Maternity of emergency queens in the Cape honey bee, Apis mellifera capensis

During reproductive swarming, some workers of the Cape honey bee, Apis mellifera capensis, lay eggs in queen cells, many of which are reared to maturity. However, it is unknown if workers are able to lay in queen cells immediately after queen loss during an episode of emergency queen rearing. In this study we experimentally de-queened colonies and determined the maternity of larvae and pupae that were reared as queens. This allowed us to determine how soon after queen loss workers contribute to the production of new queens. We were further interested to see if workers would preferentially raise new queens from queen-laid brood if this was introduced later. We performed our manipulations in two different settings: an apiary setting where colonies were situated close together and a more natural situation in which the colonies were well separated. This allowed us to determine how the vicinity of other colonies affects the presence of parasites. We found that workers do indeed contribute to queen cell production immediately after the loss of their queen, thus demonstrating that some workers either have activated ovaries even when their colony has a queen or are able to activate their ovaries extremely rapidly. Queen-laid brood introduced days after queen loss was ignored, showing that workers do not prefer to raise new queens from queen brood when given a choice. We also detected non-natal parasitism of queen cells in both settings. We therefore conclude that some A. m. capensis genotypes specialize in parasitizing queen cells.Centre of Excellence for Invasion Biolog

Androgenesis: where males hijack eggs to clone themselves.

Androgenesis is a form of quasi-sexual reproduction in which a male is the sole source of the nuclear genetic material in the embryo. Two types of androgenesis occur in nature. Under the first type, females produce eggs without a nucleus and the embryo develops from the male gamete following fertilization. Evolution of this type of androgenesis is poorly understood as the parent responsible for androgenesis (the mother) gains no benefit from it. Ultimate factors driving the evolution of the second type of androgenesis are better understood. In this case, a zygote is formed between a male and a female gamete, but the female genome is eliminated. When rare, androgenesis with genome elimination is favoured because an androgenesis-determining allele has twice the reproductive success of an allele that determines sexual reproduction. Paradoxically, except in hermaphrodites, a successful androgenetic strain can drive such a male-biased sex ratio that the population goes extinct. This likely explains why androgenesis with genome elimination appears to be rarer than androgenesis via non-nucleate eggs, although both forms are either very rare or remain largely undetected in nature. Nonetheless, some highly invasive species including ants and freshwater clams are androgenetic, for reasons that are largely unexplained.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'

Effects of additional caged and free-running queens on honey bee (Apis mellifera) colony performance

Colonies were established containing the following combinations of queens : 1 free-running queen, 2 free-running queens, 1 free-running queen and 1 caged queen, and 1 free-running queen and 4 caged queens. Brood area and colony weight gain were measured for each treatment. Colonies with 1 queen had the highest colony weight gain. The presence of additional queens in colonies had several negative effects on performance. Mortality of free-running queens was increased by the presence of 1 caged queen, which caused a reduction in brood area and colony weight gain. There was no significant difference in the brood production of single queen colonies, and colonies containing 2 free-running queens. The results do not support the use of caged queens or 2-queen colonies for increasing honey production

On the relative importance of queens and workers to honey production

Colonies of honey bees (Apis mellifera) with different queen genotypes, but identical worker genotype, were established. The 2 groups differed significantly in both weight gain and brood area, indicating that queen genotype influences honey production. In a second experiment, 2 groups of genetically similar queens were inseminated with genetically dissimilar semen. The sire groups did not differ significantly in their honey production over a period of 3 months. It is concluded that queen genotype plays a significant part in colony genotypic merit for honey production, and that selection schemes which do not evaluate queen performance are likely to be only partially successful

Unequal thermostability of allelic forms of malate dehydrogenase in honey bees

International audienc

Mitochondrial DNA variation in Moroccan and Spanish honey bee populations

International audienc

Genetic control of the honey bee (Apis mellifera) dance language: segregating dance forms in a backcrossed colony

We studied the genetic control of the dance dialects that exist in the different subspecies of honey bees (Apis mellifera) by observing the variation in dance form observed in a backcross between two lines that showed widely different dance dialects. To do this we generated the reciprocal of the cross performed by Rinderer and Beaman (1995), thus producing phenotypic segregation of dance forms within a single colony rather than between colonies. Our results are consistent with Rinderer and Beaman (1995) in that inheritance of the transition point from round dancing → waggle dancing is consistent with control by a single locus with more than one allele. That is, we found one dance type to be dominant in the F1, and observed a 1:1 segregation of dance in a backcross involving the F1 and the recessive parent. However, we found some minor differences in dance dialect inheritance, with the most significant being an apparent reversal of dominance between our cross (for us “black” is the dominant dialect) and that of Rinderer and Beaman (1995) (they report “yellow” to be the dominant dialect). We also found that our black bees do not perform a distinct sickle dance, whereas the black bees used by Rinderer and Beaman (1995) did perform such a dance. However, our difference in dominance need not contradict the results of Rinderer and Beaman (1995), as there is no evidence that body color and dominance for dance dialect are linked

Factors affecting the dynamics of the honeybee (Apis mellifera) hybrid zone of South Africa

Hybrid zones are found wherever two populations distinguishable on the basis of heritable characters overlap spatially and temporally and hybridization occurs. If hybrids have lower fitness than the parental types a tension zone may emerge, in which there is a barrier to gene flow between the two parental populations. Here we discuss a hybrid zone between two honeybee subspecies, Apis mellifera capensis and A. m. scutellata and argue that this zone is an example of a tension zone. This tension zone is particularly interesting because A. m. capensis can be a lethal social parasite of A. m. scutellata. However, despite its parasitic potential, A. m. capensis appears to be unable to increase its natural range unassisted. We propose three interlinked mechanisms that could maintain the South African honeybee hybrid zone: (1) low fitness of intercrossed and genetically mixed colonies arising from inadequate regulation of worker reproduction; (2) higher reproductive success of A. m. scutellata via both high dispersal rates into the hybrid zone and increased competitiveness of males, countered by (3) the parasitic nature of A. m. capensis.Centre of Excellence for Invasion Biolog