Molecular Evidence of Long Wavelength Spectral Sensitivity in the Reverse Sexually Dichromatic Convict Cichlid (Amatitlania nigrofasciata)

The Convict Cichlid, Amatitlania nigrofasciata, is a popular model organism for behavioral ecologists to study mate choice, monogamy, and parental care. This freshwater Central American fish displays the rare phenotype of reverse sexual dichromatism, and despite the species’ pervasiveness in behavioral laboratories, the role of female ornamentation in this system is uncertain. To better understand the function of female ornamentation, this study characterizes the visual sensitivity of A. nigrofasciata with particular attention to the long wavelength spectral sensitivity needed to perceive female coloration. We find Convict Cichlids to express a trichromatic complement of opsin proteins: SWS2A, SWS2B, and LWS. After confirming the expression of a LWS opsin gene, we inspected the LWS gene in order to speculate on directional selection potentially resulting in heightened sensitivity to female ornamentation. We examined seven tuning residues in the coding sequence of the LWS opsin gene of A. nigrofasciata and present sequence data that suggest Convict Cichlids have heightened long wavelength sensitivity that is tuned to the female ornament present.