Cha^l13 mutants exhibit changes in dendritic arbors in a fraction of MN-DA3 and MN-L1 cells, as compared to wild-type, exhibiting smaller than normal dendritic aborisations in the intermediate neuropile. However, all other motorneurons studied in 18.5 hour Cha^l13 mutant embryos and innervated territories are comparable to wild-type, indicating that excitatory synaptic input is not essential for the development of normal overall motorneuron dendrite morphology or the formation of the myotopic map.