ROLE OF GUARD HONEY-BEES (HYMENOPTERA, APIDAE) IN NESTMATE DISCRIMINATION AND REPLACEMENT OF REMOVED GUARDS

Guard honey bees, Apis mellifera L., patrol the colony entrance and have been hypothesized to exclude non-nestmate bees. We tested this hypothesis by comparing the expression of nestmate discrimination by different types of bees in colonies. Guard bees are significantly more likely to bite or sting a foreign bee than other task groups (nurses, undertakers, soldiers, pollen foragers, and liquid foragers). We also hypothesized that guarding and undertaking could be overlapping responsibilities; each involves the removal of bees from the colony. Undertakers and guards do not perform the same activities. Finally, guards may be injured or killed in encounters with foreign bees; as a result they must be replaced by the colony. The control rate of appearance of new guards was 2.8 new guards per hour, but when most of the guards were removed this rate became significantly higher (4.9 per hour).