Courtship song of Nlg2^KO17 males contain regular pulse and sine songs (as occurs in wild type), but the average interpulse interval is significantly shorter (45ms) than normal (47.6ms) and sine song intensity is reduced. Mutant males keep the wing in an extended position for a significantly prolonged period of time compared to wild-type males when a female moves away during courtship.

Social interactions are altered in Nlg2^KO17 flies. When five male and five female flies of the same genotype are placed in a featureless round arena, the median distance of individual flies to all other flies is significantly increased in Nlg2^KO17 mutants at 1 minute. The mutant flies do not show a regular increase in median inter-individual distance over time, in contrast to wild type.

Mutant flies show altered locomotor patterns compared to wild type. They do not separate translational and rotational activity, resulting in them walking in a curve (in contrast, wild-type flies change walking direction by stopping, turning to a new direction and then continuing walking).

In a competitive courtship assay with two males of the same genotype, Nlg2^KO17 males spend a similar total time courting the female and initiate courtship at similar frequencies as wild-type males. However, the courtship bouts of mutant males are prolonged compared to those of wild-type males.

In a mixed competitive courtship assay (one Nlg2^KO17 male, one wild-type male), the mutant males perform less courtship, initiate courtship more rarely and continue individual courtship bouts for shorter periods than the wild-type males. In 60% of the mixed assays the mutant male performs no courtship at all.

Total duration of agonistic interactions are reduced in mutant males compared to wild type in both competitive courtship assays with two males of the same genotype and in a mixed competitive courtship assay.

Isolated mutant males show no significant difference in total locomotor activity compared to controls, but they show a less pronounced difference between high activity and low activity periods than wild-type males when raised in 12 hour light: 12 hour dark cycles.

Electroretinograms of mutant males are not significantly different from wild type and acoustic stimulation reveals no significant difference in auditory thresholds compared to wild type.

neuroligin^KO17 mutants exhibit no detectable abnormalities in body size or morphology.

Neither the amplitude nor frequency of spontaneously occuring mEJPs are significantly different to wild-type in neuroligin^KO17 mutants. In contrast, the amplitude of stimulus-evoked EJPs shows a small but significant increase in neuroligin^KO17 and neuroligin^KO17/Df(2L)ED7007 mutants. These effects are seen at both high (0.8mM) and low (0.2mM) calcium levels.