Expansion of presoldier cuticle contributes to head elongation during soldier differentiation in termites

In termites, the soldier caste possesses morphological features suitable for colony defence, despite some exceptions. Soldiers are differentiated via two moultings through a presoldier stage with dramatic morphogenesis. While a number of morphological modifications are known to occur during the presoldier moult, growth and morphogenesis seem to continue even after the moult. The present study, using the damp-wood termite Hodotermopsis sjostedti, carried out morphological and histological investigations on the developmental processes during the presoldier stage that is artificially induced by the application of a juvenile hormone analogue. Measurements of five body parameters indicated that head length significantly increased during the 14-day period after the presoldier moult, while it did not increase subsequently to the stationary moult (pseudergate moult as control). Histological observations also showed that the cuticular development played a role in the presoldier head elongation, suggesting that the soft and flexible presoldier cuticle contributed to the soldier morphogenesis in termites

Structure and function of defensive glands in soldiers of Glossotermes oculatus (Isoptera: Serritermitidae)

The soldier caste represents the most conspicuous realization of termite eusociality, characterized by an extreme anatomical, behavioural, and physiological specialization. Numerous strategies have evolved in soldiers, including extreme adaptations such as self-sacrifice by autothysis. In the present study, we investigated the structure and function of defensive glands in Glossotermes oculatus soldiers aiming to understand their use in combat. Three glands are involved in defence: labral, frontal, and labial glands. Mandibles are used to bite the enemy, whereas the secretions of labral and labial glands are discharged into the wound. A striking characteristic of G. oculatus is the lack of the frontal pore; the secretion of the frontal gland is discharged by a rupture of the body wall. We hypothesized that this self-sacrifice is an efficient way of blocking a gallery under attack. A similar development of the frontal gland occurs in Serritermes serrifer, which supports the close relationship between the two genera inferred from morphological and genetic analyses. © 2010 The Linnean Society of London.SCOPUS: ar.jinfo:eu-repo/semantics/publishe