Modelling the impacts of imports of non-native honey bees into the native Apis mellifera mellifera population in Ireland

BackgroundThe Mount Huang eastern honey bees (Apis cerana) are an endemic population, which is well adapted to the local agricultural and ecological environment. In this study, the genetic structure of seven eastern honey bees (A. cerana) populations from Mount Huang in China were analyzed by SSR (simple sequence repeat) markers.ResultsThe results revealed that 16 pairs of primers used amplified a total of 143 alleles. The number of alleles per locus ranged from 6 to 13, with a mean value of 8.94 alleles per locus. Observed and expected heterozygosities showed mean values of 0.446 and 0.831 respectively. UPGMA cluster analysis grouped seven eastern honey bees in three groups.ConclusionThe results obtained show a high genetic diversity in the honey bee populations studied in Mount Huang, and high differentiation among all the populations, suggesting that scarce exchange of honey bee species happened in Mount Huang. Our study demonstrated that the Mount Huang honey bee populations still have a natural genome worth being protected for conservation.Electronic supplementary materialThe online version of this article (doi:10.1186/s41065-016-0010-4) contains supplementary material, which is available to authorized users.

The Western honey bee, Apis mellifera plays a crucial role as a pollinator worldwide. Except the wide number of commercial crops, honey bees pollinate many wild plants, some of which are threatened with extinction and are valuable genetic resource. Although during the last few years honey bee populations are steady and increasing in numbers with some fluctuation, there are a number of threats responsible for honey bee health and survival. As key factors for this are pointing out poor nutrition, sublethal insecticide exposure, and biotic stressors, including diseases and parasites. The decline of honey bee populations negatively affects not only many commercial crop and flowering plants, but also reduces honey bee products such as honey, bee pollen, propolis, bee venom, royal jelly and beeswax etc., many of them with significant role in human health benefits. Many hypotheses have been put forward in an attempt to explain these losses, but so far no indisputable factor has been identified responsible as the main driver of bee decline. Thus, it is necessary to urgently take measures to protect and preserve the honey bee by identifying and neutralizing the most significant causes leading to this phenomenon. Conservation methods are in place to protect A. mellifera and honey bee populations in a large part of the world. However, the survey also reveals the disparity in resources and information dedicated between honey bees and all other pollinators.

Little information is available regarding the adverse effects of pesticides on natural honey bee populations. This study highlights the detrimental effects of pesticides on honey bee olfaction through behavioural studies, scanning electron microscopic imaging of antennal sensillae and confocal microscopic studies of honey bee brains for calcium ions on Apis cerana, a native Indian honey bee species. There was a significant decrease in proboscis extension response and biologically active free calcium ions and adverse changes in antennal sensillae in pesticide exposed field honey bee populations compared to morphometrically similar honey bees sampled from low/no pesticide sites. Controlled laboratory experiments corroborated these findings. This study reports for the first time the changes in antennal sensillae, expression of Calpain 1(an important calcium binding protein) and resting state free calcium in brains of honey bees exposed to pesticide stress.

SummarySamples from seven honey bee populations; five Apis mellifera meda from Iran and two from Turkey, one belonging to A. m. meda and one to A. m. caucasica, were investigated using morphometric, mtDNA, and microsatellite analyses. Morphometric analysis revealed three distinct clusters. The first included all Iranian populations, whilst the second and third contained the meda and caucasica bees from Turkey. No variation was observed in the DraI restriction of COI-COII intergenic region in mitochondrial DNA, yielding a single C lineage mitotype. The analysis of microsatellite loci, A7, A24, A28, A43 and A113 revealed, a considerable level of genetic diversity, with average expected heterozygosity ranging from 0.596±0.188 to 0.695±0.174 and average number of alleles per locus from 4.4 to 8.0 among Iranian honey bee populations.

SummaryPolyacrylamide gel electrophoresis was used to analyse phenoxyethanol extracts from honeybees (Apis mellifera) for malate dehydrogenase activity. Nine natural populations in Kenya consisting of the subspecies Apis mellifera litorea, Apis mellifera nubica, Apis mellifera monticola and Apis mellifera scutellata were sampled. Allozyme variation in the three Mdh alleles found was quite uniform in all the populations. There were small differences among the populations in allele frequencies and in levels of enzyme activity as indicated by intensity of bands. Genetic variation was lower in honeybees than in samples of five Zaprionus species (Diptera, Drosophilidae) taken earlier from the same localities.

