Abating feral Africanized honey bees (Apis mellifera L) to enhance mating control of European queens

Abatement of local feral honey-bee colonies was tested as a method to increase the mating control of European queens produced in an Africanized area. Feral colonies within 2 km of a commercial mating apiary at Belén, Guanacaste Province, Costa Rica were targeted. Thirty-eight feral colonies were discovered in the 12.5-km2 study plot between 13 May and 6 June 1992. Abatement techniques included dispensing avermectin-ivermectin paste (applied manually to the abdominal tergites of drones captured during mating flights) and acephate-treated sucrose syrup bait (retrieved by foragers), and spraying nests directly with pyrethroids. Twenty-one of the known colonies were killed or severely weakened by treatments made between 27 May and 5 June. Mating control in pre-abatement (n = 27) and post-abatement (n = 26) queens was estimated by measuring changes in morphology and in frequencies of allozymes (malate dehydrogenase-1100 and hexokinase-1100) of worker progeny relative to reference populations of workers from local Africanized (n = 35) and imported European (n =23) colonies. Five of 23 morphological features shifted significantly toward the European form after abatement. Significantly more post-abatement colonies (85%) than pre-abatement colonies (63%) were classified by multivariate discriminant analysis as European (ie with a probability of Africanization of < 50%). Paternal frequencies of both allozymes were shifted significantly toward European frequencies following abatement; malate dehydrogenase decreased 26% and hexokinase increased 43%. Overall the results suggest that abatement may be useful in augmenting other mating control methods (eg, drone flooding and controlling mating times) but that it is probably not feasible as a unilateral approach to achieving acceptable mating control in heavily Africanized areas