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

Macroparasites

Cape honeybee workers, A. m. capensis, are facultative social parasites and can have a dramatic impact on queenright colonies of other subspecies such as the neighbouring one, A. m. scutellata. In South Africa, this “dwindling colony syndrome” is caused by a single clonal lineage, which we here use to study the underlying proximate mechanisms of social parasitism by workers. Initially infesting workers can easily overcome the inhibitory pheromone secretion of the host queen and brood, because 94 % of them develop into pseudoqueens. However, the reproductive development of their own offspring is inhibited (3,1 %), suggesting that the parasitic pseudoqueens together are more efficient than the host queen at regulating reproduction. Indeed, in paired arena tests, single parasitic workers were pheromonally dominant over all other worker groups and even over A. m. scutellata queens. This indicates an outstanding ability for pheromonal competition, because the reproductive division of labour in this highly eusocial species can be challenged. Thus, it appears as if the ability to both overcome and produce inhibitory pheromones is crucial for social parasitism by honeybee workers.

Abandoned honeybee nests can serve as a nutrition source and breeding substrate and habitat for a variety of arthropods as small hive beetles (=SHB), Aethina tumida, and greater wax moths (=GWM), Galleria mellonella. Differences in preparation for absconding between European and African honeybee subspecies may influence the reproductive success of these pests. Absconding African colonies (N=14) left significantly less brood and stores behind than European ones (N=19; p<0.05). , While SHB reproduction was significantly reduced by the preparation efficacy for protein sources of the respective honeybee subspecies (pollen: r_s=0.9, t=4.3, p=0.008; brood: r_s=0.9, t=3.7, p=0.014), this was not the case for GWM reproduction, which occurred even on empty old brood combs. SHB reproduced significantly less often in abandoned African nests (0%) than in European ones (63%; p=0.001), while there were no significant differences in the frequency of reproduction of the moths (27% and 63%; p>0.05). Both pests tended to negatively influence the reproductive success of each other. There was also a negative influence of ants on SHB reproduction. In contrast to moth larvae, SHB larvae did not completely destroy the combs. Consequently, moths could still reproduce in nests after SHB mass reproduction, but not the other way around. We conclude that the preparation efficacy for absconding has a major impact on SHB reproduction and may contribute to both the invasion success of SHB in its new ranges.

Swiss Bee Research Centre, Agroscope Liebefeld-Posieux, Swiss Federal Research Station for Animal Production and Dairy Products (ALP), Schwarzenburgstrasse 161, CH-3003 Bern, Switzerland

When parasites of social insect bees become invasive species, they may cause severe damage to non-sympatric hosts. The small hive beetle (SHB), Aethina tumida, is a parasite and scavenger of honeybee, Apis mellifera, colonies native to Africa and has a higher impact in populations of European-derived hosts in North America and Australia. Frequent collapses of European-derived colonies probably result from quantitative differences in a range of behaviours between African and European honeybee subspecies. Thus, the higher susceptibility of European-derived honeybees, being itself an invasive species in North America and Australia, seems to facilitate the spread of SHB, another invasive species. Bumblebees and stingless bees naturally occur in the new SHB ranges and share important features with honeybees, suggesting that a host switch from honeybees may occur. Experiments were conducted using colonies of Bombus impatiens and Trigona carbonaria. The data show that both bumblebee and stingless bee colonies are attractive to free-flying SHB, indicating that they can actually serve as alternative hosts. However, behavioural resistance mechanisms were found in both B. impatiens and T. carbonaria. This suggests that general behavioural defence mechanisms against nest intruders also seem to provide protection against invasive species. Nevertheless, our results indicate a potential for an invasion meltdown in social bees. The actual impact of this on native biodiversity will depend on the infestation levels of bumblebee and stingless bee colonies by SHB in the field. It will also depend on the impact of SHB on feral honeybees in Australia and America.

trichilia bv, E-mail: marieke.mutsaers©planet.nl

Since the recent introduction of the African small hive beetle Aethina tumida (Coleoptera, Nitiludae) into other parts of the world it has become relevant to gather more information about hive beetles and other pests in subsaharan Africa where they are indigenous. Until now most records are from South Africa, from beekeepers and bee researchers, but there are some reports from other areas as well.

The opinion exists that the small hive beetle is less noxious in their area of origin than in most countries where they have been introduced recently. But there are beekeepers in Africa who consider the pest as a serious threat to colony development and honey quality. In West Africa the small hive beetle seems to be a bigger problem than in East Africa or the Horn of Africa. Ecological conditions such as climate and soil humidity, but also the occurrence of predators and parasites may differ regionally.

