A NETWORK FOR EVALUATING HONEY BEE STOCKS FOR VARROA TOLERANCE IN ARGENTINA

ALGNASSE, A. ; AGRA, M.; BEDASCARRASBURE, E; CAMACHO, M.B; CLADERA, J; CORVA, P.; FIGINI, E.E.; FOURQUET, G; GARCIA, S.; HUERTA, G; LANZAVECCHIA, S.B; MALDONADO, M.E.; MARTÍNEZ, A; MERKE, J; PALACIO, M.A; MILLA F.; PARREÑO, M.A.; POFFER, D; SCANNAPIECO, A.C; RODRIGUEZ, G.; SEGURA, D

Congreso; APIMONDIA; 2011

Selective breeding of honey bees stocks tolerant to varroosis is one of the most important challenges to keep Varroa destructor populations in a low level without the use of chemical control. In Argentina many honeybee subspecies have been introduced and they have overcrossed and adapted to different environments. A network for evaluating these honeybee populations for varroa tolerance has been created. The interaction between genetic and environment must be considered whenever honeybee stocks are evaluated. So, seven evaluation centres (EC) have been installed in different regions of the country with different environmental conditions: subtropical, temperate and cold climates. Local stocks (LS) which have not received acaricides in recent years and commercial stocks selected by hygienic behaviour (HBS) are been included in each EC. . Variables related to varroa population dynamic (phoretic varroa, varroa in brood cells, falling mites on hive bottom, parameters of varroa reproduction) and with honey bee population growth (adult bee, brood cells, reserves) are registered periodically. Hygienic behaviour and grooming are also evaluated. Colonies are characterized using mitochondrial markers and microsatellites. Colonies with lower varroa population that survive are selected through queen rearing and drone production. Control crosses using instrumental insemination are performed. The colonies selected in the EC are of different origins (LS or HBS) In one of the EC, four generations without the use of acaricides was obtained from a HBS. Daughter queens are evaluated in another EC. In order to investigate the genetic bases of varroa tolerance an analysis of candidate genes will be performed on the selected stocks. Volatile compounds associated with Varroa in cell-infestation that are used by honeybees as cues to target the removal of the mites or the infested brood will be identified and bees from selected stocks will be evaluated with these compounds.