Scientists have shown for the first time that there is a strong correlation between the complex patterns on male darters and their highly-variable environments. The findings support and expand upon sensory drive theory, which states that the environment influences which sexual signals, like visual patterns, are selected for. Previous sensory drive research looked at simple signals (e.g. colors), but Hulse used Fourier analysis to greatly expand that work.

Source: How the darter got stripes: Expanding a sexual selection theory explains animal patterns