Storage function and ultrastructure of the adult fat body in workers of the ant Camponotus festinatus (Buckley) (Hymenoptera: Formicidae)

The presence of storage proteins in ants is perhaps most remarkable in its abundance in some species in the adult stage. The ultrastructure of fat body in workers of Camponotus festinatus (Hymenoptera : Formicidae) confirms that they do indeed store large quantities of protein, as well as lipid and carbohydrate, under some conditions. Rounded electron-dense granules, which are abundant in workers maintained in groups isolated from the parent colony, probably contain an arylphorin-like protein. Irregularly shaped electron-dense granules present in all workers regardless of age, caste or social environment, resemble primarily lysosomes, but lack acid phosphatase activity. Peroxisomes were also identified but were not associated with either type of dense granule. Lipid analysis showed that lipid storage followed similar patterns to protein storage, with isolated workers, especially soldiers, accumulating huge quantities of triglycerides. The relationship between storage of nutrient reserves and the presence of larvae suggests that the stores may function in regulating seasonal brood production.