Evaluation of the time of uncapping and removing dead brood from cells by hygienic and non-hygienic honey bees

Most research on hygienic behavior has recorded the time taken by the colony to remove an experimental amount of dead brood, usually after one or two days. We evaluated the time that hygienic (H) and non-hygienic (NH) honey bees take to uncap and remove dead brood in observation hives after the brood was killed using the pin-killing assay. Four experimental colonies were selected as the extreme cases among 108 original colonies. Thirty brood cells were perforated with a pin in two H and two NH colonies and observations were made after 1, 2, 3, 4, 5, 6, and 24 h. Different stages of uncapping and removing were recorded. Differences in uncapping and removal between H and NH colonies were significant for all comparisons made at the different times after perforation. Using observation hives one obtains a better and faster discrimination between H and NH colonies than in full size colonies. It is possible to differentiate H and NH within a few hours after perforating the cells.