Third instar larvae expressing fend^Scer\UAS.cUa under the control of Scer\GAL4^how-24B show defects show defects in the targeting of muscle 12 by motor neurons. The terminal branch of ISNb projects to and form synaptic endings on muscle 12 normally. However, in 44.4% of hemisegments, the nerve ending fail to stabilise on muscle 12 and instead send back collaterals that turn back on to muscle 13 and form a number of ectopic synapses on the muscle.

Third instar larvae expressing fend^Scer\UAS.cUa under the control of Scer\GAL4^l(3)H94-H94 have ectopic nerve endings on muscle 13 in 48% of segments.

Expression of fend^Scer\UAS.cUa under the control of Scer\GAL4^5053A rarely induces the formation of ectopic nerve endings on muscle 13 in third instar larvae.