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Stingless bees are a diverse group of insects that contribute a wealth of fauna to Central America, as well as being important pollinators. Colonies of these stingless bees are managed and transported unregulated across geographic regions on the basis that they are native species. Populations of Nannotrigona perilampoides, one of the most common stingless bee species in Mexico and Central America, are separated by several geographical barriers that may act as obstacles to gene flow. In addition, their biological and reproductive characteristics make them susceptible to variation among their populations. In this work, we combined morphometric and molecular analyses (through cox1, 16S, ITS1 and ITS2 sequencing) to test whether there is a differentiation between distant populations of N. perilampoides separated by the Sierra Madre Mountain complex. Analyses of wing geometric morphometrics and sequence variation of a fragment of the 16S gene revealed significant differences between populations. These differences show a pattern of isolation by distance, and the possible effect of the Sierra Madre as a biogeographical barrier. The results suggest that N. perilampoides may be composed of distinct evolutionary units and that colony exchange among regions should be restricted to preserve the diversity of this species.

Novel transmission routes can allow infectious diseases to spread, often with devastating consequences. Ectoparasitic varroa mites vector a diversity of RNA viruses and, having switched hosts from the eastern to western honey bees (Apis ceranatoApis mellifera). They provide an opportunity to explore how novel transmission routes shape disease epidemiology. As the principal driver of the spread of Deformed Wing Viruses (mainly DWV-A and DWV-B), varroa infestation has also driven global honey bee health declines. The more virulent DWV-B strain has been replacing the original DWV-A strain in many regions over the past two decades. Yet, how these viruses originated and spread remains poorly understood. Here we use a phylogeographic analysis based on whole genome data to reconstruct the origins and demography of DWV spread. We found that, rather than reemerging in western honey bees after varroa switched hosts, as suggested by previous work, DWV-A most likely originated in Asia and spread in the mid-20thcentury. It also showed a massive population size expansion following the varroa host switch. By contrast, DWV-B was most likely acquired more recently from a source outside Asia, and appears absent from eastern honey bees, the original varroa host. These results highlight the dynamic nature of viral adaptation, whereby a vector’s host switch can give rise to competing and increasingly virulent disease pandemics. The evolutionary novelty and rapid global spread of these host-virus interactions, together with observed spillover into other species, illustrate how increasing globalisation poses urgent threats to biodiversity and food security.

Insect pollination is crucial for the maintenance of natural and managed ecosystems but the functioning of this ecosystem service is threatened by a worldwide decline of pollinators. Key factors in this situation include the spread and interspecific transmission of pathogens worldwide through the movement of managed pollinators. Research on this field has been mainly conducted in some particular species, while studies assessing the interspecific transmission of pathogens at a community level are scarce. However, this information is pivotal to design strategies to protect pollinators. Herein, we analysed the prevalence of two common microsporidia pathogens of managed honey bees (Nosema ceranae and N. apis) in bee communities of semiarid Mediterranean areas from the Southeast of the Iberian Peninsula. Our results confirm the ability of N. ceranae to disperse across wild bee communities in semiarid Mediterranean ecosystems since it was detected in 36 Apoidea species (39% of the sampling; for the first time in nine genera). The prevalence of the pathogen did not show any phylogenetic signal which suggests a superfamily host range of the pathogen or that wild bees may be acting only as vectors of N. ceranae. In addition, N. apis was detected in an Eucera species, which is the second time it has been detected by molecular techniques in a host other than the honey bee. Our study represents the primary assessment of the prevalence of microsporidia at community level in Mediterranean areas and provides outstanding results on the ability of Nosema pathogens to spread across the landscape.

Diploid males represent a cost for the viability of populations in haplodiploid species with a single-locus complementary sex determination system. In such social species as bumble bees, their pres...

