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Brood Cells

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J Beetsma – 1st expert on this subject based on the ideXlab platform

  • attractiveness of Brood Cells from different honey bee races apis mellifera to varroa mites
    , 2006
    Co-Authors: J N M Calis, W J Boot, J Beetsma

    Abstract:

    Reproduction of the Varroa mite only occurs inside capped Brood Cells of honey bees. Therefore, invasion into Brood Cells is crucial for the mite’s reproduction and the rate of invasion will affect the growth of the mite population. We investigated the invasion response of the mites to drone or worker larvae of different honey bee races, because selection for less attractive Brood may help Varroa mite control. We compared attractiveness of Brood Cells in 3 or 6 hour intervals before cell capping, because invasion response of the mites increased strongly with the age of both worker and drone larvae. The results suggest that not the racial origin of the worker Brood, but the distance between the larva and the cell rim affected the invasion response of the Varroa mites to worker Brood Cells. Possibilities to obtain less attractive Brood via selection seem to be limited.

  • invasion behaviour of varroa jacobsoni oud from bees into Brood Cells
    Apidologie, 1999
    Co-Authors: J Beetsma, W J Boot, J N M Calis

    Abstract:

    L’acarien Varroa jacobsoni (Acari : Varroidae) peut envahir les cellules de couvain d’ouvrieres (cco) ou de mâles (ccm) d’abeilles (Apis mellifera L.) lorsque les ouvrieres le mettent en contact etroit avec ces cellules. Les acariens passent du flanc de l’abdomen de l’abeille sur le rayon et penetrent immediatement dans la cellule de couvain adjacente, grimpent a la surface de la larve et se glissent entre la larve et la paroi de la cellule jusqu’au fond de celle-ci. On n’a jamais vu d’acariens se deplacer sur le rayon ni entrer dans des cellules de couvain et en ressortir pour choisir une cellule a envahir [10]. A l’aide de « demi-rayons », Boot et al. [8 ] ont pu enregistrer le moment ou un acarien apparaissait au fond de la cellule transparente et le moment ou la cellule etait operculee. L’ invasion des acariens dans les cco s’est produite entre 15 et 20 h avant l’operculation de la cellule, alors que dans les ccm elle a commence 45 a 50 h avant l’operculation. La periode d’attractivite des ccm est donc 2 a 3 fois plus longue que celle des cco. Boot et al. [13] ont mesure i) la periode d’attractivite des cellules de couvain, ii) la repartition des acariens sur les differents types de cellules, et iii) la distance entre la larve et le bord de la cellule de divers types de cellules, en relation avec la duree qui a precede l’operculation. La periode d’attractivite des cco et des ccm raccourcies a ete plus longue et on y a trouve 1,5 a 3 fois plus d’acariens que dans les cellules temoins. La periode d’attractivite des cco allongees a ete plus courte et elles ne renfermaient qu’un sixieme des acariens presents dans les cellules temoins. Les cellules de mâles avec une larve d’ouvriere semblent avoir eu une periode d’attractivite plus courte et ne renfermaient que la moitie des acariens trouves dans les cco temoins. Les cellules d’ouvrieres avec une larve de mâle semblent avoir eu une periode d’attractivite plus longue, mais le nombre d’acariens ne differait pas de celui trouve dans les ccm temoins. L’attractivite des cellules de couvain semble etre en rapport avec la distance entre la larve et le bord de la cellule. On a estime la distance critique a laquelle les acariens envahissaient les cellules de couvain, en mesurant cette distance au debut de la periode d’attractivite. Dans les cco allongees et dans les ccm enfermant une larve d’ouvriere, la distance critique etait plus grande que dans les cco temoins. Puisque la periode d’attractivite etait plus courte dans ces deux cas la, les larves etaient plus âgees lorsque les acariens ont commence a envahir les cellules. A partir de colonies indemnes d’acariens, Calis et al. [20] ont obtenu des rayons de couvain date. Lorsque les premieres cellules de couvain ont commence a etre operculees. les rayons ont ete places durant 3 h dans une colonie fortement infestee, puis remis dans les colonies indemnes. L’operculation des cellules de couvain a ete observee toutes les 3 h. Le nombre relatif d’acariens qui envahissaient les cellules a augmente avec l’âge de la larve. Boot et al. [9] ont introduit un grand nombre d’acariens jeunes et vieux dans une colonie indemne et les ont laisse une journee. Les acariens ont commence a envahir les cellules de couvain au premier jour du stade phoretique et ont continue a le faire a un taux constant, bien que ce taux et le nombre d’abeilles aient varie d’une repetition a l’autre.

