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Non-removal behaviour This removal behaviour is shown much less in Apis cerana’s Varroa-infested drone brood cells. Perhaps worker bees are hindered from
uncapping mite-infested drone cells because of the unique, thick cocoon capping of Apis cerana drone cells. Maybe this allows Varroa to reproduce in only drone brood. But in the case of multiple-infested drone brood cells (more than two invaded mother mites per cell) the parasitised drones are weakened and they are not able to open the cell capping from the inside.
Varroa Trap Adult worker bees also do not open these highly-infested drone cells from the outside, the parasitised drones have to die together with the whole number of infesting mites in the cell. We can describe this as a natural “Varroa-trap” (Figure 2). This non-removal behaviour of Apis cerana towards multipleinfested drone cells is sometimes also supplemented by the worker bees plugging the central pore with wax material from outside (Figure 2A). This plugging of the central pore in Apis cerana drone cells by the worker bees can also be seen during infestation with European foulbrood, isolating this pathogen within the brood nest (Figure 2B). If the colony now absconds, many pathogens are left behind in the old nest, isolated in the non-removed and plugged cells.
Grooming behaviour Another known defence behaviour of Apis cerana that keeps Varroa in check is the bees’ grooming behaviour towards mites (Figure 3). Sometimes worker bees realise that mites are hiding on them. They try to get rid of them by self-grooming. If they fail to remove the mites they ask for help from nestmates using a specific shaking dance. Self- and nestmate-grooming leads to a disturbance and sometimes killing of the mites by the bees. The distinct phoretic positions preferred by the Varroa mites on the bodies of the bees show some adaptation towards escape from the grooming behaviour of the bees. During evolution Apis cerana bees have developed a complex of these defence behaviours to keep Varroa in check. “How clever they are!” Varroa jacobsoni has only recently been spread into populations of Apis mellifera bees that fail to keep Varroa in check. This is because the
defence behaviours present in Apis cerana exist to only a small extent in Apis mellifera, and its reproduction system is highly favourable for the Varroa mite to build large
A Bees for Development publication
LOOK AHEAD AUSTRALIA International Union for the Study of Social Insects 29 December 1998 - 4 January 1999, Adelaide Further information from: Dr M P Schwarz,
Flinders University, GPO Box 2100, Adelaide, Australia
BRAZIL
Xi Brazilian Apiculture Congress 10-13 November 1998, Bahia Further information from: Secretaria,
INTERLINK, Rua Teixeira Leal, 107-A, Graga, CEP 40150-050 Salvador, Bahia, Brazil Fax (+71) 336 5633 E-mail interlink@e-net.com.br
CANADA Apimondia International Apicultural Congress 12-18 September 1999, Vancouver Further details from: Apimondia 99, c/o
Venue West Conference Services, #645 - 375 Water Street, Vancouver, BC V6B 5CB, Canada Fax (+604) 681 2503 E-mail congress@venuewest.com
CHILE Sustainable Management of Forest Resources: Challenge of the 21st Century 22-28 November 1998, Valdivia Further details from: Secretaria de CONAF, Avenida Bulnes 286 6e piso, Valdivia, Chile Fax (+56) 2697 2273 E-mail dejecuti@iusanet.cl
INDIA Fifth International Congress International Society for Ethnopharmacology: Plant Derived Drugs in the 21st Century 8-12 February 1999, Thiruvananthapuram Further details from: Dr V George, Tropical Botanic Garden & Research Institute, Pacha Palode PO, Thiruvananthapuram, 695 562 Kerala, India Fax (+91) 471 431 178
ISRAEL XIV International Plant Protection Congress 25-30 July 1999, Jerusalem Further details from: Congress Secretariat,
XIV International Plant Protection
Congress, PO Box 50006, Tel Aviv 61500, Israel Fax (+972) 3514 0077
SOUTH AFRICA North Transvaal Beekeepers’ Association 60th Jubilee Symposium Beekeeping for Profit 30 September - 2 October 1998, Pretoria Further details from: NTBA Jubilee
Symposium, PO Box 29490, Sunnyside, Pretoria 0132, South Africa
THAILAND Fifth Asian Apicultural Association Conference 19-25 March 2000, Chiang Mai Further details from: Asian Apicultural
Association, c/o Honeybee Science Research Center, Tamagawa University, Machida Shi, Tokyo 194-8610, Japan Fax (+81) 427 39 8854 E-mail hitomi@agr.tamagawa.ac.jp
TOBAGO Caribbean Beekeeping Congress 17-20 November 1998 Further details from: Caribbean
Beekeeping Congress, c/o Technical Support Unit, Level 2, NIB Mall, Scarborough, Tobago, Republic of Trinidad and Tobago, West Indies Fax (+868) 639 4464 E-mail caribees@tstt.net.tt
UNITED KINGDOM National Honey Show 25-28 November 1998, London
Visit the:
a
at
“
Development
Further details from:
stand here— Rev F Capener, Baldric Close, Folkestone, Kent CT20 2NR, United Kingdom Tel/Fax (+44) 1303 254 579 E-mail nathon@amigabee.org.uk 1
LEARN AHEAD
BRAZIL Courses in Spanish, Centro de Apicultura Tropical 19-23 October 1998 Beekeeping management 9-13 November 1998 Wax technology and analysis 23-27 November 1998 Queen rearing Further details from: Centro de Apicultura Tropical, Avenida Manuel César Ribeiro, 1920 Caixa Postal 176, 12400-970 Pindamonhangaba SP, Brazil E-mail ethel@iconet.com.br We can print notice of your meeting or workshop in Look Ahead or Learn Ahead if you send details well in advance to
Bees for Development, at
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