Physiological and molecular mechanisms of insect appendage regeneration

Abstract

Regeneration, as a fascinating scientific field, refers to the ability of animals replacing lost tissue or body parts. Many metazoan organisms have been reported with the regeneration phenomena, but showing evolutionarily variable abilities. As the most diverse metazoan taxon, hundreds of insects show strong appendage regeneration ability. The regeneration process and ability are dependent on many factors, including macroscopic physiological conditions and microscopic molecular mechanisms. This article reviews research progress on the physiological conditions and internal underlying mechanisms controlling appendage regeneration in insects.

Keywords: Appendage regeneration; Epigenetics; Insects; Molecular mechanism; Physiological condition; Signaling pathways.

Fig. 1

Diagram of appendage regeneration in insects. Following injury or amputation, appendage regeneration in nymphal legs (A and B) or larval imaginal discs (C) proceeds through a generally similar process involving three stages: wound healing, blastema formation, and morphogenesis (regenerative growth, differentiation, and patterning). A In some Blattaria and other orders of insects, when amputation is performed at a site proximal to the femur, a new leg can be regenerated under the exoskeleton after one molt. B In some insects of the order Orthoptera, regeneration mainly occurs at the distal site of the tibia. Four molting cycles are needed for the successful regeneration of missing tissue. C After the surgical amputation of the imaginal leg disc, the smaller fragment from the anterior dorsal quadrant regenerates the remainder of the disc, and a new leg can be regenerated after one molt. Co, coxa; Tr, trochanter; Fe, femur; Ti, tibia; Ta, tarsus