Maternity of replacement queens in the thelytokous Cape honey bee Apis mellifera capensis

Abstract

Unlike workers of all other honey bee (Apis mellifera) subspecies, workers of the Cape honey bee of South Africa (A. mellifera capensis) reproduce thelytokously and are thus able to produce female offspring that are pseudoclones of themselves. This ability allows workers to compete with their queen over the maternity of daughter queens and, in one extreme case, has led to a clonal lineage of workers becoming a social parasite in commercially managed populations of A. mellifera scutellata. Previous work (Jordan et al., Proc R Soc Lond B Biol Sci 275:345, 2008) showed that, in A. mellifera capensis, 59% of queen cells produced during swarming events contained the offspring of workers and that, of these, 65% were the offspring of non-natal workers. Here, we confirm that a substantial proportion (38.5%) of offspring queens is worker-laid. We additionally show that: (1) Although queens produce most diploid female offspring sexually, we found some homozygous or hemizygous queen offspring, suggesting that queens also reproduce by thelytoky. These parthenogenetic individuals are probably nonviable beyond the larval stage. (2) Worker-laid offspring queens are viable and become the resident queen at the same frequency as do sexually produced queen-laid offspring queens. (3) In this study, all but one of the worker-derived queens were laid by natal workers rather than workers from another nest. This suggests that the very high rates of social parasitism observed in our previous study were enhanced by beekeeping manipulations, which increased movement of parasites between colonies.