Reproductive success of the parasitic mite (Varroa destructor) is lower in honeybee colonies that target infested cells with recapping

Cell recapping is a behavioural trait of honeybees (Apis mellifera) where cells with developing pupae are uncapped, inspected, and then recapped, without removing the pupae. The ectoparasitic mite Varroa destructor, unarguably the most destructive pest in apiculture world-wide, invades the cells of developing pupae to feed and reproduce. Honeybees that target mite infested cells with this behaviour may disrupt the reproductive cycle of the mite. Hence, cell recapping has been associated with colony-level declines in mite reproduction. In this study we compared the colony-level efficacy of cell recapping (how often infested cells are recapped) to the average mite fecundity in A. mellifera. Our study populations, known to be adapted to V. destructor, were from Avignon, France, Gotland, Sweden, and Oslo, Norway, and were compared to geographically similar, treated control colonies. The results show that colonies with a higher recapping efficacy also have a lower average mite reproductive success. This pattern was likely driven by the adapted populations as they had the largest proportion of highly-targeted cell recapping. The consistent presence of this trait in mite-resistant and mite-susceptible colonies with varying degrees of expression may make it a good proxy trait for selective breeding on a large scale

Bee health field tool

The Bee health field tool (related with the most important and actual technical constraint in beekeeping are the technical features related with bee diseases and nutrition) was developed in a format that can be easily used in the field by all beekeepers, independent of their background, using an innovative learning strategy - gamification – that provides an effective, informal learning environment, and helps learners practice real-life situations and challenges in a safe environment. The Bee health field is part of the contents of the MOOC course curriculum allowing to achieve a training skill and specialization in bee health and nutrition. The expected impact is related with the possibility of enabling beekeepers to acquire the best and innovative beekeeping techniques and skills in this area of the production itinerary. This knowledge and skills are essential for the professionalization of beekeepers as the survival of the bees is compromised by the pressures related with these issues. Furthermore, the Bee health is the main factor for improving the beekeeping performance and for increasing the production and quality of the bee products in order to achieve adequate economic profits. It is also expected to have an impact in the active learning sector, by the development and use of gamifications as training tool.info:eu-repo/semantics/publishedVersio

Development of SNP and microsatellite markers for goldsinny wrasse (Ctenolabrus rupestris) from ddRAD sequencing data

Wrasse (Labridae) species have been used as parasite cleaners in Atlantic salmon farming since the 1980s. However, their use has recently escalated, with millions now being introduced into salmon cages each year. Most fish are of wild origin, their exploitation potentially impacting native populations. Genetic information is urgently required to inform management decisions. We identified 174 microsatellite and 149 SNP markers from ddRAD sequence data. From these, 17 and 48 microsatellite and SNP markers, respectively, were validated by genotyping 150 goldsinny wrasse collected from five locations along the Norwegian and Swedish coasts. Two to 30 alleles were identified at the microsatellite loci, while gene diversity (He) ranged 0.101–0.907. All SNP loci were biallelic, with averagedHeper locus ranging between 0.063 and 0.495

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

The 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.Pint

Genetic analysis of goldsinny wrasse reveals evolutionary insights into population connectivity and potential evidence of inadvertent translocation via aquaculture

The salmon industry is heavily dependent on wrasse for delousing infected fish. The goldsinny wrasse is numerically the most important, and each year, millions are harvested from the wild and transported large distances into fish farms. Population genetic knowledge is required to sustainably exploit this species. Here, 1051 goldsinny wrasses from 16 locations across Scandinavia, the British Isles, and Spain were genotyped with 14 microsatellite and 36 SNP markers. Within-population genetic diversity decreased towards north, and a genetic break was observed across the North Sea. Samples from Northern Norway differed from rest of the Scandinavian samples, and samples from the British Isles differed from the Spanish ones. Within Scandinavia, isolation-by-distance was detected. Observed genetic patterns fitted well with expectations derived from oceanographic drift simulations. A sample from mid-Norway deviated from these patterns however, and was genetically very similar to southern Scandinavian samples. We conclude that the population structure of this species is primarily determined by the opposing evolutionary forces of passive drift, limited adult migration and spawning-site fidelity, whereas the deviation in isolation-by-distance observed in mid-Norway is potentially caused by inadvertent translocations of wrasse from southern Scandinavia via current aquaculture practise. Inclusion of outlier loci gave greater resolution, suggesting that diversifying selection may also affect population structuring among goldsinny wrasses

Honey recipes

info:eu-repo/semantics/publishedVersio

Honey bee predisposition of resistance to ubiquitous mite infestations

Host-parasite co-evolution history is lacking when parasites switch to novel hosts. This was the case for Western honey bees (Apis mellifera) when the ectoparasitic mite, Varroa destructor, switched hosts from Eastern honey bees (Apis cerana). This mite has since become the most severe biological threat to A. mellifera worldwide. However, some A. mellifera populations are known to survive infestations, largely by suppressing mite population growth. One known mechanism is suppressed mite reproduction (SMR), but the underlying genetics are poorly understood. Here, we take advantage of haploid drones, originating from one queen from the Netherlands that developed Varroa-resistance, whole exome sequencing and elastic-net regression to identify genetic variants associated with SMR in resistant honeybees. An eight variants model predicted 88% of the phenotypes correctly and identified six risk and two protective variants. Reproducing and non-reproducing mites could not be distinguished using DNA microsatellites, which is in agreement with the hypothesis that it is not the parasite but the host that adapted itself. Our results suggest that the brood pheromone-dependent mite oogenesis is disrupted in resistant hosts. The identified genetic markers have a considerable potential to contribute to a sustainable global apiculture