SummaryBeekeepers in Europe, North America and other parts of the world have repeatedly been afflicted by elevated and sometimes unexplained colony losses. Multiple factors have been considered in connection with increased winter losses. In addition to national programmes investigating possible causes for increased honey bee mortality, scientists collaborate at an international level on different aspects of bee health within the COLOSS network. Within this network, Working Group 4 explores aspects of genetic diversity in relation to the vitality and health of honey bee populations. In this paper, we briefly review the genetic diversity of honey bees in Europe, discuss the effects of beekeeping and selective breeding on honey bee populations under the aspect of genetic diversity and bee health, and review the current status of EU legislation with respect to protection of native bee populations. We introduce and discuss recent approaches in honey bee selective breeding to improve disease resistance by introducing traits related to colony vitality. Finally, we present the aims of WG4 within the COLOSS network and briefly introduce our experimental approach.

Invasion of alien species has been shown to cause detrimental effects on habitats of native species. Insect pollinators represent such examples; the introduction of commercial bumble bee species for crop pollination has resulted in competition for an ecological niche with native species, genetic disturbance caused by mating with native species, and pathogen spillover to native species. The European honey bee, Apis mellifera, was first introduced into Japan for apiculture in 1877, and queen bees have been imported from several countries for many years. However, its effects on Japanese native honey bee, Apis cerana japonica, have never been addressed. We thus conducted the survey of honey bee viruses and Acarapis mites using both A. mellifera and A. c. japonica colonies to examine their infestation in native and non-native honey bee species in Japan. Honey bee viruses, Deformed wing virus (DWV), Black queen cell virus (BQCV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV), were found in both A. mellifera and A. c. japonica colonies; however, the infection frequency of viruses in A. c. japonica was lower than that in A. mellifera colonies. Based on the phylogenies of DWV, BQCV, and SBV isolates from A. mellifera and A. c. japonica, DWV and BQCV may infect both honey bee species; meanwhile, SBV has a clear species barrier. For the first time in Japan, tracheal mite (Acarapis woodi) was specifically found in the dead honey bees from collapsing A. c. japonica colonies. This paper thus provides further evidence that tracheal-mite-infested honey bee colonies can die during cool winters with no other disease present. These results demonstrate the infestation of native honey bees by parasite and pathogens of non-native honey bees that are traded globally.

Honey bee colonies are large kin groups, each with a single mother queen and thousands of female workers. Queen bees are highly polyandrous, each mating with an average of approximately 12 drones from other colonies. We used a meta-analysis approach to compare the pedigree relationships of honey bee reproductives (queens and their mates) across five different studies and to quantify the overall genetic diversity of breeding populations. We compared the inferred genotypes of queens and their mates from microsatellite analyses of worker offspring from a feral Africanized honey bee population (which served as a negative control for inbreeding), an experimentally derived population of sister queens (which served as a positive control for inbreeding), and three separate commercially managed populations. We then compared the relatedness of all drones mated to each queen (mate-mate), all queens within each population (queen-queen), each queen with each of her mates (queen-mate), and all drones within each population (drone-drone). We found, as expected, the lowest levels of genetic similarity in the outcrossed population and highest levels of genetic similarity in the inbred population. Levels of genetic similarity among the managed honey bee populations were intermediate but closer to that of the inbred population. Genetic structuring of the entire breeding population resulted in two major subpopulations, likely deriving from breeders on the east and west coast. The effects that these findings have on the overall population genetic diversity of managed honey bees is discussed.

Bu calismada Bati Karadeniz Bolgesi ari populasyonu toplam 37 morfolojik karakter yonunden tanimlanmistir. Bolgenin Zonguldak, Sakarya, Bolu, Duzce, Kastamonu ve Sinop illerinden toplam 102 isci ari ornegi degerlendirilmistir. Farkli illerden alinan ornekler arasinda cubital a damar uzunlugu (a), kanat B4 damar acisi, cubital indeks (CI) ve metatarsal indeks (MI) karakterlerince varyasyon belirlenmemistir. Diger 33 morfolojik karakter yonunden onemli varyasyon bulunmustur. Bolgenin yerli arisi icin ayirt edici en onemli morfolojik karakter scutellum rengidir. Bolge icerisinde Zonguldak, Sakarya, Bolu ve Duzce populasyonu digerlerinden daha fazla birbirlerine benzer ve ayri bir kume olusturmuslardir. Duzce yoresi arisi Sakarya ve Bolu arilariyla belirli duzeyde cakismislardir (overlaping). Bolge arilari morfolojik yapi yonunden Anadolu arisi (A. m. anatoliaca) ile bir benzerlik gostermemis ve daha cok Ege ve Gokceada arilarina benzer bulunmustur. MORPHOLOGICAL CHARACTERIZATION OF THE HONEY BEE (Apis mellifera L.) POPULATION OF THE WESTERN BLACK SEA REGION This study was conducted in order to determine and identify the morphological characteristics of the honey bee (Apis mellifera L.) population in the western Black Sea region. A total of 102 experimental worker honey bee samples were collected from Zonguldak, Sakarya, Bolu, Duzce, Kastamonu and Sinop provinces. From each sample, 15 workers were examined and 37 morphological characteristics were measured biometrically. Except length of cubital a vein (a), vein angle B4, cubital index (CI) and metatarsal index (MI), significant (P<0.05, P<0.01 and P<0.001) differences were found between the samples depending on the provinces where bees were located, with respect to other 33 morphological characters. The most discriminative morphological character of the region’s bee population was found to be the colour of scutellum. The worker bee samples of Zonguldak, Sakarya, Bolu and Duzce provinces were likely more resemble to each other than to those of the other provinces, particularly the bees of Duzce overlapped with those of Sakarya and Bolu provinces. It was found that the bees of the western Black Sea region were distant from the Anatolian honey bee subspecies (A. m. anatoliaca) but they were more similar to the honey bee populations of the Aegean region and Gokceada island, in terms of morphology.

