title: Broadband Photoreceptors Are Involved in Violet Light Preference in the Parasitoid Fly Exorista Japonica.
abstract: Phototaxis has been described in many insects, which are often attracted to specific wavelengths of light. However, little is known about phototaxis in parasitoid insect species that are potentially useful for integrated pest management. In this study, we investigated the wavelength dependency of the phototactic behavior of the parasitoid fly Exorista japonica and its possible mechanism. Multiple-choice tests with six monochromatic stimuli revealed that the flies were specifically attracted to violet light peaking at 405 nm, which was unexpected because insects are generally attracted to ultraviolet or green light. We measured the spectral sensitivity of the compound eye, and found that the sensitivity peaked at 340 nm, as in other brachyceran flies. We used statistical modeling and optimization of the process parameters to predict the type of photoreceptor contributing to the violet preference. The analysis revealed that the wavelength preference could be explained by linear models of the quanta received by photoreceptors, including the R1-6 broadband receptors. The broadband receptors appear to contribute positively, whereas the R7-8 narrowband receptors contribute negatively to achieve the violet preference; i.e., spectral opponency might be involved.
authors.affiliation: Institute of Agrobilogical Science, NARO, Tsukuba, Ibaraki, Japan.|Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tokushima
authors.affiliation: Institute of Agrobilogical Science, NARO, Tsukuba, Ibaraki, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Uehara
authors.affiliation: Institute of Agrobilogical Science, NARO, Tsukuba, Ibaraki, Japan.
authors.forename: Terumi
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Laboratory of Neuroethology, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Arikawa
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Yooichi
authors.initials: Y
authors.lastname: Kainoh
authors.affiliation: Institute of Agrobilogical Science, NARO, Tsukuba, Ibaraki, Japan.
authors.forename: Masami
authors.identifier: http://orcid.org/0000-0002-8447-9295
authors.initials: M
authors.lastname: Shimoda
mesh_terms: D000818:Animals; D003116:Color; D004175:Diptera / Q000502:physiology*; D004596:Electroretinography; D005260:Female; D008027:Light; D008297:Male; D008954:Models, Biological; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D000071444:Phototaxis / Q000502:physiology; D014466:Ultraviolet Rays