Deletion that completely removes both Obp83a and Obp83b transcription units. Sequence cassette encoding 1. a single attP site and 2. a Disc\RFP^{DsRed(T1).3xP3.cHa} marker flanked by loxP sites has been inserted in place of the deleted sequence.

Df(3R)OS-EF- mutants are viable and fertile.

In Df(3R)OS-EF- mutants, trichoid sensilla neuron Or47b in shows increased spontaneous activity, and a significant decrease in activity in response to the odorant trans-2-hexenal, but not to the odorants methyl laurate, as compared to controls; Or88a neurons do not show changes in activity in response to the odorants methyl myristate, methyl palmitate and 2-octanone, as compared to controls; intermediate sensilla neuron Or83c shows a significant increase in activity in response to the odorant farnesol, but unchanged spontaneous activity, as compared to controls. Trichoid/intermediate sensilla neurons Or13a, Or23a, Or19a, Or2a/Or43a, Or67d neurons do not show significant differences in spontaneous activity or odorant-induced response, as compared to controls. Basiconic sensilla neurons do not show significant differences in odorant-induced response or spontaneous activity, as compared to controls.

In Df(3R)OS-EF- mutants, ai2 sensilla/Or83c neurons, at1 sensilla/Or67d and at4/Or47b neurons show delayed deactivation upon stimulation with farnesol, cVA and trans-2-hexenal, respectively, despite of similar sensitivity and activation kinetics to controls; Or88a neurons also show delayed deactivation upon stimulation; ai2 sensilla/Or83c neurons show delayed deactivation upon stimulation with farnesal and farnesene, but normal response to 3-hexanol and geraniol.