Storage proteins in adult ants (Camponotus festinatus): Roles in colony founding by queens and in larval rearing by workers

Camponotus festinatus storage hexamers (Hex 1 and 2), first identified in last instar larvae, constitute two major proteins in adult queens and broodless workers. We have examined the effects of colony founding by queens and larval rearing by workers on their storage protein content. Both hexamerins accumulate in virgin queens, particularly Hex 2 in the fat body where it makes up about 70% of total soluble proteins. Colony founding causes a depletion of Hex 1 and 2 in queens. Levels of these proteins begin to decrease by the end of the claustral period when the first workers emerge, and they are depleted from fat body and hemolymph 1 month later. Larval rearing has an inhibitory effect on the accumulation of storage proteins in workers. Hex 1 occurs only in low concentrations in the hemolymph of 2- and 4-week-old workers kept with larvae, and disappears thereafter. Hex 2 does not accumulate in 2- to 8-week-old workers kept with larvae. Our results with Camponotus queens support a role of the storage hexamers in egg development and/or nourishment of the brood. These data also suggest an important role of nutrition in the synthesis and accumulation of hexamerins in adult workers.