Nucleotide and amino acid sequences of luciferase peptides that are encoded by genes within the genome of Arachnocampa (Diptera) are disclosed. Specifically provided are functional ATP-dependent luciferases that catalyze luminescence reactions with emission spectra within the blue portion of the spectrum. The present invention specifically provides isolated peptide and nucleic acid molecules, methods of identifying orthologs and active subsequences of the enzyme peptides, and methods of identifying modulators and substrates of the luciferase peptides. Methods of assays, including multiple reporter assays utilizing at least two ATP-dependent luciferases are provided.