EurBee board Dorothea Brückner, Germany Norberto Milani, Italy Robert Paxton, Great Britain Dalibor Titěra, Czech Republic Bernard Vaissiere, France Program consultant

BEE SHOP session

6FP project PL 022568

We have found that apalbumin 1, the most abundant protein of RJ, is present in different forms: as a monomer, an oligomer subunits and water-insoluble aggregates as result of its interaction with fatty acids. MALDI-TOF MS analysis confirmed that apalbumin 1 and RJ peptide apisimin form a stable heterodimer.

An example of biological activity in relationship to the structures of some RJ peptides can be demonstrated on the antibacterial activity of apisimin in comparison to royalisin. Basic peptide royalisin, as other members of insect defensin´s family has well defined structure, stabilized by three disulphide bridges, while acidic serin-valin rich peptide apisimin creates predominantly helical structure with tendency to form oligomeric structures. Antibacterial activity of apisimin was observed only in its monomeric form (Bilikova et al, unpublished). Other example of biological potential of RJ proteins is stimulation of TNF-α release by monomeric apalbumin-1 in and apalbumin 2, but only low effect was observed in the case of oligomeric apalbumin-1 and/or apisimin, probably because amino acids sequential motifs of the apalbumin-1, responsible for stimulation of TNF- release are blocked by protein-protein interactions.

Acknowledgment

This work was supported by VEGA grant Agency of Ministry of Education of Slovak Republic and Slovak Academy of Sciences No.: 2/4059/04, Max-Planck Society for Partner Group of Slovak Academy of Sciences and by grant of 6RP EU-BeeShop No.: 022568.

Honey bee or Varroa mite adaptations in coexisting populations?

Ingemar Fries¹, Peter Rosenkranz<sup>2

1</sup> Sveriges Lantbruks Universitet, , 75007 Uppsala, Sweden

² Landesanstalt für Bienenkunde, Universität Hohenheim, Germany
E-mail: ingemar.fries©entom.slu.se

An isolated and non-managed honey bee population on the island Gotland in the Baltic Sea has been kept for over 7 years without treatments for mite control. After heavy colony losses the second, third and fourth year of the experiment colony vitality is increasing with lower winter mortality, increased swarming rates and decreased mite infestation rates. A field experiment has been set up to investigate if the host-parasite co-adaptation that has occurred is mainly based on mite or bee related characteristics. Mite population dynamics, using two different sources of mites, is studied in honey bees that survive without mite control and in colonies where mite levels have been continuously controlled. The first results from these investigations will be reported.

Several hive-based experiments were conducted to investigate the effects of virus transmission by bees and by mites on a range of important colony parameters, such as the survival rates of open and closed brood; the capping and emergence rates and the longevity of adult bees. A quantitative nucleic acid-based assay was developed to monitor the titres of several important bee viruses simultaneously, to replace the ELISA assays used in earlier experiments. Hive experiments using naturally established infections were supplemented with laboratory and hive experiments of single virus infections aimed at quantifying the transmission efficacies of different viruses, both by oral and mite-mediated transmission. Data from these earlier experiments shows elevated levels of larval and pupal removal related to exposure to viruliferous bees during the larval stage, although the capping and emergence rates appear largely unaffected. Mite-mediated virus transmission was far more efficient, with a slight peak in pupal susceptibility during the middle of the pupal period. Updated data using greater replication and the improved virus assays will be presented.

In-vitro reared drone larvae of several sister queens from an Apis mellifera ligustica and a Buckfast breeding line were infected with Paenibacillus larvae (type strain ATCC 9545) causing American Foulbrood (AFB). Although drone larvae were susceptible to AFB and could beinfected under in-vitro conditions there were differences within and between lineages. Infection resulted in a significant increase inmortality in the A. m. ligustica line but not in the Buckfast line. Different infection thresholds were found among sister queens of the A. m. ligustica line suggesting a considerable genetic variance for larval resistance against AFB. The results support a genetic model where asingle gene is responsible for differences in susceptibility to infection.

