Expression of rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or42a.PG ablates olfactory receptor neuron pb1A: the pb1 sensillum displays an odorant response profile that matches that of the pb1B neuron.

Expression of rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or71a.PG ablates olfactory receptor neuron pb1B: the pb1 sensillum displays an odorant response profile that matches that of the pb1A neuron.

Expression of rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or85e.PG ablates olfactory receptor neuron pb2A: the pb2 sensillum displays an odorant response profile that matches that of the pb2B neuron.

Expression of rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or33c.PG ablates olfactory receptor neuron pb2A: the pb2 sensillum displays an odorant response profile that matches that of the pb2B neuron.

Expression of rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or46a.PG ablates olfactory receptor neuron pb2B: the pb2 sensillum displays an odorant response profile that matches that of the pb2A neuron.

Electrophysiological recordings from coeloconic sensilla of Scer\GAL4^Or35a;rpr^Scer\UAS.cYa mutants reveals a population of sensilla that contain apparently normal ac3A cells but no other cells.

Flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or22a.8197 show abnormal antennal electrophysiology; recordings from the ab3 sensilla lack the large spikes characteristic of the ab3A neuron, while the small spikes characteristic of the ab3B neuron are present. There is no response of the ab3A neuron to a large panel of odours in these animals, although the ab3B neuron responds strongly to all odours that elicit a response in control flies. For some odours, most notably pentyl acetate, the mean response of the ab3B neuron in flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or22a.8197 is greater than that of controls. The olfactory receptor neurons of other large basiconic sensilla appear normal in limited testing. There is no response of the ab3A neuron to a large panel of odours in animals expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or22b.10287, although the ab3B neuron responds strongly to all odours that elicit a response in control flies. For some odours, most notably pentyl acetate, the mean response of the ab3B neuron in flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Or22b.10287 is greater than that of controls.

Flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP show normal locomotion, phototaxis, negative geotaxis and courtship behaviour.

The antennae of flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP have normal external and internal appearance at the light microscope level. However, many defects are seen in the antenna at the ultrastructural level. 80% of basiconic sensilla on the antenna have no neuronal dendrites within their sensory pegs, although the neuronal cell bodies and axons remain intact. In some cases, electron-dense material fills the sensillar lumen, in other cases, ill-defined cellular structures are visible, but often, the entire sensillar lumen appears empty. Approximately two-thirds of the basiconic sensilla have a somewhat thicker cuticle than normal and aberrant pores that do not appear to extend to the internal cavity. The trichoid and coeloconic sensilla appear normal. On the maxillary palps, approximately two-thirds of basiconic sensilla have defects similar to those on the antenna, while one-third appear unaffected.

The antennal lobes of flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP have no apparent defect.

Only 28% of the large basiconic sensilla of the antenna have functional neurons (as judged by the presence of spontaneous action potentials) in flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP compared to 97% of wild-type large basiconic sensilla.

Flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP respond to ethyl acetate, propionic acid and butyric acid with a greatly reduced intensity compared to controls.

Single coeloconic sensilla in the antennae of flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP show a normal response to ethyl acetate, propionic acid and butyric acid.

The electroantennogram responses of flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP to benzaldehyde, 2-heptanone, 2-butanone, ethyl acetate, butyl acetate and ethyl butyrate are significantly reduced compared to wild type, while their responses to octanol and propionic acid do not differ significantly from wild type.

Attraction of flies expressing rpr^Scer\UAS.cYa under the control of Scer\GAL4^Pbprp5.PP to optimal concentrations of ethyl acetate, acetic acid and acetone are greatly reduced compared to wild type in a behavioural trap assay, while responses to optimal concentrations of butyric acid, propionic acid and 2-butanone are not significantly affected. The dose response curve to ethyl acetate is shifted towards higher concentrations.