Nymph–soldier intercastes in Nasutitermes lujae and N. columbicus (Isoptera; Termitidae)

Observations of nymph–soldier intercastes are rare among the higher termites (Termitidae), and are here described from Nasutitermes lujae and N. columbicus. Morphological and histological observations indicate that N. lujae intercastes are derived from small workers, as are normal soldiers. Nasutitermes columbicus intercastes, however, develop from alate nymphs. The presence of exceptional intercastes in higher termites is evidence of postembryonic influences on caste determination and differentiation.