title: The unusual eyes of Xenos peckii (Strepsiptera: Xenidae) have green- and UV--sensitive photoreceptors.
abstract: The highly specialized evolution of Strepsiptera has produced one of the most unusual eyes among mature insects, perhaps in line with their extremely complex and challenging life cycle. This relatively rare insect order is one of the few for which it has been unclear what spectral classes of photoreceptors any of its members may possess, an even more apt question given the nocturnal evolution of the group. To address this question, we performed electroretinograms on adult male Xenos peckii: we measured spectral responses to equi-quantal monochromatic light flashes of different wavelengths, and established VlogI relationships to calculate spectral sensitivities. Based on opsin template fits, we found maximal spectral sensitivity (λmax) in the green domain at 539 nm. Application of a green light to 'bleach' green receptors revealed that a UV peak was contributed to by an independent UV opsin with a λmaxof 346 nm. Transcriptomics and a phylogenetic analysis including 50 other opsin sequences further confirmed the presence of these two opsin classes. While these findings do not necessarily indicate that these unorthodox insects have color vision, they raise the possibility that UV vision plays an important role in the ability of X. peckii males to find the very cryptic strepsipteran females that are situated within their wasp hosts.
authors.affiliation: Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Marisano
authors.initials: M
authors.lastname: James
authors.affiliation: Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA.
authors.forename: Sri Pratima
authors.initials: SP
authors.lastname: Nandamuri
authors.affiliation: Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Stahl
authors.affiliation: Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA elke.buschbeck@uc.edu.
authors.forename: Elke K
authors.identifier: 0000-0001-8563-0826
authors.initials: EK
authors.lastname: Buschbeck
mesh_terms: D000818:Animals; D004596:Electroretinography; D005260:Female; D008297:Male; D055355:Opsins / Q000235:genetics / Q000378:metabolism; D010271:Parasites / Q000235:genetics / Q000648:ultrastructure; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology* / Q000648:ultrastructure; D010802:Phylogeny; D013057:Spectrum Analysis; D059467:Transcriptome / Q000235:genetics; D014466:Ultraviolet Rays; D014863:Wasps / Q000166:cytology* / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D055355:Opsins
keywords: Color vision; Invertebrate vision; Spectral sensitivity