Regeneration and the Moulting Cycle in Blattella Germanica L. I. Single Regeneration Initiated During the First Instar

Abstract

The effects of removal of the left metathoracic leg of Blattella germanica at the proximal autotomy plane, i.e., between trochanter and femur, are descr. from operations on animals at known ages in the 1st instar, at temps, of 26 and 30[degree]C, 70 80% R. H. Either a completely differentiated regenerate or an undifferentiated papilla, but never an intermediate, appears at the 1st moult after operation. Where a papilla is produced, the complete regenerate appears at the 2d moult after operation. Ecdysis is not delayed by production of a papilla, but is delayed by production of a complete regenerate. The interval between the operation and the first moult then approximates to the duration of the 1st instar of controls, being greater with operations very early in the instar and less with later ones. There is a "critical period" in the 1st instar, before which operation gives rise to a regenerate with delay in the 1st ecdysis, and after which it results in production of a papilla without delay in ecdysis. Delay in the 1st ecdysis resulting from regeneration appears to be compensated by a subsequent speeding up of the moulting cycle, the ages of operated animals at their 4th ecdysis being approx. the same as those of controls. Hypotheses are discussed relating these results to endocrine control of the interaction between regeneration and the moulting cycle. The possibility of using regenerating Blattella germanica in exptl. work on moulting and metamorphosis is suggested.