The word hive in the name hive beetle may suggest that the beetles occur mainly in man-made or man-provided housing for honeybee colonies, but the word hive is also used for feral colonies of honeybees hosting them. Besides there are also stingless bee species, for example Dactylurina staudingerii (Meliponini) which are hosts to the small hive beetle.

Male fitness in relation to colony development and varroosis infection

R. Büchler¹, R. Moritz², C. Garrido¹, K. Bienefeld³, K. Ehrhardt<sup>3

1</sup> LLH – Bieneninstitut Kirchhain, Germany, ² Institut für Zoologie der Universität Halle, Germany,
³ Länderinstitut für Bienenkunde Hohen Neuendorf, Germany, E-mail: buechlerr©llh.hessen.de

Numerous investigations confirm strong effects of Varroa destructor infestations on colony development and the viability (flying ability, life expectancy, number of spermatozoa etc.) of Apis mellifera drones. For a better understanding of natural selection processes and with regard to the selection of Varroa tolerant bee stock we want to estimate the influence of Varroa infestation on the male mating success of bee colonies.

In 2005, we used the island mating station of Norderney to compare the colony development and mating success of 26 widely untreated sister colonies under isolated conditions. The strength of colonies, the extend of drone brood, the number of adult drones, the Varroa and virus infection level of bee and brood samples were repeatedly checked throughout the season. A set of closely linked microsatellites allowed to distinguish the genotypes of the 26 drone colonies and to determine the paternity of about 10 worker bees from each of 48 queens mated in three successive periods on the mating station.

The drone population and mite infestation varied considerably between the colonies. The worker bee infestation increased rapidly and had significant influence on the shape of the colonies during the late drone season. The effects of colony development, mite and virus infestation on the realized mating success of individual drone colonies will we presented.

AFSSA, E-mail: m.aubert©afssa.fr

As Varroa destructor is a major pest of the honey bee (Apis mellifera), its control is a key point in the beekeeping industry. After entering bee larva cells prior capping, V. destructor female lays eggs on the honey bee pupa. Mite nymphs develop in capped brood feeding on haemolymph of its host. In France the use of APIVAR^® strips has been the most legally recommended and the most frequently used treatment against V. destructor. However some beekeepers reported that APIVAR^® strips were not as effective as they used to be.

An efficacy trial has been run on 15 colonies from our experimental apiary. APIVAR^® treatment was applied on ten colonies. Sticky boards were installed at the bottom of the hives in order to collect falling varroas. After 12 weeks, strips were removed and residual mites in colonies were killed using three active ingredients successively: oxalic acid, coumaphos (ASUNTOL^®) and fluvalinate (APISTAN^® strips). In the treated group, zero to 14 mites were counted during and following these last three treatments. This represents zero to 1.1% of the total number of mites collected during the whole experiment in each of the ten tested colonies. On the opposite, the same three treatments entailed the fall of 233 to 942 mites in the five control colonies to which no APIVAR^® strips had been applied.

In our experimental conditions, efficacy of APIVAR^® treatment was found to be very high.

Moreover, our results illustrate that a simple checking of mite infestation before winter may give a false security to bee-keepers. A mild number of parasites fallen following a single control does not give account of the long period during which the colony has been bearing a large number of parasites. On the opposite, colonies treated with APIVAR^® are freed from most of their parasites since the third week of treatment.

Centro de Investigação de Montanha, Escola Superior Agrária de Bragança,

Campus de Santa Apolónia, 5300-955 Bragança, Portugal
E-mail: mvboas©ipb.pt

The use of acaricides in organic beekeeping is legally restricted to essential oils and some organic acids, since no synthetic compound can be added to the honey matrix. Thymol, formic and oxalic acid are the main alternatives to control varroa mite, used all over the world with good results. Although these chemicals are already present in honey and should not cause any contamination problem, their continuous use in beekeeping necessarily has some effect in the quality of honey. In this work we followed honey residues of thymol applied, at organic honey production mode apiaries with two different methodologies.

Thymol was applied in paper strips after diluted in olive oil. In each treatment 16 grams of thymol were introduced into a group of eight Langstroth hives. This procedure was repeated during spring (March/April) and autumn (October/November) over three years in four apiaries. Alternatively, thymol was added in impregnated wax foundation with either 9 or 18 grams of thymol per frame. One treatment corresponds to the use of either two frames of beeswax foundations with 9 g/frame or one frame with 18 g/frame. Each one of these latter methods was applied in two groups of seven hives. Honey samples were collected during harvest (September) from all hives, as well as from hives with any varroa treatment. Thymol levels in honey were measured by gas-chromatography with FID detector, after SPE extraction.

