The influence of juvenile hormone analogue on soldier differentiation in the higher termite,Macrotermes michaelseni*

ABSTRACT. The influence of topically-applied or vapour-administered juvenile hormone analogue (ZR-515, methoprene (JHA)), on soldier differentiation in a higher termite species, Macrotermes michaelseni (Sjostedt) (Isoptera; Macro-termitinae) was examined. It was found that even male third larvae, which under natural conditions develop exclusively into major workers, could be induced by JHA to differentiate into presoldiers. Intermediate forms between workers and soldiers were produced from some of the treated individuals. Administered in vapour form, JHA induced a higher proportion of presoldiers and a lower proportion of intermediate forms than it did when administered topically. The rate of presoldier formation was found to be JHA-dose-dependent. Biometric analysis showed that male presoldiers have the largest head capsule size, but the smallest mandibular index. The possible mechanism of soldier induction is discussed.