Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies

We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honey bee (Apis mellifera cape nsis) workers. Workers often join neighboring colonies by drifting, but lon g-range drifting (dispersal) to colonies far away from the maternal nests a lso rarely occurs. We tested the impact of queenstate and taxon of mother a nd host colonies on drifting and dispersing of workers and on the hosting o f these workers in A. m. capensis, A. in. scutellata, and their natural hyb rids. Workers were paint-marked according to colony and reintroduced into t heir queenright or queenless mother colonies.,After 10 days, 579 out of 12, 034 labeled workers were recaptured in foreign colonies. We found that drif ting and dispersing represent different behaviors, which were differently a ffected by taxon and queenstate of both mother and host colonies. Hybrid wo rkers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequent ly than the hybrids. Dispersers from queenright A. m. capensis colonies wer e more often found in queenless host colonies and vice versa, indicating ac tive host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different host ing mechanisms of foreign workers by hybrid colonies may also be responsibl e for the stability of the natural hybrid zone between A. m. capensis and A . m. scutellata.