All flies were maintained on standard cornmeal and molasses agar food at 25°C and 70% humidity. The BxJ mutant has been described previously [24]. The dLmo loss-of-function mutants EP1306, Hdp[R26] and Pdrm[5–73] have been described previously [18]. Lines were out-crossed for at least five generations to a w1118 stock isogenic for Chromosomes II and III; these “w; iso” flies served as the genetic background control for quantitative PCR and microarray experiments. The dAlk P-element insertion mutant MB06458 was obtained from the Bloomington Drosophila Stock Center (Bloomington, IN, USA) and f01491 was obtained from the Exelixis Collection at the Harvard Medical School. The presence of each insertion in the Alk locus was confirmed by PCR. Lines were outcrossed for at least 5 generations to white Berlin (f01491) or 2202U (MB06458). The white Berlin and 2202U strains served as genetic background controls for the corresponding mutant lines in behavioral assays. All experiments used adult male flies which were collected 2–4 days following eclosion.