International audience; To provide a complete portrayal of the multiple factors negatively impacting insects in agricultural landscapes it is necessary to assess the concurrent incidence, magnitude, and interactions among multiple stressors over substantial biogeographical scales. Trans-national ecological field investigations with wide-ranging stakeholders typically encounter numerous challenges during the design planning stages, not least that the scientific soundness of a spatially replicated study design must account for the substantial geographic and climatic variation among distant sites. ‘PoshBee’ (Pan-European assessment, monitoring, and mitigation of Stressors on the Health of Bees) is a multi-partner transdisciplinary agroecological project established to investigate the suite of stressors typically encountered by pollinating insects in European agricultural landscapes. To do this, PoshBee established a network of 128 study sites across eight European countries and collected over 50 measurements and samples relating to the nutritional, toxicological, pathogenic, and landscape components of the bees’ environment. This paper describes the development process, rationale, and end-result of each aspect of the of the PoshBee field investigation. We describe the main issues and challenges encountered during the design stages and highlight a number of actions or processes that may benefit other multi-partner research consortia planning similar large-scale studies. It was soon identified that in a multi-component study design process, the development of interaction and communication networks involving all collaborators and stakeholders requires considerable time and resources. It was also necessary at each planning stage to be mindful of the needs and objectives of all stakeholders and partners, and further challenges inevitably arose when practical limitations, such as time restrictions and labour constraints, were superimposed upon prototype study designs. To promote clarity for all stakeholders, for each sub-component of the study, there should be a clear record of the rationale and reasoning that outlines how the final design transpired, what compromises were made, and how the requirements of different stakeholders were accomplished. Ultimately, multi-national agroecological field studies such as PoshBee benefit greatly from the involvement of diverse stakeholders and partners, ranging from field ecologists, project managers, policy legislators, mathematical modelers, and farmer organisations. While the execution of the study highlighted the advantages and benefits of large-scale transdisciplinary projects, the long planning period emphasized the need to formally describe a design framework that could facilitate the design process of future multi-partner collaborations.

Managed honey bees have suffered severe seasonal losses for most of the past 30 years, while at the same time there is a growing need for food crop pollination. Parasitism by Varroa destructor plays a key role in explaining these losses as this parasite directly damages honey bees by feeding on them and by vectoring an array of viruses while doing so. Pyrethroids like tau-fluvalinate and flumethrin are among the few acaricides that may control Varroa mites in honey bee colonies. However, their intensive use has led to the evolution of resistance in many locations. Knockdown resistance (kdr-type) in Varroa destructor is associated with point mutations that change the amino acid at position 925 in the para-type voltage-gated sodium channel (VGSC) from leucine to valine, methionine or isoleucine. In order to assess the evolution of resistant mutations, we genotyped a region of the VGSC from V. destructor samples collected worldwide. Our phylogenetic analysis supports the hypothesis of independent origin for resistant alleles in Europe and the USA, and a close relation between L925M and L925I alleles. Our data also suggest that uncontrolled trading of parasitised honey bees might be an important route for spreading resistant alleles overseas. The substitution M918L, associated with pyrethroid resistance in other species, is reported here for the first time in V. destructor, in conjunction with L925V in mites from Spain. The implications of these evolutionary and dispersal processes for Varroa mite management are discussed.

Assessing the extent of parasite diversity requires the application of appropriate molecular tools, especially given the growing evidence of multiple parasite co-occurrence. Here, we compared the performance of a next-generation sequencing technology (Ion PGM ™ System) in 12 Bombus terrestris specimens that were PCR-identified as positive for trypanosomatids (Leishmaniinae) in a previous study. These bumblebees were also screened for the occurrence of Nosematidae and Neogregarinorida parasites using both classical protocols (either specific PCR amplification or amplification with broad-range primers plus Sanger sequencing) and Ion PGM sequencing. The latter revealed higher parasite diversity within individuals, especially among Leishmaniinae (which were present as a combination of Lotmaria passim, Crithidia mellificae and Crithidia bombi), and the occurrence of taxa never reported in these hosts: Crithidia acanthocephali and a novel neogregarinorida species. Furthermore, the complementary results produced by the different sets of primers highlighted the convenience of using multiple markers to minimize the chance of some target organisms going unnoticed. Altogether, the deep sequencing methodology offered a more comprehensive way to investigate parasite diversity than the usual identification methods and provided new insights whose importance for bumblebee health should be further analysed.

International audience; The genetic diversity of the honey bee (Apis mellifera) remains undescribed in some parts of its natural distribution range, concretely in those subspecies inhabiting central and southeastern Europe: the globally distributed A. m. ligustica and A. m. carnica, and A. m. cecropia and A. m. macedonica. In this study, we add further information about their genetic variation, differentiation, and admixture using maternal and codominant (microsatellites) molecular markers. The phylogeographic analysis demonstrated the distinct distribution of mitochondrial haplotypes across the sampled geographic range. Cluster analysis detected two main groups of colonies while further discriminant analysis of the principal components supported the existence of ecotypes within A. m carnica and A. m. macedonica, and admixture of them. The extent of introgression and the presence of foreign haplotypes in some of these populations suggested that introductions of non-native subspecies represent a serious threat to the genetic integrity of native honey bee populations due to the creation of hybrid populations.

