Meeting Abstract
Since Darwin, diversity in species recognition and mate attraction systems has generated wide interest. However, understanding how such high phenotypic diversity is generated at the molecular level is challenging. To address how differences in mating signals between species are produced, we are studying cypridinid ostracods, which use species-specific bioluminescent displays to attract mates. In ostracods, bioluminescence is produced externally when an enzyme, luciferase, oxidizes the substrate vargulin to produce blue light. These complex patterns vary in many ways, like the duration of each discrete pulse in a train of pulses. But, given their simple genetic basis, they are tractable for connecting genotype to phenotype. Here, we assess the extent to which differences in bioluminescence reflect variation in enzyme sequence. We stimulated light production via mild electric shock from individuals of over 25 species and recorded the pulse decay. We compared these decay rates to luciferase sequences generated from de novo transcriptomes in a subset of species, predicting that certain sequence changes are correlated with shifts in decay. First, we found significant variation in both decay rates and enzymes between species. We also found that a small number of sequence changes are associated with divergent phenotypes. Future work will address both the molecular basis of enzyme differences, and if phenotypic differences elicit alternative mating decisions in display receivers. Together, these data help us assess how specific genetic changes contribute to differences in complex signaling behaviors between species.
