HORMONAL-STIMULATION AND INVITRO CELLULAR-DIFFERENTIATION IN THE INTEGUMENT OF THE DESERT LOCUST SCHISTOCERCA-GREGARIA

  • 1 January 1979
    • journal article
    • research article
    • Vol. 68  (2) , 127-138
Abstract
Spontaneous cellular differentiation (glandular units appearance with a well-defined duct) is observed in larval integument of S. gregaria cultured in a hormone-free medium. Hormonal stimulations modify the expression of this phenomenon, particularly the frequency of new elaborated duct cells of the secretory units. The most effective factor is supplied by the prothoracic glands. Complete secretory units can be observed but the glandular cells are in an undifferentiated and nonfunctional state. They appear active if the corpora allata act after the prothoracic glands. Corpora allata alone or synthetic juvenile hormones have an inhibitory effect. The addition of .alpha.-ecdysone permits only cellular divisions, a preliminary and indispensable condition for exterior differentiation. Between cuticles deposited with .beta.-ecdysone, newly formed ducts occur in the theoretical imaginal exuvia. The elaboration and the activity of imaginal glandular units are conditioned by the larval hormonal context; by contrast, sex dimorphism is only a genetic process.