Trypanosomatids are among the most prevalent parasites in bees but, despite the fact that their impact on the colonies can be quite important and that their infectivity may potentially depend on their genotypes, little is known about the population diversity of these pathogens. Here we cloned and sequenced three non-repetitive single copy loci (DNA topoisomerase II, glyceraldehyde-3-phosphate dehydrogenase and RNA polymerase II large subunit, RPB1) to produce new genetic data from Crithidia bombi, C. mellificae and Lotmaria passim isolated from honeybees and bumblebees. These were analysed by applying population genetic tools in order to quantify and compare their variability within and between species, and to obtain information on their demography and population structure. The general pattern for the three species was that (1) they were subject to the action of purifying selection on nonsynonymous variants, (2) the levels of within species diversity were similar irrespective of the host, (3) there was evidence of recombination among haplotypes and (4) they showed no haplotype structuring according to the host. C. bombi exhibited the lowest levels of synonymous variation (πS= 0.06 ± 0.04 %) — and a mutation frequency distribution compatible with a population expansion after a bottleneck — that contrasted with the extensive polymorphism displayed by C. mellificae (πS= 2.24 ± 1.00 %), which likely has a more ancient origin. L. passim showed intermediate values (πS= 0.40 ± 0.28 %) and an excess of variants a low frequencies probably linked to the spread of this species to new geographical areas.

In this study, we update the knowledge about wild bees of the genus Hylaeus in the Canary Islands and discuss the possible effect on the phenology of exotic species on the endemic ones. Our records come both from entomological samplings and citizen science through photos registered in social networks. An additional molecular approach was performed to confirm correct identification and analyze their geographic origin. Two new exotic species, Hylaeus (Paraprosopis) pictipes Nylander, 1852 in Tenerife and Hylaeus (Spatulariella) punctatus (Brullé, 1832) in Tenerife and Gran Canaria have been detected. In addition, we provide new records of Hylaeus (Spatulariella) sulphuripes (Gribodo, 1894) in Tenerife and Gran Canaria. All three species show a flight season extending from late spring to early winter. Most observations were made in anthropized areas, visiting both native and exotic plants. Exotic species were localized on the larger islands of the archipelago where maritime traffic is higher, being the most likely route of entry. Molecular data suggest two independent arrivals of H. pictipes to Tenerife from the Iberian Peninsula, while H. puntactus would have arrived from central Europe. There is little overlap with the phenology and habitat of the endemic species, so there does not seem to be a potentially significant negative effect on them.

Migratory beekeeping is a widely extended practice aimed at increasing the yield of products and pollination services of honey bee colonies. However, it represents a stress factor, as it facilitates the dissemination of diseases and may compromise the genetic identity of the colonies involved. To analyze the extent of these effects, pathogens infestation rate and genetic composition were monitored in a field experiment comparing stationary and migratory colonies sharing the same environmental conditions but differing in management (stationary vs. migratory) and genetic background. We studied the pathogens infestation rate (Varroa destructor, Nosema spp., and Deformed Wing Virus (DWV)) at four different times: before migratory operation, two weeks later, at the end of the migratory period, and two weeks after the return of the migratory hives. An increased incidence of V. destructor and Nosema ceranae and a lower DWV viral load were found in migratory colonies. Temporary changes in genetic diversity were detected regardless of colony type, suggesting that stressors other than management affect the genetic diversity of the colonies. Our study demonstrates that migratory practices have variable effects on the health and genetic diversity of honey bee colonies, which should be taken into account for the development of sustainable beekeeping.

The bumblebee Bombus terrestris is used worldwide for crop pollination. Despite its positive impact on crop yield, it has become a widespread threat to biodiversity due to its interactions with local bumblebee populations. Commercial subspecies introduced to the Iberian Peninsula since the 1990s without any regulation have colonized the environment, with evidence of naturalization and introgression with the endemic subspecies Bombus terrestris lusitanicus. We have used mitochondrial and nuclear genetic data to describe the current genetic diversity of the Iberian population and to estimate the expansion of commercial bumblebees. Samples from the natural distribution range of the commercial subspecies, the natural intergradation area between the two subspecies and from a period prior to the use of commercial colonies (i.e., before the 1990s) have been used for comparison. Our results show that the mitochondrial haplotype of the commercial breeds has spread throughout the territory, which, together with subtle changes observed in the nuclear genetic diversity of the populations, indicates that hybridization and consequent introgression are occurring in most of the peninsula. It is, therefore, necessary to improve the existing legislation concerning the management and exportation of commercial bumblebees to conserve locally adapted populations.

