Transcriptomes of 10 North American firefly species

Genes underlying signal reception should evolve to maximize signal detection in a particular environment. In animals, opsins, the protein component of visual pigments, are predicted to evolve according to this expectation. Fireflies are known for their bioluminescent mating signals. The eyes of nocturnal species are expected to maximize detection of conspecific signal colors emitted in the typical low-light environment. This is not expected for species that have transitioned to diurnal activity in bright daytime environments. Here we test the hypothesis that opsin gene sequence plays a role in modifying firefly eye spectral sensitivity. We use genome and transcriptome sequencing in four firefly species and transcriptome sequencing in six additional species to identify all opsin genes present in fireflies and to characterize their evolution. We also investigate expression of opsins in different tissues. Fireflies are a rich system in which to investigate the evolution of signals, receptors, and signaling environments. These resources usher these investigations into the genomic era.