First instar larvae expressing Ork1Scer\UAS.cUa under the control of Scer\GAL4Lim3b have a significantly higher proportion of olfactory sensory neurons (OSNs) with immature-like morphologies (with broad axonal terminals and multiple filopodia that are more characteristic of earlier developmental stages) than control larvae. The OSNs occupy a larger percentage of the antennal lobe synaptic volume than controls.