Sicily (Italy) is an important hotspot diversity for bees and new species records are constantly reported for the island. Here, we rediscovered after 45 years without records, the occurrence in Eas...

The taxonomic status of Bombus terrestris subspecies is complex and has deep implications in the management of commercial bumblebees for crop pollination as well as in the establishment of appropriate conservation plans. Herein, the complete mitogenome of the endemic Canary Islands subspecies Bombus terrestris canariensis is newly sequenced and compared with available mitochondrial sequences in order to shed light into its taxonomic status. The mitochondrial genome was 17,300 bp in length and contained 37 genes, including 13 protein-coding genes (PCGs), two rRNAs, and 22 tRNAs and a partial sequence of the AT rich control region. The phylogenetic analysis of PCGs of the mitogenome was congruent with its subspecific status and a close relationship with the North African subspecies africanus as previously suggested. The sequencing of the mitogenome of B. t. canariensis provides useful genetic information to study the conservation genetics and genetic diversity of these island bumblebee populations.

The Iberian Peninsula is known to have acted as a glacial refugium for many species during the Pleistocene in Europe. Several phylogeographical studies have been carried out within the genus Bombus which indicate a genetic differentiation of some of its species in the southern European peninsulas. Bombus lucorum (Linnaeus, 1761) is one of the three cryptic species belonging to the B. lucorum complex. In recent years, this complex has been widely studied; however, there is a lack of information about the genetic diversity of this species and its possible postglacial recolonization events. To overcome this knowledge gap, in this study several populations from the centre of the Iberian Peninsula to Belgium have been characterized using mitochondrial and nuclear markers (cox1 barcoding and 11 microsatellite loci) and the geometric morphometrics of the wings. Results from cox1 indicate a genetic differentiation of the population of Sierra de Guadarrama at the centre of the Iberian Peninsula, while microsatellite loci and geometric morphometrics analyses do not show any population structure. These results point to a past event of genetic differentiation of B. lucorum in the Iberian Peninsula although they also suggest a current gene flow with populations from mainland Europe.

Background With numerous endemic subspecies representing four of its five evolutionary lineages, Europe holds a large fraction of Apis mellifera genetic diversity. This diversity and the natural distribution range have been altered by anthropogenic factors. The conservation of this natural heritage relies on the availability of accurate tools for subspecies diagnosis. Based on pool-sequence data from 2145 worker bees representing 22 populations sampled across Europe, we employed two highly discriminative approaches (PCA and F-ST) to select the most informative SNPs for ancestry inference. Results Using a supervised machine learning (ML) approach and a set of 3896 genotyped individuals, we could show that the 4094 selected single nucleotide polymorphisms (SNPs) provide an accurate prediction of ancestry inference in European honey bees. The best ML model was Linear Support Vector Classifier (Linear SVC) which correctly assigned most individuals to one of the 14 subspecies or different genetic origins with a mean accuracy of 96.2% +/- 0.8 SD. A total of 3.8% of test individuals were misclassified, most probably due to limited differentiation between the subspecies caused by close geographical proximity, or human interference of genetic integrity of reference subspecies, or a combination thereof. Conclusions The diagnostic tool presented here will contribute to a sustainable conservation and support breeding activities in order to preserve the genetic heritage of European honey bees. European CommissionEuropean CommissionEuropean Commission Joint Research Centre [2013.1.3-02, 613960]; Basque GovernmentBasque Government [IT1233-19] The SmartBees project was funded by the European Commission under its FP7 KBBE programme (2013.1.3-02, SmartBees Grant Agreement number 613960) https://ec.europa.eu/research/fp7.MP was supported by a Basque Government grant (IT1233-19). The funders provided the financial support to the research, but had no role in the design of the study, analysis, interpretations of data and in writing the manuscript. WOS:000614429400001 2-s2.0-85100413967 PubMed: 33535965

Island ecosystems are particularly vulnerable to the introduction of exotic species that can have an impact on local fauna and flora. Here, the carpenter bee Xylocopa pubescens is reported in Gran Canaria (Canary Islands, Spain) for the first time. This species is native to North Africa and the Near East and shows a rapid dispersion across the city of Las Palmas de Gran Canaria, together with a single record in the southernmost tip of the island. Different hypotheses about its arrival to the island are discussed., P. De la Rúa is supported by Project 19908/GERM/2015 of Regional Excellence (Fundación Séneca).