Managed honey bee colony losses in Canada, China, Europe, Israel and Turkey, for the winters of 2008-9 and 1009-10

In 2008 the COLOSS network was formed by honey bee experts from Europe and the USA. The primary objectives set by this scientific network were to explain and to prevent large scale losses of honey bee (Apis mellifera) colonies. In June 2008 COLOSS obtained four years support from the European Union from COST and was designated as COST Action FA0803 – COLOSS (Prevention of honey bee COlony LOSSes). To enable the comparison of loss data between participating countries, a standardized COLOSS questionnaire was developed. Using this questionnaire information on honey bee losses has been collected over two years. Survey data presented in this study were gathered in 2009 from 12 countries and in 2010 from 24 countries. Mean honey bee losses in Europe varied widely, between 7-22% over the 2008-9 winter and between 7-30% over the 2009-10 winter. An important finding is that for all countries which participated in 2008-9, winter losses in 2009-10 were found to be substantially higher. In 2009-10, winter losses in South East Europe were at such a low level that the factors causing the losses in other parts of Europe were absent, or at a level which did not affect colony survival. The five provinces of China, which were included in 2009-10, showed very low mean (4%) A. mellifera winter losses. In six Canadian provinces, mean winter losses in 2010 varied between 16-25%, losses in Nova Scotia (40%) being exceptionally high. In most countries and in both monitoring years, hobbyist beekeepers (1-50 colonies) experienced higher losses than practitioners with intermediate beekeeping operations (51-500 colonies). This relationship between scale of beekeeping and extent of losses effect was also observed in 2009-10, but was less pronounced. In Belgium, Italy, the Netherlands and Poland, 2008-9 mean winter losses for beekeepers who reported ‘disappeared’ colonies were significantly higher compared to mean winter losses of beekeepers who did not report ‘disappeared’ colonies. Mean 2008-9 winter losses for those beekeepers in the Netherlands who reported symptoms similar to “Colony Collapse Disorder” (CCD), namely: 1. no dead bees in or surrounding the hive while; 2. capped brood was present, were significantly higher than mean winter losses for those beekeepers who reported ‘disappeared’ colonies without the presence of capped brood in the empty hives. In the winter of 2009-10 in the majority of participating countries, beekeepers who reported ‘disappeared’ colonies experienced higher winter losses compared with beekeepers, who experienced winter losses but did not report ‘disappeared’ colonies

Local variation in recombination rates of the honey bee (Apis mellifera) genome among samples from six disparate populations

Meiotic recombination is an essential component of eukaryotic sexual reproduction, but its frequency varies within and between genomes. Although it is well established that honey bees have a high recombination rate with about 20 cM/Mbp, the proximate and ultimate causes of this exceptional rate are poorly understood. Here, we describe six linkage maps of the western honey bee Apis mellifera that were produced with consistent methodology from samples from distinct parts of the species near global distribution. We compared the genome-wide rates and distribution of meiotic crossovers among the six maps and found considerable differences. Overall similarity of local recombination rates among our samples was unrelated to geographic or phylogenetic distance of the populations that our samples were derived from. However, the limited sampling constrains the interpretation of our results, because it is unclear how representative these samples were. In contrast to previous studies, we found only in two datasets a significant relation between local recombination rate and GC content. Focusing on regions of particularly increased or decreased recombination in specific maps, we identified several enriched gene ontologies in these regions and speculated about their local adaptive relevance. These data are contributing to an increasing comparative effort to gain an understanding of the intra-specific variability of recombination rates and their evolutionary role in honey bees and other social insects.The National Institute of General Medical Sciences of the National Institutes of Health under award number R15GM102753, the US National Science Foundation (DMS #1359187) and UNCG.http://link.springer.com/journal/402020-11-30hj2020Zoology and Entomolog

Virus Prevalence in Egg Samples Collected from Naturally Selected and Traditionally Managed Honey Bee Colonies across Europe

Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across Europe were screened for the prevalence of different viruses. Screenings were performed using the phenotyping protocol of the 'suppressed in ovo virus infection' trait but with qPCR instead of end-point PCR and a primer set that covers all DWV genotypes. Of the 213 screened samples, 109 were infected with DWV, 54 were infected with black queen cell virus (BQCV), 3 were infected with the sacbrood virus, and 2 were infected with the acute bee paralyses virus. It was demonstrated that incidences of the vertical transmission of DWV were more frequent in naturally surviving than in traditionally managed colonies, although the virus loads in the eggs remained the same. When comparing virus infections with queen age, older queens showed significantly lower infection loads of DWV in both traditionally managed and naturally surviving colonies, as well as reduced DWV infection frequencies in traditionally managed colonies. We determined that the detection frequencies of DWV and BQCV in honey bee eggs were lower in samples obtained in the spring than in those collected in the summer, indicating that vertical transmission may be lower in spring. Together, these patterns in vertical transmission show that honey bee queens have the potential to reduce the degree of vertical transmission over time