Reproductive soldiers of Zootermopsis nevadensis (Isoptera: Termopsidae): Morphology, development, behavior, and evolution

In primitive termites, most colony members retain developmental flexibility, with lifelong potential to differentiate into a replacement reproductive. Reproductive soldiers are a rare type of replacement reproductive, known only in the primitive family Termopsidae. Early-20th-century reports of reproductive soldiers in the relictual genus Archotermopsis were investigated in a new species in northern Thailand. In the lab, dissections and colony manipulations involving reproductive soldiers were performed with Zootermopsis nevadensis. Reproductive and normal soldiers can be distinguished by morphological characteristics such as head shape. Developmental pathways in Z. nevadensis were explored through removal of specific castes from individual colonies and observation of subsequent reproductive soldier differentiation. The evolution of reproductive soldiers is discussed in the contexts of ecological dynamics, intraspecific competition, and colony fitness.