Insect pollination is crucial for the maintenance of natural and managed ecosystems but the functioning of this ecosystem service is threatened by a worldwide decline of pollinators. Key factors in this situation include the spread and interspecific transmission of pathogens worldwide through the movement of managed pollinators. Research on this field has been mainly conducted in some particular species, while studies assessing the interspecific transmission of pathogens at a community level are scarce. However, this information is pivotal to design strategies to protect pollinators. Herein, we analysed the prevalence of two common microsporidia pathogens of managed honey bees (Nosema ceranae and N. apis) in bee communities of semiarid Mediterranean areas from the Southeast of the Iberian Peninsula. Our results confirm the ability of N. ceranae to disperse across wild bee communities in semiarid Mediterranean ecosystems since it was detected in 36 Apoidea species (39% of the sampling; for the first time in nine genera). The prevalence of the pathogen did not show any phylogenetic signal which suggests a superfamily host range of the pathogen or that wild bees may be acting only as vectors of N. ceranae. In addition, N. apis was detected in an Eucera species, which is the second time it has been detected by molecular techniques in a host other than the honey bee. Our study represents the primary assessment of the prevalence of microsporidia at community level in Mediterranean areas and provides outstanding results on the ability of Nosema pathogens to spread across the landscape.

Long-distance dispersal (LDD) is a pivotal process for plants determining their range of distribution and promoting gene flow among distant populations. Most fleshy-fruited species rely on frugivorous vertebrates to disperse their seeds across the landscape. While LDD events are difficult to record, a few ecological studies have shown that birds move a sizeable number of ingested seeds across geographic barriers, such as sea straits. The foraging movements of migrant frugivores across distant populations, including those separated by geographic barriers, creates a constant flow of propagules that in turn shapes the spatial distributions of the genetic variation in populations. Here, we have analysed the genetic diversity and structure of 74 populations of Pistacia lentiscus, a fleshy-fruited shrub widely distributed in the Mediterranean Basin, to elucidate whether the Mediterranean Sea acts as a geographic barrier or alternatively whether migratory frugivorous birds promote gene flow among populations located on both sides of the sea. Our results show reduced genetic distances among populations, including intercontinental populations, and they show a significant genetic structure across an eastern-western axis. These findings are consistent with known bird migratory routes that connect the European and African continents following a north-southwards direction during the fruiting season of many fleshy-fruited plants. Further, approximate Bayesian analysis failed to explain the observed patterns as a result of historical population migrations at the end of Last Glacial Maximum. Therefore, anthropic and/or climatic changes that would disrupt the migratory routes of frugivorous birds might have genetic consequences for the plant species they feed upon.

Montero-Castano, A., Calvino-Cancela, M., Rojas-Nossa, S., De la Rua, P., Arbetman, M., Morales, C.L. 2018. Biological invasions and pollinator decline. Ecosistemas 27(2): 42-51. Doi.: 10.7818/ECOS.1319 Biological invasions are among the main threats to biodiversity, and pollinators are not exempt from such threat.Here, we review the mechanisms through which animal and plant invasive species may affect pollinators, either directly or indirectly. We classified these mechanisms in four groups: (a) changes in habitat quantity or quality, (b) predation, (c) pathogen spread and (d) genetic introgression. We review the impacts of these mechanisms on the behaviour, demography and evolution of native pollinators and their communities. In addition, we highlight some current knowledge gaps about the effect of biological invasions on pollinators and suggest some measures to minimize such effects.

Trypanosomatids are highly prevalent pathogens of Hymenoptera; however, most molecular methods used to detect them in Apis and Bombus spp. do not allow the identification of the infecting species, which then becomes expensive and time consuming. To overcome this drawback, we developed a multiplex PCR protocol to readily identify in a single reaction the main trypanosomatids present in these hymenopterans (Lotmaria passim, Crithidia mellificae and Crithidia bombi), which will facilitate the study of their epidemiology and transmission dynamics. A battery of primers, designed to simultaneously amplify fragments of the RNA polymerase II large subunit (RPB1) of L. passim, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of C. mellificae and the DNA topoisomerase II (TOPII) of C. bombi, was tested for target specificity under single and mixed template conditions using DNA extracted from cell cultures (L. passim ATCC PRA403; C. mellificae ATCC 30254) and from a bumblebee specimen infected with C. bombi only (14_349). Once validated, the performance of the method was assessed using DNA extractions from seven Apis mellifera (Linnaeus, 1758) and five Bombus terrestris (Linnaeus, 1758) field samples infected with trypanosomatids whose identity had been previously determined by PCR-cloning and sequencing (P-C-S). The new method confirmed the results obtained by P-C-S: two of the honeybee samples were parasitized by L. passim, C. mellificae and C. bombi at the same time, whereas the other five were infected with L. passim only. The method confirmed the simultaneous presence of L. passim and C. mellificae in two B. terrestris, where these parasites had not previously been reported.

