Expression of Vitellogenin and Transferrin in Activated Ovaries of Worker Honey Bees, Apis mellifera

Abstract

The European honey bee (Apis mellifera L.; Hymenoptera: Apoidea) is a eusocial species within the insect order Hymenoptera. The female caste in each colony consists of several thousand sterile workers, with undeveloped and reduced ovaries, and a single reproductive queen. In addition, at certain limited times, males (drones) and additional queens are produced but rapidly leave the colony. A new virgin queen will typically make several mating flights, during which she will mate with 10–40 (average 12) drones (Tarpy and Nielsen 2002). After mating, the queen will activate her ovaries within a few days and start production of fertilized eggs. Such fertilized (diploid) eggs will normally develop as females, as either sterile workers or new queens with only 2–12 or up to 180 ovariole primordia (anlagens), respectively (Hartfelder and Steinbruck 1997; Capella and Hartfelder 1998), depending on the developing larval feeding regime and duration. However, if the sperm utilized was from a matched male with respect to the complementary sex determination system, the zygote develops as a diploid male instead (Evans et al. 2004). In the normal queenright condition, the queen and the broods secrete pheromones and substances to control her offspring and suppress the development of the remaining 2–12 primordial ovarioles in workers (Free 1987). Therefore, only a few workers (*0.01%) in a queenright colony have functionally active (developed) ovaries and are capable of laying unfertilized (haploid) eggs that will develop, if allowed by the colony, as uniparental sons (Page and Erickson 1988; Visscher 1989; Oldroyd and Osborne 1999). In contrast, in a queenless colony, the portion of unmated workers with fully active ovaries is markedly increased, with up