The retina ofManduca sexta: rhodopsin expression, the mosaic of green-, blue- and UV-sensitive photoreceptors, and regional specialization

Abstract

in the compound eye of Manduca sexta were verified by immunocytochemistry, and the retinal mosaic was mapped, using polyclonal antisera raised against aminoterminal sequences of three identified rhodopsins: P520, P450 and P357. Retinulae are composed of a small proximal cell and seven or eight elongate cells extending across the retina. In each retinula, one or two elongate dv cells oriented in the dorsal-ventral axis of the retinal lattice express either P450 or P357. Six elongate ap and ob cells in the anterior-posterior and oblique axes express P520. The small proximal pr cell also appears to express P520. The retinal mosaic is regionalized into three distinct domains: ventral and dorsal domains that divide the main retina, and a large dorsal rim area. The immunocytochemical data provide a high-resolution map of the Manduca retina that confirms and refines earlier low-resolution ERG spectral sensitivity measurements. The dorsal and ventral domains, separated at a well-defined equatorial border, are distinguished by differences in the proportion of bluesensitive dv cells: these cells dominate the ventral retina but are less abundant in the dorsal retina. Green-sensitive ap and ob receptors are uniformly distributed across the dorsal and ventral domains, and UV-sensitive dv cells are fairly uniformly distributed because many retinulae in the dorsal domain contain only one dv cell. Similarly, dorsal rim retinulae contain only the ventral member of the dv pair of receptors, two-thirds of which express P357. Otherwise, dorsal rim receptors express none of the three sequenced Manduca opsins; they must express rhodopsins that have yet to be cloned.

Visual cues of oviposition sites and spectral sensitivity of Cydia strobilella L.

“…Yet, we have to consider the possibility that we did not pick up the responses of a rare or small photoreceptor type, especially if it was located far from our electrode. Lepidopterans typically possess stacked receptors with one cell contributing only to the proximal part of the retina (Briscoe, 2008;White et al, 2003, Belušič et al, 2017. In the African armyworm moth, Spodoptera exempta, the basal cell is maximally sensitive to wavelengths of 560 nm (Langer et al, 1979;Meinecke & Langer, 1981).…”

“…Preliminary analyses of chromatic contrast for all possible combinations of abundances between 1:1:1 to 1:4:10 (for the UV:blue:green receptors; upper limit derived from data on the tobacco hornworm, Manduca sexta, cf. White et al, 2003) and absolute noise between 0.08 and 0.12 (cf. Vorobyev et al, 2001) indicated, without exceptions, lowest contrast for 1:1:10, 0.12 (receptor contrast, absolute noise), and highest contrast for 1:4:1, 0.08.…”

Beauty in the eye of the beholder: the two blue opsins of lycaenid butterflies and the opsin gene-driven evolution of sexually dimorphic eyes

“…The presence of a fourth visual pigment mRNA BRh2, together with UVRh and BRh1, furnishes Lycaena with six ommatidial subtypes in the ventral eye area (Fig.·4), twice the number found in any other lepidopteran (Arikawa, 2003;Briscoe et al, 2003;White et al, 2003;Sauman et al, 2005;Zaccardi et al, 2006). Even in Pieris rapae (Arikawa et al, 2005), which as noted above has independently evolved a violet receptor from a duplicate blue opsin gene, only three ommatidial types have been reported: those expressing UV-UV, UV-B, and V-V opsin mRNAs.…”

“…Unlike the unusual BRh1 mRNA expression in the outer R3-8 photoreceptor cells of the L. rubidus dorsal eye, the typical lepidopteran expresses short wavelength opsin mRNAs only in the R1 and R2 cells (Kitamoto et al, 2000;Briscoe et al, 2003;White et al, 2003;Sauman et al, 2005). Closer inspection of UVRh, BRh1 and BRh2 expression in individual ommatidia indicated that these transcripts are also present in the R1 and R2 photoreceptor cells of both sexes (Fig.·4).…”

“…Most lepidopteran eyes contain a minimum of three visual pigments with absorbances that peak at ~350·nm (UV), 440·nm (blue, B) and 530·nm (long wavelength, LW) (reviewed in Briscoe and Chittka, 2001). In the sphingid moth, the painted lady and monarch butterfly, these visual pigments are encoded by paralogous UV, B and LW opsin genes, which were present in the ancestor of all lepidopterans (Briscoe et al, 2003;White et al, 2003;Sauman et al, 2005). Deviations from this basic plan have been described in the most primitive of butterfly families, the papilionids, in which two rounds of duplication of the LW eye opsin gene have occurred (Briscoe, 1998;Kitamoto et al, 1998;Briscoe, 2001); and in the pierids, in which a duplicate blue opsin gene has been reported (Arikawa et al, 2005).…”