Urbanization threatens biodiversity worldwide and is expected to increase in the future. This involves intensification of fragmentation and increase of urban forest remnants. Thus, it is important to understand the functioning of these patches for the preservation of local biodiversity. Mutualistic interactions such as seed dispersal have a key role in the dynamics of plant populations and could help to mitigate the negative effects of fragmentation on wild plant populations. In this context, we have used the mastic Pistacia lentiscus, a common Mediterranean shrub, as a model to study the interaction between seed dispersal by birds and the local genetic diversity of individuals in a highly fragmented semiarid forestry area of the Iberian Southeast (Murcia, Spain). Results reveal a high genetic diversity and a lack of differentiation between shrub patches of P. lentiscus in the area, probably as a result of a strong, but rather recent fragmentation, and an apparently poor contribution of birds to the dispersal of Pistacia seeds. However, the existence of latent impacts cannot be discarded, since at least one of the patches shows some signs of inbreeding.

Pathogens are major suspects for the current massive losses of honey bee colonies worldwide. Information about circulation and modes of transmission of Nosema ceranae, an emergent microsporidium parasite of Apis mellifera, is currently lacking. Here we examine the dispersion of N. ceranae and N. apis by the blue-tailed bee-eater Merops philippinus, a migratory bird whose distribution along Southeast Asia overlaps with the original distribution of N. ceranae. We investigate the presence of Nosema spp. spores in bee-eater pellets, feces and nest material collected on the isolated Kinmen island (Taiwan). We found N. ceranae in all types of samples, whilst N. apis was not detected. We describe for the first time the occurrence of N. ceranae spores in birds’ feces, which increases the potential of this bird species as a dispersive agent of the parasite. We molecularly assessed the occurrence of A. cerana and A. mellifera remains in infected and non-infected samples. We discuss the low prevalence of N. ceranae ...

International audience; AbstractThe stingless bee Melipona beecheii is extensively distributed across Mexico and Central America and the only Melipona found in the Greater Antilles. The aim of this work was to establish possible continental affinities of M. beecheii from the Antilles. We compared populations from the main island (Cuba) with two clearly separated genetic lineages of M. beecheii on mainland, namely the Yucatán peninsula (Mexico) and Costa Rica. We used morphometrics, the degree of cephalic maculation, and microsatellite variation. Results indicate a greater morphological and genetic similarity between populations from Cuba and the Yucatán peninsula with respect to those of Costa Rica. Based on our findings, we conclude that the origin of M. beecheii from Cuba is more likely the Yucatán peninsula (Mexico). We found evidence that isolation has not been large enough to result in a new genetic lineage.

The influence of genetic diversity and exposure to xenobiotics on the prevalence of pathogens was studied within the context of a voluntary epidemiological study in Spanish apiaries of Apis mellifera iberiensis, carried out during the spring season of years 2014 and 2015. As such, the evolutionary lineages of the honey bee colonies were identified, a multiresidue analysis of xenobiotics was carried out in beebread and worker bee samples, and the Toxic Unit (TUm) was estimated for each sampled apiary. The relationship between lineages and the most prevalent pathogens (Nosema ceranae, Varroa destructor, trypanosomatids, Black Queen Cell Virus; and Deformed Wing Virus) was analysed with contingency tables, and the possible relationships between TUm and the prevalence of these pathogens were studied by using a factor analysis. The statistical analysis supported the associations between V. destructor and Deformed Wing Virus (DWV), and between N. ceranae and Black Queen Cell Virus (BQCV), but the association between these pathogens and trypanosomatids was not observed. TUm values varied between 5.5 × 10−6 and 3.65 × 10−1. When TUm 10% in the 63% of the cases. The prevalence of pathogens did not appear to be influenced by the distribution of evolutionary lineages and, while the prevalence of V. destructor was not found to be determined by TUm, there was a trend towards an increasing prevalence of N. ceranae when TUm ≥ 23 10−4. This study is an example of using TUm approach beyond the field of the ecotoxicology.

