) supplemented in syrup, on: (I) N. ceranae sporulation dynamics before and after fumagillin application, and (II) performance of A. mellifera colonies. Different experiments were conducted to evaluate the effects of these bacterial metabolites on bees: in vitro administration revealed no toxic effects against bees. Colonies fed with the lactic acids incremented their beehive population and also the amount of fat bodies per bee. Finally, the organic acids reduced the intensity of the pathogen after the second application of treatment as well as enhanced the fumagillin efficiency. This study provides important information for the development of new control substances against nosemosis.

A Rapid Survey Technique for <I>Tropilaelaps</I> Mite (Mesostigmata: Laelapidae) Detection

Parasitic Tropilaelaps (Delfinado and Baker) mites are a damaging pest of European honey bees (Apis mellifera L.) in Asia. These mites represent a significant threat if introduced to other regions of the world, warranting implementation of Tropilaelaps mite surveillance in uninfested regions. Current Tropilaelaps mite-detection methods are unsuitable for efficient large scale screening. We developed and tested a new bump technique that consists of firmly rapping a honey bee brood frame over a collecting pan. Our method was easier to implement than current detection tests, reduced time spent in each apiary, and minimized brood destruction. This feasibility increase overcomes the test's decreased rate of detecting infested colonies (sensitivity; 36.3% for the bump test, 54.2% and 56.7% for the two most sensitive methods currently used in Asia). Considering this sensitivity, we suggest that screening programs sample seven colonies per apiary (independent of apiary size) and 312 randomly selected apiaries in a region to be 95% sure of detecting an incipient Tropilaelaps mite invasion. Further analyses counter the currently held view that Tropilaelaps mites prefer drone bee brood cells. Tropilaelaps mite infestation rate was 3.5 +/- 0.9% in drone brood and 5.7 +/- 0.6% in worker brood. We propose the bump test as a standard tool for monitoring of Tropilaelaps mite presence in regions thought to be free from infestation. However, regulators may favor the sensitivity of the Drop test (collecting mites that fall to the bottom of a hive on sticky boards) over the less time-intensive Bump test.

Comparing Apis Mellifera and Bombus spp. Pollination Efficiencies on Willamette Valley Blueberry Farms

With global honeybee populations declining there is a concern for the reproduction of plants that rely on biotic pollination, most notably food crops. The purpose of this study was to monitor the behavior and population size of bumblebees (Bombus spp.) and European honeybees (Apis mellifera) on Highbush Blueberry (Vaccinium corymbosum) farms in the Willamette Valley, Oregon. We evaluated the effects of farm size and bloom time on the pollination efficiency of each species. To make our assessments, we observed their floral handling rates, defined as the number of flowers visited per minute by a single bee, and took population samples, by walking systematically-sampled transects on each farm. Floral handling rate for bumblebees and honeybees was proportional across our two primary variables, with honeybees pollinating an average of 3.5 flowers per minute and bumblebees pollinating 11.2 flowers per minute. Across all farms, honeybees had a total of 1746 counts while bumblebees had only 300, providing a ratio of 5.8:1. Although honeybees were more abundant than bumblebees, there was only an apparent relationship between population counts and bloom time. Data from floral handling rates and abundance counts during mid bloom showed honeybees were three times more abundant than bumblebees, however, bumblebees were more effective pollinators, as measured by bee efficiency rate. Overall, the study indicated the essential role of bumblebees in the pollination of Highbush Blueberry plants.

A survey of pollinator and plant interactions in meadow and grassland habitats of Marin County, California

Abstract. Bees and other pollinators play an essential role in maintaining the plant biodiversity of our planet's landscape through pollination. Few baseline studies or monitoring programs have addressed concerns over local, regional and even worldwide declines in bee populations. We established 22 collection sites in meadow and grassland habitats in Marin County, California to determine which bee genera were present and which plants they were visiting. Some of these habitats were located in National Park Service natural areas and wildlands, including Golden Gate National Recreation Area and Point Reyes National Seashore. During this study we collected a total of 109 bee, wasp and fly specimens and from among these we identified seven genera of bees. The bees were found on 44 species of plants, only 11 of which were native to Marin County. The European honey bee (Apis mellifera), a non-native pollinator, was found on 37 species of plants, 28 of which were non-native.

The breeding biology of the Forest Red-tailed Black Cockatoo Calyptorhynchus banksii naso Gould in south-western Australia. I. Characteristics of nest trees and nest hollows.

The Forest Red-tailed Black Cockatoo Calyptorhynchus banksii naso (FRTBC) is a large, iconic forest cockatoo, endemic to the south-west corner of Western Australia. It is currently listed as Vulnerable under the State Western Australian Wildlife Conservation Act and under the Commonwealth Environment Protection and Biodiversity Conservation Act. In this paper, we provide details of nest tree and nest hollow requirements based on details of hollows in 128 nest trees studied over 17 years. FRTBC are monogamous and pairs nest in tree hollows from 6.5–33 m above ground. Most nests are in very large and very old, mature Marri Corymbia calophylla, a long-lived endemic tree species, which is the most important nesting tree throughout the FRTBC range. Nest trees of all species had a mean circumference at breast height of 2.79 m, a mean estimated age of 222 years and a mean overall height of 20.24 m. Marri nest trees had an mean circumference at breast height of 2.76 m, a mean estimated age of 220 years (95% confidence limit 209–231 years) and an average overall height of 20.04 m. The rate of fall or loss of nest trees was high, c. 16.6% per decade. A wide range of hollow types, defined by position of the hollow in the tree, were found. Hollow aspects were also diverse. The mean height to a hollow was 14.49 m. Mean hollow depth was 1.44 m, mean floor space (the longest linear distance across the bottom of the hollow) was 33.2 cm and the mean hollow entrance area was 30 x 34 cm. FRTBC nests are typically, but not always, clustered in the landscape and social interactions within the flock are likely to play a part in the clustering of nests. Nest competitors, including feral European Honey Bee Apis mellifera, Carnaby’s Cockatoo Calyptorhynchus latirostris, Baudin’s Cockatoo C. baudinii and the Regent Parrot Polytelis anthopeplus were recorded using nest hollows once used by FRTBC. In the past Marri was harvested commercially, especially the largest and oldest trees, for timber and woodchips. In recent times the volume of Marri logs has been reduced due to a decline in markets e.g. between 2004 and 2010 a total of 95,436 m³ was harvested (K. Whitford, pers. comm.). Given the importance of large, old trees for FRTBC breeding habitat, conservation of these trees

Identification of kakusei, a Nuclear Non-Coding RNA, as an Immediate Early Gene from the Honeybee, and Its Application for Neuroethological Study

The honeybee is a social insect that exhibits various social behaviors. To elucidate the neural basis of honeybee behavior, we detected neural activity in freely-moving honeybee workers using an immediate early gene (IEG) that is expressed in a neural activity-dependent manner. In European honeybees (Apis mellifera), we identified a novel nuclear non-coding RNA, termed kakusei, as the first insect IEG, and revealed the neural activity pattern in foragers. In addition, we isolated a homologue of kakusei, termed Acks, from the Japanese honeybee (Apis cerana), and detected active neurons in workers fighting with the giant hornet.