  • Effective biotechnical control of varroa: applying knowledge on Brood cell invasion to trap honey bee parasites in drone Brood
    Journal of Apicultural Research, 1999
    Co-Authors: J.n.m. Calis, J Beetsma, W.j. Boot, J. Van Den Eijnde, A. De Ruijter, J.j.m. Van Der Steen

    Abstract:

    SUMMARYBiotechnical methods of varroa (Varroa jacobsoni) control are based on the idea that mites inside Brood Cells are trapped and can then easily be removed from a honey bee (Apis mellifera) colony. Trapping is most efficient using drone Brood in otherwise Broodless colonies. In theory, one trap-comb with drone Brood is enough to achieve control. We designed and tested two methods using trap-combs with drone Brood. In the first experiment, effectiveness of the control method varied considerably, from 67% to 96%. However, the observed effectiveness in each separate colony was similar to the prediction based on knowledge of behaviour of mites invading Brood Cells. Effectiveness depended on the number of drone Cells that had been available for mite trapping. In the second experiment, we adjusted the method to improve production of trap-combs with drone Brood, since this appeared to be crucial for trapping efficiency. The observed effectiveness of 93.4% demonstrates that trap-combs with drone Brood can eff…

W.j. Boot – 2nd expert on this subject based on the ideXlab platform

  • Effective biotechnical control of varroa: applying knowledge on Brood cell invasion to trap honey bee parasites in drone Brood
    Journal of Apicultural Research, 1999
    Co-Authors: J.n.m. Calis, J Beetsma, W.j. Boot, J. Van Den Eijnde, A. De Ruijter, J.j.m. Van Der Steen

    Abstract:

    SUMMARYBiotechnical methods of varroa (Varroa jacobsoni) control are based on the idea that mites inside Brood Cells are trapped and can then easily be removed from a honey bee (Apis mellifera) colony. Trapping is most efficient using drone Brood in otherwise Broodless colonies. In theory, one trap-comb with drone Brood is enough to achieve control. We designed and tested two methods using trap-combs with drone Brood. In the first experiment, effectiveness of the control method varied considerably, from 67% to 96%. However, the observed effectiveness in each separate colony was similar to the prediction based on knowledge of behaviour of mites invading Brood Cells. Effectiveness depended on the number of drone Cells that had been available for mite trapping. In the second experiment, we adjusted the method to improve production of trap-combs with drone Brood, since this appeared to be crucial for trapping efficiency. The observed effectiveness of 93.4% demonstrates that trap-combs with drone Brood can eff…

  • Control of varroa by combining trapping in honey bee worker Brood with formic acid treatment of the capped Brood outside the colony: putting knowledge on Brood cell invasion into practice
    Journal of Apicultural Research, 1998
    Co-Authors: J.n.m. Calis, J Beetsma, W.j. Boot, J. Van Den Eijnde, A. De Ruijter, J.j.m. Van Der Steen

    Abstract:

    SUMMARYBiotechnical varroa (Varroa jacobsoni) control methods are based on the principle that mites inside Brood Cells are trapped and then removed from the bee colony. In our experiments trapped mites were killed with formic acid. Worker Brood used for trapping was retained and returned to the colonies. The observed percentage of mites trapped and killed by formic acid treatment was 87% and 89% in two experiments. The effectiveness could be predicted using prior knowledge on Brood cell invasion behaviour, which thus proved to be valid for the design and improvement of trap-comb methods for ecological varroa control.

  • further observations on the correlation between attractiveness of honey bee Brood Cells to varroa jacobsoni and the distance from larva to cell rim
    Entomologia Experimentalis Et Applicata, 1995
    Co-Authors: W.j. Boot, J.n.m. Calis, Ronald G. Driessen, J Beetsma

    Abstract:

    Varroa jacobsoni Oudemans (Acari: Varroidae) was studied with respect to invasion into different types of honeybee, Apis mellifera L., Brood Cells. Different cell types were obtained by shortening and elongating of Cells, grafting worker larvae into drone Cells and vice versa. The type of cell strongly affected the number of mites per cell, and the attractive period of the Cells to the mites. The type of cell also affected the distance from larva to cell rim preceding cell capping. When this distance was larger in comparison to control Cells of the same age, the attractive period of the Brood Cells was shorter and vice versa. Since in all cell types the distance from larva to cell rim continuously decreased preceding cell capping, this negative correlation is in agreement with the hypothesis that there is a critical larva-rim distance under which Brood Cells are attractive to mites. Then, the length of the attractive period of Brood Cells depends on the moment this critical distance is reached. The distribution of mites over different cell types in turn results from differences in the attractive period.