The aim of this study was to investigate the genetic diversity of Varroa destructor parasitizing Apis mellifera colonies and to test for possible host-parasite association at the mitochondrial DNA (mtDNA) level. Six A. mellifera haplotypes (including a novel C2aa) and five haplotypes of V. destructor were detected in 29 analyzed colonies from eight sampling sites in Serbia. We revealed the presence of the K and S1 haplotypes as well as KS1 and KP1 heteroplasmic mite individuals in all localities, while the P1 haplotype was only found in four sampling sites. Significant differences in V. destructor genetic diversity were found at both apiary and colony levels, with mite haplotypes coexisting in almost all tested colonies. In addition, a significant correlation between the number of analyzed mites per colony and the number of identified V. destructor haplotypes was observed. However, no significant host-parasite relationship was found, suggesting that mites bearing different haplotypes as well as those heteroplasmic individuals are well adapted to the host, A. mellifera, independently of the identified haplotype present in each colony. Our results will contribute to future population and biogeographic studies concerning V. destructor infesting A. mellifera, as well as to better understanding their host-parasite relationship.

Across the globe, wild bees are threatened by ongoing natural habitat loss, risking the maintenance of plant biodiversity and agricultural production. Despite the ecological and economic importance of wild bees and the fact that several species are now managed for pollination services worldwide, little is known about how land use and beekeeping practices jointly influence gene flow. Using stingless bees as a model system, containing wild and managed species that are presumed to be particularly susceptible to habitat degradation, here we examine the main drivers of tropical bee gene flow. We employ a novel landscape genetic approach to analyse data from 135 populations of 17 stingless bee species distributed across diverse tropical biomes within the Americas. Our work has important methodological implications, as we illustrate how a maximum-likelihood approach can be applied in a meta-analysis framework to account for multiple factors, and weight estimates by sample size. In contrast to previously held beliefs, gene flow was not related to body size or deforestation, and isolation by geographic distance (IBD) was significantly affected by management, with managed species exhibiting a weaker IBD than wild ones. Our study thus reveals the critical importance of beekeeping practices in shaping the patterns of genetic differentiation across bee species. Additionally, our results show that many stingless bee species maintain high gene flow across heterogeneous landscapes. We suggest that future efforts to preserve wild tropical bees should focus on regulating beekeeping practices to maintain natural gene flow and enhancing pollinator-friendly habitats, prioritizing species showing a limited dispersal ability.

Geometric morphometrics and molecular methods are effective tools to study the variability of stingless bee populations and species that merit protection given their worldwide decline. Based on previous evidence of cryptic lineages within the Scaptotrigona genus, we tested the existence of multiple evolutionary lineages within the species S. mexicana and we investigated the status of S. pectoralis. By analyzing their population structure, we found differences between the Pacific and Atlantic populations of each of these species, although geometric morphometrics of the wing only confirmed these results in S. mexicana. There was a tendency towards enhanced genetic differentiation over larger distances in the Atlantic populations of both species but not in the Pacific populations. These results revealed a pattern of differentiation among evolutionary units and a specific distribution of genetic diversity within these Scaptotrigona species in Mesoamerica, suggesting the need for future taxonomic revisions, as well as activities aimed at management and conservation.

Bumblebees (genus Bombus Latreille) are pollinator insects of great ecological and economic importance, which commercial use for pollination has increased since the 80s. However, the introduction of foreign Bombus terrestris (Linnaeus) has resulted in a decline of native bumblebee populations in Japan, Chile or Argentina among others. To study the potential introgression of commercial B. terrestris into the Iberian endemic subspecies Bombus terrestris lusitanicus Kruger, it is necessary to find a precise molecular marker that differentiates both subspecies. For this purpose, comparative analyses were carried out between B. t. lusitanicus and B. t. terrestris (Linnaeus) from Spain and from Belgium by sequencing the nuclear genes elongation factor 1-α and arginine kinase and the mitochondrial gene 16S ribosomal RNA, and genotyping with eleven microsatellite loci . No differentiation was observed at the nuclear level, but haplotypes found within the 16S sequence correlated with the morphological characterization of the subspecies. In a case study including individuals sampled before the establishment of bumblebee rearing companies and others from recent samplings, we detected hybrid individuals (those with non-matching morphological subspecies and 16S haplotype) more frequently in the south supporting the naturalization of commercial B. t. terrestris and introgression events between both subspecies. This marker should be used in Iberian populations with the aim to support management and conservation actions in endemic populations of B. t. lusitanicus .