Populations of honey bees are declining throughout the world, with US beekeepers losing 30% of their colonies each winter. Though multiple factors are driving these colony losses, it is increasingly clear that viruses play a major role. However, information about the molecular mechanisms mediating antiviral immunity in honey bees is surprisingly limited. Here, we examined the transcriptional and epigenetic (DNA methylation) responses to viral infection in honey bee workers. One-day old worker honey bees were fed solutions containing Israeli Acute Paralysis Virus (IAPV), a virus which causes muscle paralysis and death and has previously been associated with colony loss. Uninfected control and infected, symptomatic bees were collected within 20–24 hours after infection. Worker fat bodies, the primary tissue involved in metabolism, detoxification and immune responses, were collected for analysis. We performed transcriptome- and bisulfite-sequencing of the worker fat bodies to identify genome-wide gene expression and DNA methylation patterns associated with viral infection. There were 753 differentially expressed genes (FDR<0.05) in infected versus control bees, including several genes involved in epigenetic and antiviral pathways. DNA methylation status of 156 genes (FDR<0.1) changed significantly as a result of the infection, including those involved in antiviral responses in humans. There was no significant overlap between the significantly differentially expressed and significantly differentially methylated genes, and indeed, the genomic characteristics of these sets of genes were quite distinct. Our results indicate that honey bees have two distinct molecular pathways, mediated by transcription and methylation, that modulate protein levels and/or function in response to viral infections.

Pollination services are compromised by habitat destruction, land-use intensification, pesticides, and introduced species. How pollination services respond to such stressors depends on the capacity of pollinator assemblages to function in the face of environmental disruption. Here, we quantify how pollination services provided to a native plant change upon removal of the non-native, western honey bee (Apis mellifera)-a numerically dominant floral visitor in the native bee-rich ecosystems of southern California. We focus on services provided to clustered tarweed (Deinandra fasciculata), a native, annual forb that benefits from outcross pollination. Across five different study sites in coastal San Diego County, tarweed flowers attracted 70 insect taxa, approximately half of which were native bees, but non-native honey bees were always the most abundant floral visitor at each site. To test the ability of the native insect fauna to provide pollination services, we performed Apis removals within experimental 0.25m2 plots containing approximately 20 tarweed plants and compared visitation and seed set between plants in removal and paired control plots (n=16 pairs). Even though 92% of observed floral visits to control plots were from honey bees, Apis removal reduced seed production by only 14% relative to plants in control plots. These results indicate that native insect assemblages can contribute important pollination services even in ecosystems numerically dominated by introduced pollinators.

The global spread of the ectoparasitic mite Varroa destructor has promoted the spread and virulence of highly infectious honey bee viruses. This phenomenon is considered the leading cause for the increased number of colony losses experienced by the mite-susceptible European honey bee populations in the Northern hemisphere. Most of the honey bee populations in Central and South America are Africanized honey bees (AHBs), which are considered more resistant to Varroa compared to European honey bees. However, the relationship between Varroa levels and the spread of honey bee viruses in AHBs remains unknown. In this study, we determined Varroa prevalence and infestation levels as well as the prevalence of seven major honey bee viruses in AHBs from three regions of Colombia. We found that although Varroa exhibited high prevalence (92%), its infestation levels were low (4.5%) considering that these populations never received acaricide treatments. We also detected four viruses in the three regions analyzed, but all colonies were asymptomatic, and virus prevalence was considerably lower than those found in other countries with higher rates of mite-associated colony loss (DWV 19.88%, BQCV 17.39%, SBV 23.4%, ABPV 10.56%). Our findings indicate that AHBs possess a natural resistance to Varroa that does not prevent the spread of this parasite among their population, but restrains mite population growth and suppresses the prevalence and pathogenicity of mite-associated viruses.