From the analytical results we concluded that honey have already a natural content in thymol that seems to increase when thymol is used as acaricide. Although, the levels found do not reach the value of 0,8 mg/kg, (MRL in Switzerland), above it affects the honey taste. Comparatively, the use of impregnated beeswax foundations seems to contribute more significantly to the thymol residues, specially if treated with 18 g/frame.

Since 2003 the Kónya rotating-broodframe beehive (www.anivet.hu) is advertised as a method of augmenting the honey yield, preventing bee colonies from swarming and of Varroa destructor control.

In a triennial study we investigated the effect of unnatural movements of brood combs by 1) weekly rotating all brood combs of 6 colonies during the swarm season, 2) daily manipulating brood combs out of 8 colonies on three different ways: control = comb never touched, rotated = comb rotated 180∨dm; vertically, shaken = comb hit on the ground three times with 40-50g, 3) using the replica of a rotating-broodframe beehive for one season.

Weekly rotation of brood combs neither influenced the population dynamics of honey bees or Varroa-mites nor altered the honey yield. However, in contrast to control colonies most test colonies could be prevented from swarming as weekly rotating causes elimination of swarm cells. Daily rotating or shaking of brood cells did neither affect fertility (93-100%) nor fecundity (2.6-3.0) of reproductive mites or mortality of mite offspring in the brood cells. Independently of the type of manipulation both types of mates were only present in 11-43% of single-infested cells shortly before hatching of the young bee. The mites’ orientation in the brood cell solely seems to be impeded in terms of the position of the fecal accumulation, which was randomly distributed only in rotated cells. A colony kept in the rotating-broodframe beehive died from extremely high Varroa-infestation after one season. Thus, we can not confirm any effect of unnatural movements of brood combs on developing bees or reproductive Varroa-mites, respectively.

University of Hohenheim, Apicultural State Institute1, Zoological Institute, FG Tierökologie2

E-mail: sandy-sun©gmx.li; peter.rosenkranz© uni-hohenheim.de, j .steidle©uni-hohenheim.de

The small hive beetle (SHB) is native to Southern Africa where it is a relatively harmless parasite within the honey bee hive. As an invasive species in the USA and Australia the SHB became a threat to beekeeping causing economic damages and even losses of colonies.

One strategy for the treatment and monitoring of the SHB inside the hive is the use of traps in combination with volatile substances which are attractive to the beetle. Therefore, we observed the aggregation and mating behaviour of SHB in plastic cages according to age, mating status and environmental condition. In further olfactometer bioassays we tested the solvent extracts of SHB, which were attractive to other beetles. Additionally, first chemical analysis of extracts from SHB of different age and sex using GC-MS methods are presented.

Under laboratory condition the SHB showed positive reactions toward other beetles of specific stages. However, our preliminary results indicate some obstacles, as we could prove that beetles reared in the laboratory showed differences in their preference behaviour compared to wild beetles, probably due to specific rearing conditions. Further premise for a successful SHB bioassay are revealed through the fact that preference behaviour of the SHB is more pronounced if thigmotactic stimuli are involved in the bioassay.

The requirements for a “standard SHB bioassay” and the possibilities of using the aggregation and mating behaviour of the SHB for a trap within the hive are discussed.

This work is supported by the Federal Agency for Agriculture and Food (BLE)

Breeding value estimation based on a BLUP (Best Linear Unbiased Prediction) animal model is an approved method for the genetic evaluation of traditional traits of the honey bees such as honey yield, gentleness or swarming, cf. the database at www.beebreed.eu .

In order to introduce a more advanced selection criteria which includes the resistance of a bee colony against Varroa destructor an indirect selection strategy is required, because no direct resistance parameters are obviously measurable. Auxiliary traits like the number of dead mites after chemical treatment in summer, the defence behaviour of the bees (proportion of damaged mites) and their hygienic behaviour (guessed by the pin test) which have been collected in Germany during the last years were utilised instead of.

To this end the BLUPF90 code as well as the AIREMLF90 software, which is used to estimate genetic parameters, were adapted to the peculiarities of honey bee pedigrees by introducing a dummy father model in order to approximate the paternal descent at each mating station. Hence the genetic relatedness and inbreeding are estimated more correctly.

Heritabilities estimated by this approach are presented as well as the genetic correlations between the traits. Additionally, an alternative approach for estimating the infestation of the colony by varroa mites is proposed which is based on counting the natural drop of dead mites in spring as well as the number of phoretic mites within a sample of bees taken from the colony in July.


Acaricide (fluvalinate and acrinathrin) residues in Czech beeswax

J. Hofbauer², P. Krieg<sup>1

1</sup> Bee Research Institute Ltd.Dol. Beestation, Přerov –Žeravice pavel.krieg©tiscali.cz

² Research Institute for Fodder Crops, Ltd. Troubsko hofbauer©vupt.cz

In years 2002-2005 we dealt with analytics and determination of fluvalinate and acrinathrin in beeswax, foundations and propolis by using of gas chromatography and ECD detector by chromatograph Agilent Technologies 6820.