Los abejorros (género Bombus Latreille 1802) son insectos polinizadores clave de gran importancia tanto ecológica como económica. Una de las posibles causas de su declive a nivel mundial es la competencia con formas no nativas, introducidas para polinizar cultivos de invernadero. El propósito de este trabajo es encontrar un marcador molecular que permita diferenciar la subespecie endémica de la península Ibérica Bombus terrestris lusitanicus Krüger, 1956 de la subespecie introducida Bombus terrestris terrestris Linnaeus, 1758, diferenciables por su coloración. Se han comparado individuos de B. t. lusitanicus procedentes de España (nativos) y de B. t. terrestris de Bélgica (introducidos). Se han secuenciado fragmentos de ADN nuclear (factor de elongación 1-α, arginina kinasa, ITS-1) y de ADN mitocondrial (16S). Además se analizó la variabilidad de once loci de microsatélites y de ciertos datos de morfometría geométrica. Únicamente la información obtenida del análisis de la morfometría geométrica permitieron diferenciar a los individuos según su subespecie. Se discute, por tanto, si el concepto de subespecie es correcto, desde una definición molecular, para separar B. t. lusitanicus y B. t. terrestris, al ser diferenciables únicamente por su morfología y distribución natural.

International audience; AbstractA nationwide survey was performed to study the distribution of parasites, pathogens and pesticides in managed honey bee populations in Ghana. When 45 colonies were sampled and inspected for signs of disease, Varroa destructor was the most prevalent parasite (89%; n = 40), all mites corresponding to the Korean haplotype of this pathogen. Aethina tumida (42%; n = 19) and Braula coeca (7%; n = 3) were also detected, as were Melissococcus plutonius and trypanosomatids (7%). By contrast, Nosema spp., Acarapis spp., Ascosphaera apis and Paenibacillus larvae were not detected by molecular screening. Amitraz was the most widely distributed pesticide (75%; n = 23) followed by coumaphos (47%; n = 15), chlorpyrifos (34%; n = 15) and fluvalinate (31%; n = 10). This survey lays the groundwork for further monitoring of honey bee populations in Ghana.

The Pyrenees, where Euro-Siberian, Mediterranean and alpine faunas join together, have a large biodiversity of bumblebees. We compiled historical literature records of bumblebee species from the Spanish Pyrenees, and then compared these to contemporary surveys to assess trends in elevational distribution. Twenty-eight species (including thirty-five subspecies) were found in the contemporary survey. Nine species and two subspecies previously present were not detected, some included on the Spanish Red List. With the exception of a few species, a reduction of the altitudinal range and an orophilous tendency was observed at both upper and lower elevational levels, suggesting an upward trend towards better-preserved high areas. Our results reinforce the need to develop new protection programs and more restrictive conservation measures for bumblebee populations, species and their habitats.

Apis mellifera siciliana is a honey bee subspecies prone to be conserved. Conservation measures include maintaining colonies on different islands to serve as parental lines for outcrossing. Molecular diversity and genetic structure of honey bees from Sicily (main island) and Vulcano and Filicudi (conservation islands) were analysed with mitochondrial and microsatellite markers to assess the efficacy of the ongoing conservation effort. Samples from continental Italy and Sardinia island were included for comparison. All the samples of the conservation islands were included in the African (A) evolutionary lineage, while western and northern (M) and eastern (C) European evolutionary lineages were also detected in colonies from the main island (17.1% and 22% respectively), thus highlighting introgression at the mitochondrial level. Nuclear data from conservation and main island populations were compared to evaluate the proportion of admixed honey bees. A higher level of hybridization was found in the central and eastern areas of Sicily main island. Our data describe the efficacy of the conservation islands, and suggest where and how to manage mating stations to further improve the present conservation strategy by recovering additional residual genetic variability of A. m. siciliana. We also propose the establishment of a European network of conservation islands to preserve honey bee subspecies and to implement research studies of adaptation to peculiar climatic conditions.

Determining the relationships between environmental variables and genetic diversity is critical to understand the processes that drive evolution in species-contact areas. We employed a combination of modeling approaches and multivariate statistical analyses to analyze mtDNA diversity in a hybrid zone between two evolutionary lineages of honeybees in order to interpret the microevolutionary processes that led to the observed spatial pattern of diversity. The model located the west European honeybee lineage mainly across temperate areas characterized by mild winters and high water availability throughout the year, whereas the African lineage was mainly associated with warmer and drier areas. Selection could be playing an important role in shaping the life history evolution, particularly affecting the mitochondria, and also resulting in hitchhiking effects on particular regions of the mitochondrial genome.