Juvenile hormone paces behavioral development in the adult worker honey bee

Behavioral development in the adult worker honey bee (Apis mellifera), from performing tasks inside the hive to foraging, is associated with an increa se in the blood titer of juvenile hormone III (JH), and hormone treatment r esults in precocious foraging. To study behavioral development in the absen ce of JH we removed its glandular source, the corpora allata, in 1-day-old adult bees. The age at onset of foraging for allatectomized bees in typical colonies was significantly older compared with that of sham-operated bees in 3 out of 4 colonies; this delay was eliminated by hormone replacement in 3 out of 3 colonies. To determine the effects of corpora allata removal on sensitivity to changes in conditions that influence the rate of behavioral development, we used "single-cohort" colonies (composed of only young bees ) in which some colony members initiate foraging precociously. The age at o nset of foraging for allatectomized bees was significantly older compared w ith that of sham-operated bees in 2 out of 3 colonies, and this delay was e liminated by hormone replacement. Allatectomized bees initiated foraging at significantly younger ages in single-cohort colonies than in typical colon ies. These results demonstrate that JH influences the pace of behavioral de velopment in honey bees, but is not essential for either foraging or alteri ng behavioral development in response to changes in conditions. (C) 2000 Ac ademic Press.