Oxygen Consumption During Hovering is Associated with Genetic Variation of Enzymes in Honey-Bees

Despite a general paucity of genetic variation, colonies of honey-bees, Apis mellifera L., usually contain genetic variation for the soluble form of the enzyme malate dehydrogenase (s-MDH). To determine whether this genetic variation influenced the physiology of honey-bees, we examined the maximal metabolic rate (V02max) during hovering flight of the common s-MDH genotypes. Among workers, heterozygotes and slow homozygotes had similar, low V02maxs and the fast homozygote had the highest. In drones, the pattern was reversed: the V02max of the slow haplotype exceeded that of the fast haplotype. In both males and females, the variances of V02max were heteroscedastic among s-MDH genotypes and the genotype with the highest V02max also had the highest variance. The data suggest that there may be kinetic differences among s-MDH allozymes. Drones had significantly higher thoracic temperatures than workers. The reversal of favoured genotypes in workers and drones may be related to the difference in thoracic temperature between