VOLATILE COMPOUNDS FROM V. DESTRUCTOR-INFESTED PUPAE ELICITED HYGIENE BEHAVIOR IN A. MELLIFERA WORKERS

LIENDO, MARÍA CLARA; FERNANDEZ PC; RUSSO R; MUNTAABSKI I; LANZAVECCHIA SB; CLADERA JL; PALACIO MA; SCANNAPIECO AC

Congreso; 1º Joint Meeting ISCE/ALAEQ; 2016

The mite Varroa destructor is the most destructive parasite of the honeybee Apis mellifera. From larva to emergence of the developing bee, the mite and her offspring feed on the haemolymph of the host. A. mellifera displays a social immunity mechanism against brood diseases that consists in detect, uncap and remove dead or diseased brood from the hive (hygienic behavior). Previous studies showed that chemical cues could be involved in the detection of diseased brood by worker bees and hence in triggering hygienic behavior. The aim of this research was to study the chemical stimuli that induce hygienic behavior of worker bees, exploring the volatile compounds associated with cuticle of mite-infested pupae and cell?s wax cap. Newly-capped bee brood was artificially infested with one mite. Ten days later, 15 pupae were removed from the combs and mite presence and reproductive status were confirmed (infested group). Non-infested pupae were simultaneously removed (control group). Volatile compounds were obtained by washing the pupae from each group with dichloromethane. Small filter papers that were saturated with each extract were introduced in 25 cells containing recently capped uninfected brood. In parallel, the wax caps from each group were transferred to uninfected-brood cells. For both experiments, the number of removed pupae was recorded and eco-chemical profiles were evaluated. Worker bees removed higher percentages of brood with infested pupae extract than with control pupae extract. No differences were found in percentage of removed brood from infested vs control wax cap cells. For both experiments chemical profiles were different between groups. The present results suggest differences in cuticle volatile compound between healthy and infested pupae could act as a signal for triggering hygienic behavior. This information contributes to a better understanding of this social mechanism against the mite and provides tools to the selection of Varroa-tolerant colonies