The parasitic mite, Varroa destructor, in combination with the viruses it vectors, is the main cause for global colony losses of the European honeybee, Apis mellifera. However, an isolated honeybee population established in 1999 on the Island of Gotland, Sweden has naturally acquired resistance to the mite, and has survived without mite control treatment for more than 18 years. A recent study has shown that this mite resistant (MR) population also appears to be resistant to Black queen cell virus (BQCV) and Sacbrood virus (SBV) and tolerant to Deformed wing virus (DWV), relative to nearby mite susceptible (MS) honeybee populations. In this study, RNA sequencing was employed to corroborate these previous findings and identify other viral factors that may play a role in the enhanced survival of this mite resistant honeybee population. Two additional honeybee-infecting viruses, Apis rhabdovirus-1 (ARV-1) and Lake Sinai virus (LSV), were identified and near-complete genomes of these two viruses were obtained. Phylogenetic analyses of the assembled virus sequences revealed consistent separation between the MR and MS honeybee populations, although it is unclear whether this is due to pre-existing differences between the viruses in the two populations when they were established, and isolated, or due to virus genetic adaptation towards reduced virulence in the MR population, to promote colony survival. Reverse transcription quantitative polymerase chain reaction(RT-qPCR) analyses show higher ARV and LSV titres in MS colonies compared to MR colonies, gradually increasing from summer to autumn 2009, and reaching maximum titres in the following spring 2010. While the DWV and BQCV titres in MR colonies increased between autumn 2009 and spring 2010, the SBV practically disappeared entirely by spring 2010. Possible explanations for the apparent virus tolerance or resistance in the Gotland mite-resistant honeybee population are discussed.

Nile tilapia occurs naturally in East Africa where it’s an economically important species. Many of the natural populations of Nile tilapia have been affected by anthropogenic activities including translocations, associated with programmes aimed at enhancing capture fisheries and aquaculture productivity. Using geometric morphometric analyses, we tested the hypothesis that such anthropogenic activities have augmented admixture among natural populations of Nile tilapia and influenced the geographical distribution of morphological variation within the species. Our expectation was that Nile tilapia shape divergent might be consistent with reportedly anthropogenic activities in nonnative environments. To test this hypothesis, we analyzed the shapes of 490 individuals from thirteen populations; three farms, six natives and four nonnative natural populations. Our analysis revealed that the most pronounced shape diversification was observed in seven populations; three nonnatives (Victoria, Kyoga and Sindi farm) and four natives (Albert, River Nile, George and Turkana). The features responsible for the observed morphotypes were mainly related to the orientation of the anterior region of the fish and may be due to diversifying selection in response to new environmental pressures (for nonnative populations), admixture or drift. Shape change in the nonnative high-altitude populations was unexpectedly conserved, suggesting recent introductions which may have not resulted in admixture or there was strong selection against change in the traits measured. On the other hand, the recorded morphotypic clusters explained the possible genetic link to their putative ancestral home. Our results were partially consistent with our prediction that the nonnative populations exhibited divergent morphotypes. We recommend further investigations with molecular genetics for follow-up of these findings.

The Africanization of honey bees (Apis mellifera L.) in the Americas is among the most extensive insect invasions in the world, with large-scale effects on the economy and ecology of a whole continent. Africanized honey bees (AHBs) are a distinctive lineage of A. mellifera, resulting of the extensive admixture between African subspecies (A. m. scutellata and A.m. adansoni) with resident European stocks of honey bees introduced into the Americas. Despite its great importance, to date, the outcome of Africanization of honey bees has not been evaluated in detail. In this article we use the case of Mexico, one of the top beekeeping countries in the world, to assess the effects of Africanization of honey bees and its outcome. There is evidence of African genes in honey bee populations across Mexico, with prevalence in the tropical areas and less so in temperate ones. The Africanization of honey bees resulted in lower honey yields per hive in temperate climates of Mexico, but this has not been assessed in the tropical regions. Mexico’s total honey production and exports at the start of the Africanization process decreased, but today, they have partially rebounded and have remained stable. As in all countries where Africanization has occurred, the defensive behavior of honey bees in Mexico increased but notably, stinging incidents involving humans have been relatively insignificant (0.23 fatalities per million people). Ecologically, AHBs seem to have posed limited impact on the native apifauna and have contributed to pollination of major economic crops, but more studies are needed to evaluate the overall effect. AHBs can be potentially more resistant to parasites and diseases and worth of note is that AHBs in Mexico resulted in a new generation of beekeepers that propelled management and selective breeding. In general, the evidence suggests that the Africanization of honey bees in Mexico has had a less severe impact than originally predicted. We suggest some lines for future directions that may help to better understand the effects, make sustainable use and ameliorate the negative characteristics of AHBs.