Hi All Just when you thought this one had gone away... I just got my hands on the 'Progress Report' (how it differs from an 'abstract' i don't know) for the research into small cell size underway here in NZ. No results yet mind, but this sets out the methodology. The research is apparently running behind schedule, as by the time the combs were drawn out, it was into winter weather here, and the bees weren't too interested in raising much brood. I hear that the drawn combs are waiting in the freezer for our spring to roll around... While i would have used a different methodology, these folk have great credentials, so i'll just sit quiet (you learn a thing or 2 as the years go by). There is also a part B planned should cell size prove effective against mites, to ensure there are no downsides to production, from using smaller bees. I expect 'normal' sized cells refers to comb built on typical 5.4 NZ foundation. I am however puzzled over someone's rounding-off efforts... FWIW. -Pav CAN THE REDUCTION OF CELL SIZE REDUCE THE IMPACT OF VARROA? M.A. Taylor and R.M Goodwin April, 2001 Sustainable Farming Quarterly Progress Report HortResearch Client Report No: 2001/291 Part A: Effect of cell size on the reproductive success of Varroa Destructor Introduction Varroa Destructor is a phoretic external parasite of worker and drone honey bees (Apis mellifera). Due to the recent introduction of this unwanted mite into New Zealand, international research is being reviewed to identify appropriate methods of mite control for New Zealand (Goodwin and Van Eaton, 2001). However, New Zealand's climatic conditions, flora and fauna, and unique beekeeping practices mean that much of the overseas experience is not directly transferable. Currently, miticides are used to control varroa world-wide. However, due to the development of resistance problems, coupled with the organic image of New Zealand honeys, these control methods may have a detrimental effect on both New Zealand's beekeeping practices and trade on the international market. International research suggests that cell size may reduce the reproductive rate of varroa (Message and Goncalves, 1995). If this is the case hive damage, resulting from varoosis, may be delayed, and the need for miticide use, reduced. The aim for this project is to determine whether a reduction in honey bee comb cell size will reduce the reproductive success of Varroa destuctor in New Zealand. Methods This trial is being conducted in an apiary run by HortResearch at the Ruakura Campus, East Street, Hamilton. The site was originally to be managed in Auckland but due to the recent finding of varroa within 2km of Hortresearch's Hamilton apiary the trial has been relocated for ease of use. Five different cell sizes, 4.7, 4.8, 5.0, 5.1 and 5.4mm have been selected for analysis. The 5.0 and 5.4mm foundation were sourced from New Zealand Beeswax Ltd, South Canterbury New Zealand, in late January 2001. The 4.7 foundation was sourced from South Africa, and the 4.8 and 4.9mm foundations were from the United States of America. All three international shipments were sent directly to Schering-Plough in Upper Hutt for irradiation treatment, and then forwarded to HortResearch, Ruakura Research Centre, in late February 2001. The ordered cell size varied slightly from the actual size (Table 1). Throughout this study the cell sizes will be referred to as the actual cell size (1 decimal place). Six sheets of each foundation were embedded in frames and placed in hives with large bee populations, for the cell walls to be drawn out. Twenty frames of normal foundation were also drawn out at the same time. The late arrival of foundation has resulted in autumn weather patterns effecting the colonies so that their populations have started to decline and the bees have focussed on collecting winter stores rather than the establishment of new storage areas. This means a delay in the time that the bees are taking to draw out the foundation and has delayed milestone completion. In an attempt to schedule each colony was fed sugar syrup every two days, to aid the foundation-drawing process, and then the undrawn foundation was shifted to where where a strong flow of rata nectar has lengthened the foraging season. Table 1. Actual versus ordered cell size of foundation Ordered cell size (mm) 4.8 4.9 4.9 5.0 5.4 Actual cell size (mm) 4.71 4.8 5.08 5.11 5.4 Country of Origin SA USA USA NZ NZ Ten nucleus colonies have been established using sister queens and varroa infested bees from Auckland. Until the five different sized foundations are fully drawn out and all mosiac frames constructed, the bees will be managed with two frames of normal sized brood cells and a feeder. As each of the full-depth fames, of the different cell sizes, 4.7, 4.8, 5.0, 5.1 and 5.4mm has been drawn out they have been removed from the colonies, frozen and then cool stored. Expected Progress Once all framesare drawn they will be cut into 5cm x 8cm sections and randomly inserted in the centre of the newly drawn, normal cell-size frames. These five sections of cell sizes, plus a control (normal cell size) section, will replace the normal cells in a 2x3 grid. Two of these mosiac frames, and a frame of bare foundation, will replace the brood frames in each of the 10 varroa infested nuc colonies. This limits the queen's egg laying space to the constructed frames. Once she starts to lay, 100 eggs from each of the six cell size sections will be marked using map pins. When the pupae in the six sections of cells are 19-20 days old the repructive sucess of varroa will be analysed. The brood comb will be removed and frozen to kill the mites. The sections will then be thawed, and the cells will be uncapped individually to identify the presence and number of adult females, deutomnymphs, and other offsring of Varroa, as outlined in Message and Goncalves (1995). This reproductive data will be collected and statistically analysed during the next quarter and used to identify whether any of the cell sizes reduce the reproductive rate of Varroa, and if so, which has the greatest impact. This cell size that produces the greatest impact (Part B) will then be assessed further to determine whether smaller sized cells result in smaller bees and lower production. References Goodwin, M and C. Van Eaton. 2001 Control of varroa - A guide for New Zealand Beekeepers. External report by HortResearch to Ministry of Agriculture and Forestry. Message, D and L.S. Goncalves. 1995. Effect of the size of worker brood cells of Africanised honey bees on infestation and reproduction of the ectoparasitic mite Varroa jacobsoni Oud. Apidologie 26:381-386 www.hortresearch.co.nz Head Office The Horticulture & Food Research Institute of NZ Ltd Batchelor Research Centre Private Bag 11030 Palmerston North Telephone: +64-6-356 8080 Facsimile: +64-6-354 0075 Ruakura Research Centre The Horticulture & Research Institute of NZ Ltd Private Bag 3123 Hamilton Telephone: +64-7-858 4728 Facsimile: +64-7-858 4704 ________________________________________________ (\ Pav [log in to unmask] {|||8- Ahaura, New Zealand (/ http://geocities.com/bombusmaximus/picpointer.html