The Rate of Regeneration in the German Roach

Abstract

Regeneration, the ability to replace lost or injured appendages, is commonly acknowledged as being spread widely throughout the insect world, but specific citations are surprisingly meagre. Even those which are available are mostly mere records of occurrence, while the majority of the fundamental research in this connection has dealt with the Crustacea. Woodruff (1937) attempted to summarize the entomological literature and recorded observations on the German roach. This species, Blattella germanica (L.), was found to have two well defined breaking-points on each leg; one at the tibio-tarsal joint and the second between the trochanter and femur. Regeneration, as in all arthropods, occurred only at the time of ecdysis, normally at the first following the amputation, but even when a leg was removed immediately after eclosion the new growth was occasionally retarded through the succeeding stadium. Regenerated appendages frequently equalled the normal by the time adulthood was reached, except for the fact that renewed tarsi were always composed of only four subsegments in place of the usual five. Multiple fractures being repaired simultaneously appeared to proceed at approximately the same rate, but otherwise had no influence upon each other; at least, there was no perceptible decrease in rate.