SISON-MANGUS, Marilou P.; BRISCOE, Adriana D.; University of California, Irvine: Sexually dimorphic distribution of opsins in the Lycaena rubidus retina

The distribution of visual pigments in Lycaena rubidus is reported to be sexually dimorphic on the basis of microspectrophotometric measurements (Bernard and Remington 1991). The dorsal region of the male L. rubidus is described to be dichromatic while the ventral region is trichromatic. The female L. rubidus, on the other hand, has both dorsal and ventral regions of the eye that are trichromatic. Recently, we molecularly characterized from head-derived L. rubidus cDNA four opsins including the duplicated genes, BRh1 and BRh2 (Briscoe and Sison-Mangus 2004). This presented an opportunity to study the visual pigment mRNA distribution in the L. rubidus retina. Using in situ hybridization, all four opsins (LWRh, UVRh, BRh1 and BRh2) were found to be expressed in the retina of both male and female L. rubidus. Single-staining of riboprobes in adjacent sections revealed that in the dorsal region of the eye in male L. rubidus, only BRh1 and UVRh opsins are present while in female L. rubidus, all four opsins are present. The ventral region of the eye in both sexes, on the other hand, appears to express all four opsins. This data, thus, strongly supports the previous report that L. rubidus have receptor mosaics that are sexually dimorphic.