Browsing by Subject "hygienic behaviour"

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    Facultative expression of hygienic behaviour of honey bees in relation to disease resistance
    (Taylor and Francis, 1993) Spivak, Marla; Gilliam, Martha
    Four experiments were conducted to examine factors that influence the expression of hygienic and non-hygienic behaviour in honey bees, Apis mel/itera, and to examine the correlation between this behaviour and resistance to chalkbrood, Ascosphaera apis. Colonies were headed by instrumentally inseminated queens selected on the basis of uncapping and removal behaviour expressed by their progeny. In the first experiment, colony strength was altered by transferring hygienic and nonhygienic colonies from 1O-frame field hives to 2-frame observation hives. This treatment significantly reduced the hygienic response of the hygienic bees but did not affect the response of the non-hygienic bees. In the second experiment, hygienic and non-hygienic bees displayed different responses to freeze-killed and live brood which had been partially or entirely uncapped. Both lines of bees recapped both partially and entirely uncapped live brood, but non-hygienic bees also recapped partially uncapped freeze-killed brood, suggesting that non-hygienic bees either could not detect dead or diseased brood or avoided it by sealing it within a comb cell. The third experiment tested whether the degree of hygienic behaviour could be increased by adding hygienic bees to non-hygienic colonies. Adding 20-30% young hygienic bees to nonhygienic colonies did not increase the degree of hygienic behaviour, but adding young nonhygienic bees to hygienic colonies suppressed the behaviour. The results suggest that although hygienic behavior is genetically determined, its expression depends on colony strength and composition of workers within the colony. In the fourth experiment, the hygienic and non-hygienic colonies were fed with pollen patties containing A. apis spores. The weak correspondence that was observed between removal behaviour and physiological resistance to chalkbrood suggested that few colonies are both highly hygienic and physiologically resistant to chalkbrood. Selection against uncapping and removing diseased brood might occur if this behaviour also promotes the spread of disease through the colony. This possibility is discussed in relation to avoidance behaviour of other social insects toward pathogens.
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    Hygienic behaviors of honey bees in response to brood experimentally pin-killed or infected with Ascosphaera apis
    (2010) Palacio, María Alejandra; Rodriguez, Edgardo; Goncalves, Lionel; Bedascarrasbure, Enrique; Spivak, Marla
    Hygienic behavior of honeybees involves inspection, uncapping and removal of diseased and dead brood from the colony. The objective of this work was to study the activities involved in hygienic behavior of individually tagged bees from selected hygienic (H) and non-hygienic (NH) colonies in the presence of chalkbrood infected brood (Ascosphaera apis) or pin-killed brood. No significant difference was detected in the age of bees inspecting, uncapping or removing brood in H and NH colonies; the median age was 15 days for all activities. The percentage of bees that performed these activities was significantly higher in H colonies. In NH colonies the bees that performed this behavior were more persistent but bees in H colonies were more efficient in the removal of the chalkbrood mummies. H colonies began uncapping more rapidly in response to the stimulus of dead brood independent of the method used to kill it. H and NH bees took the same amount of time to remove the mummies once they initiated the uncapping process but NH colonies took longer to remove pin-killed brood. These findings confirm previous behavioral studies on the activities of hygienic and non-hygienic bees toward freeze-killed brood, but this is the first time the entire process from inspection to removal was focused on individual cells containing actual diseased brood.