Centre National de la Recherche Scientifique, E-mail: solignac©legs.cnrs-gif.fr

The current honey bee linkage map comprises 2,008 microsatellite markers genotyped on 100 to 200 workers. The genetic length of the 16 linkage groups is 4,290, 4114 and 3902 cM respectively with the Haldane function of distance, the Kosambi function and the number of observed crossovers and hence its resolution is about 2 cM. Every genetic distance is below 10 cM. The map was used by the Baylor Center to organise 627 scaffolds of the sequence totalling 186 Mb and to orient most of them. A genetic map is the obligate complement of a sequence for association mapping studies but it may be associated to a haplotype map that depicts the pattern of linkage disequilibrium in natural populations. Haplotype maps are shaped by the variation of recombination along chromosomes, the regions of linkage equilibrium (steps) corresponding to hot spots and the regions of disequilibrium (blocks) to cold spots. We have taken advantage, for the two smallest chromosomes (15 and 16), of a map already more dense than that for the other chromosomes and of the superscaffolding effort (Robertson et al.). Only 5 and 4 gaps, probably very short, remain in the supperscaffolded sequence of chromosomes 15 and 16 respectively). We increase the density of markers to reduce every distance to 1 or 2 cM and extend the number of genotyped individuals (300 for the moment and in a short future 500). This will lead to precisely map the hot and cold spots common to all progenies on these chromosomes. In parallel, drones from a natural population are genotyped to construct a haplotype map. Because they are haploid, they offer the great advantage to provide directly the picture of linkage (dis)equilibrium and avoid the problem of double heterozygote markers in diplotypes. The main interest of these haplotype map is to provide a guideline for the choice of markers used to localise mendelian genes and QTLs since it is not useful, for a whole genome scan, to saturate with numerous markers the regions that are in strong linkage disequilibrium. Joined to the possibility of using bulk segregant analysis with drones (or monoandric families), these maps will considerably reinforce the efficiency of further genetic analyses.
Is Europe a desert for honeybees?

R. Jaffe, T. Shaibi, V. Dietemann, B. Kraus, R. Crewe, R.F.A. Moritz

Martin-Luther-Universität, Halle-Wittenberg, E-mail: rodolfo.jaffe©zoologie.uni-halle.de

The density of wild honeybee colonies (Apis mellifera) in the African deserts Sahara and Kalahari, as well as in two German national parks (Müritz and Hochharz), one city (Halle/Saale) and various apiaries, was estimated based on the genotypes of drones and worker offspring from mated queens. Estimated densities ranged between 4.5 - 6.4 colonies per square kilometer for the African deserts, being significantly higher than the colony densities in Germany, with estimates of 2.4 -3.2 colonies per square kilometer. These values closely match the nation wide density of colonies kept by beekeepers, showing that the densities of colonies observed in wild populations under the harsh conditions of the African deserts, exceed by far those observed in central Europe. We conclude that the apicultural activities in Europe are unlikely to compensate for the loss of habitats suitable for wild honeybees due to agriculture, forestry and other cultivation of land.

1University of Hohenheim, Apicultural State Institute, 70593 Stuttgart, Germany

2 Sveriges Lantbruks Universitet, 75007 Uppsala, Sweden

E-mail: peter.rosenkranz© uni-hohenheim.de

The so called “Bond-Project” performed at an isolated part of the island of Gotland in the Baltic Sea has confirmed that European honey bee colonies can survive without Varroa treatment for over 7 years. We recorded the population dynamics of Varroa infested honey bee colonies headed by queens which were bred and mated at Gotland together with non-selected control colonies from Hohenheim at an isolated military camp in South Germany. The first experiment during the season 2004 (queens from 2003) already indicated a lower increase of Varroa population throughout the season and a better fitness of the “Gotland-colonies” (n=7) under high infestation pressure compared to control colonies (n=9). At the end of 2005 we started a repetition of this experiment with a total of 25 colonies. We included the comparative investigation of some tolerance factors like reproductive capacity of Varroa females and hygienic behavior of the bees.

First results will be presented including a critical evaluation of the methods used for host and parasite population dynamic measurements.