Axonal projections from transplanted ectopic legs in an insect.
Ectopic legs were produced in the fleshfly Sarcophaga bullata by transplantation of leg imaginal discs. Cobalt or horseradish peroxidase (HRP) fills from these supernumerary legs showed that their sensory axons invariably innervate the metathoracic leg neuropil via an abdominal nerve. This was so irrespective of whether they differentiated from pro-, meso-, or metathoracic leg disc. Implantation of left leg discs on the right side and vice versa revealed that the site of implantation determined which side (left or right) of the ganglion was innervated. In general, the same results were obtained when the implantation was made after removal of a leg disc from the host, except in a few instances in which the implanted leg directly innervated the deafferented leg neuropil. The results indicate that axonal pathfinding from the imaginal discs in this insect is via contact guidance along preexisting nerves or imaginal disc stalks.
D000818:Animals; D004175:Diptera / Q000502:physiology*; D005121:Extremities / Q000294:innervation* / Q000637:transplantation; D009424:Nervous System Physiological Phenomena