Remodelling of neuromuscular systems during insect metamorphosis

Abstract

During metamorphosis in the hawkmoth, Manduca sexta, the larval thoracic legs are replaced by a new set of adult legs that include new sensory neurons and muscles, and participate in new patterns of locomotor activity. Larval leg motoneurons persist to innervate the new adult leg muscles, but undergo striking changes in dendritic morphology that are regulated by the insect steroid, 20-hydroxyecdysone. In the periphery, the motor terminals regress as larval muscles degenerate, and expand as new adult muscles form from myoblasts. Evidence obtained both in vivo and in vitro suggests that the proliferation of myoblasts during metamorphosis is dependent upon innervation. © 1995 by the American Society of Zoologists.