Endocrine control of caste differentiation in Zootermopsis angusticollis Hagen (Isoptera)

The effect of injection of Röller's juvenile hormone (JH) or farnesyl methyl ether (FME) on differentiation of supplementary reproductives and presoldiers of Zootermopsis angusticollis has been studied. Early in the stadium (that is, during the competence period) Röller's JH and FME inhibit differentiation. When injected after the competence period the substances do not alter the rate of supplementary reproductive differentiation in orphaned colonies but enhance presoldier differentiation in soldierless colonies provided that there is a sufficient number of supplementary reproductives present.A modified version of Lüscher's (1960) hypothesis for the endocrine control of caste differentiation is proposed. It is suggested that all the developmental possibilities that exist in the termite colony can be explained on the basis of a single corpus allatum hormone produced in different quantities and at different times within the stadium.