Stefan Fuchs – 3rd expert on this subject based on the ideXlab platform

  • geometric approximation of the infestation of honey bee Brood Cells by varroa jacobsoni and implications for the estimation of Brood infestation for population models and for the proportion of non sibling matings
    Journal of Apicultural Research, 1998
    Co-Authors: S E Reich, Stefan Fuchs, A Schulz, W Urfer

    Abstract:

    SUMMARYThe parasitic mite Varroa jacobsoni infests the Brood Cells of its host Apis mellifera and reproduces in them. The distribution of the mites in the Brood Cells is an important aspect of the parasite’s biology, with implications for the estimation of the bee Brood infestation and possible damage to the Brood, for models of the dynamics of population growth, and for the degree of outbreeding. We describe a method for estimating the distribution of varroa per cell, i.e. the percentages of Brood Cells with 0, 1, 2,…mites, by the geometric distribution. Three estimates are presented, each referring to a different sampling method. One is given in detail, the other two just mentioned. We found that the geometric distribution model is applicable to worker Brood as well as the usually more highly infested drone Brood, and results in a good fit of the natural distribution of varroa per cell. Based on this estimation, we provide a method to assess the degree of outbreeding by calculating the probabilities of …

  • non reproducing varroa jacobsoni oud in honey bee worker Cells status of mites or effect of Brood Cells
    Experimental and Applied Acarology, 1994
    Co-Authors: Stefan Fuchs

    Abstract:

    The parasitic mite Varroa jacobsoni Oud. reproduces in sealed honey bee Brood Cells. Within worker Cells a considerable fraction of the mites do not produce offspring. It is investigated whether variation in the ratio of Cells without reproduction is caused by properties of the worker Brood, or by the state of the mites entering Cells. Pieces of Brood comb were taken from colonies of 12 different bee lines and were placed simultaneously into highly infested colonies. Non-reproduction was independent of the origin of the Brood pieces, indicating a minor role of a variation due to different Brood origin. Between colonies used for infestation, however, it differed considerably. A comparison of the proportion of Cells without reproduction when infested by one Varroa mite or when infested by two or three Varroa mites showed, that non-reproduction was mainly related to the state of the mites entering Cells, and only to a minor degree to an influence of the Brood Cells. A high ratio of worker Cells without reproduction was consistently reported in bee lines which survive the disease without treatment, and a high level of non-reproduction is thus regarded to be a key factor in breeding bees for high Varroa tolerance. The current results indicate, that differences in this trait are only to a minor degree related to differences between bee lines in the ability of the bee Brood to induce oviposition. These differences seem rather to depend on other, unknown colony factors influencing the reproductive state of Varroa when they enter Cells for reproduction.

  • Choice in Varroa jacobsoni Oud. between honey bee drone or workerBrood Cells for reproduction
    Behavioral Ecology and Sociobiology, 1992
    Co-Authors: Stefan Fuchs

    Abstract:

    The parasitic mite Varroa jacobsoni Oud. reproduces in Brood Cells of Apis mellifera. Reproductive success (RS) is higher in drone Cells than in worker Cells. Although the mites are capable of discriminating between the cell types, the less favorable worker Cells are also parasitized. A model is proposed that explains the acceptance of worker Cells by density-dependent reduction of RS if more than one Varroa enters a Brood cell. Calculations were based on simulated distributions of Varroa on Brood combs. Assuming that mites infesting Brood Cells would always accept drone Cells, but would only sometimes accept worker Cells, the optimal rate of worker cell acceptance was determined. While at low infestation levels and high fractions of drone Cells selection would favor the parasitization of drone Brood Cells only, mixed strategies would result if infestation is high and/or drone Cells are scarce. The model calculations were applied to data on Brood cell availability in European colonies during one annual season, including seasonal shifts of selection intensity and direction. On average, accepting worker Cells would be advantageous when there are approximately 300 or more mites within a colony, which would be within the natural range of worker cell acceptance at densities of approximately 1000 Varroa mites per colony.