Nrg⁸⁴⁹/Nrg⁸⁹² females show normal sexual receptivity when mated to wild-type males.

Homozygous females show a moderate reduction in sexual receptivity (56% mate) compared to wild-type controls when mated to wild-type males.

Nrg^l4/Nrg⁸⁹², Nrg^G0099/Nrg⁸⁹², Nrg^G0413/Nrg⁸⁹² and Nrg^G0488b/Nrg⁸⁹² females show reduced sexual receptivity compared to wild-type controls when mated to wild-type males.

Nrg^l10/Nrg⁸⁹² females show normal sexual receptivity at 18 and 25[o]C, but show reduced receptivity at 29[o]C when mated to wild-type males.

Homozygous males show defects in courtship behaviour relative to wild-type controls when mated to wild-type females. The mean latency is not significantly different from wild type, but they show significantly extended mating speeds. Once they are courting a female, the mutant males tend to have more breaks in their courtship than normal.

Flies have a number of brain defects, the exact phenotype depending on the genetic background. In the original genetic background in which it was induced, Nrg⁸⁹² has a similar phenotype to that of Nrg⁸⁴⁹, but the mushroom body defects are less severe. The peduncle and lobes are present but poorly developed. All flies have ellipsoid body defects, and most flies have fan-shaped body defects. Females are sterile. When placed in a Canton S background, the Nrg⁸⁹² phenotype is altered, with the mushroom body and central complex phenotypes becoming more severe.

Abnormalities in central body and mushroom body. About 400 Kenyon cell fibers miss the fiber bundle of pedicle, forming an extra lobe on lateral side of calyx. Ellipsoid body abnormal, being divided into 2 parts along the midline, or opening ventrally.