The foundations were obtained from the major providers from Czech Republic. We have not found any detectable amounts of fluvalinate and acrinathrin residues. The detection sensitivity was up to 0,5 mg/kg of wax in fluvalinate and 0,1 mg/kg of wax in acrinathrin. These agents are lipophilous and cannot be eliminated of wax, so they can infiltrate out of wax into honey. The results showed that the residues amount can be ten times lower in honey, i.e. up to 0,05 mg/kg of honey in fluvalinate and up to 0,01 mg/kg of honey in acrinathrin.

The situation in other countries is much worse. Fluvalinate was found in beeswax in amount 1,9-2,9 mg/kg of wax.

The import of cheap beeswax, that could be contaminated with these agents, or the exchange of foreign wax for foundations endanger the Czech honey production at present. The residues contained in this wax could get into the foundations and consequently into honey. In future it is necessary to examine the residual content in foundations.

The results are part of project No. QD1061 from agency NAZV MZe of the Czech Republic.

PPO Bee Unit, Wageningen, The Netherlands, E-mail: lonne.gerritsen©wur.nl

When honey bees are infected by Varroa destructor mites during their larval and pupal stage they have a shorter lifespan. In this poster we show how V. destructor infection effects survival of winter bees in an experiment done during the winter of 2005-2006.


Brood and worker bee viability and cellular responses after acaricide applications in honeybee colonies

Aleš Gregorc

Agricultural Institute of Slovenia, Hacquetova 17, 1001 Ljubljana, Slovenia, E-mail: ales.gregorc©kis.si

The removed brood from comb cells were counted and marked in situ after an oxalic acid (OA)/sucrose or 1% rotenone powder treatment. OA caused 18.7% capped brood removal while 1% rotenone powder 75.2%. The rotenone treatment trig higher brood removal rate (P<0.01) and replacement with young brood than OA or control water treatment. OA solutions of 2.97% OA/31.95% sucrose, 3.40% OA/47.62% sucrose, 3.73% OA/27.10% sucrose and a control, 32% sugar-only solution resulted in death rates of 10.72%, 14.30%, 9.37% and 6.36% respectively in caged worker bees. Bee mortality was higher in the OA treated bees than it was in the sugar solution treated bees (P0.05). Individually treated bees were prone to drink sugar or OA solutions in negative relation according to the OA concentration. Cell death was detected after OA or formic acids (FA) treatment of honeybee larvae using the TUNEL technique for DNA labelling. In 3- and 5-day-old larvae exposed to OA, cell death was found in 25% of midgut epithelial cells 5 hours after the treatment and increased to 70% by the 21^st hour. Fifty hours after the application, cell death was reduced on to 18 % of the epithelial cells of the 3-day-old larvae and had increased to 82 % in the 5-day-old larvae. Evaporated FA induced extensive apoptotic cell death in the peripheral, cuticular and subcuticular tissues that preceded the cell death of the entire larval body. In old worker bees cell death was detected in 48% of the columnar epithelial cells of the midgut 12 hours after an OA treatment, falling away to 20% after 24 hours. The possible effects of OA on the tissues of brood stage or adult worker bees are discussed in this study.
Course of Varrroa destructor invasion in bee colonies treated with amitraz

Rajmund Sokół, Konstanty Romaniuk, Wiesław Witkiewicz

University of Warmia and Mazury in Olsztyn (Poland), E-mail: sokol©uwm.edu.pl

In 1987-2005 in 20-30-hive stationary apiary, bee colonies were treated against Varroa destructor with preparation containing 12.5 mg of amitraz (Apiwarol AS – in the form of a fumigating tablets, Biowet, Poland) according to the own programme; additionally sealed drone broad was cut off. The efficacy of Varroa control was evaluated after the end of treatment (September).

In 1987-1991 females of V. destructor were found in all bee colonies, although its number on bees varied and fluctuated between 0.6 and 4.5 in sample of 100 insects.

Since 1992 number of colonies, in which parasites were found after the last treatment, decreased to 19-52% as well as number of Varroa mites in 100 bees ( to 0.4-0.7).

The results of presented studies indicate, that regular applying of amitraz by spring 1991 and next after the last honey harvest, and since 1992 only late-summer fumigation (end of July-September) in visible way reduced extensity as well as intensity of V. destructor invasion.

This so low intensity of V. destructor invasion in bee colonies shows high effectiveness of amitraz and lack of parasite resistance to this substance. The presented manner of varrosis treatment combined with cutting off sealed drone broad, turned out very effective and cheap.