title: Intensity contrast as a crucial cue for butterfly landing.
abstract: Papilio butterflies use a tetrachromatic color vision to discriminate a rewarding flower, approach, land and take nectar from the flower. In the course of further analyzing their foraging behavior in a laboratory condition, we found that some butterflies could not land on the target flower even they discriminated and tried to land on it, especially when the target was dark. This phenomenon, which we call "landing suppression", indicates that the cue for landing differs from the cue for visually locating a flower. We hypothesized that a possible cue for landing was intensity contrast between the target and background, and have initiated to test this hypothesis. We tested the butterflies' landing behavior to targets of various colors and intensities presented on background of black or various densities of gray. As a result, the landing was most strongly suppressed when the intensity contrast was close to zero irrespective of the target colors, suggesting that the butterflies used the target-background intensity contrast when landing.
authors.affiliation: Graduate School of Integrated Sciences, Yokohama City University, Yokohama, Japan.
authors.forename: Hisaharu
authors.initials: H
authors.lastname: Koshitaka
authors.forename: Kentaro
authors.initials: K
authors.lastname: Arikawa
authors.forename: Michiyo
authors.initials: M
authors.lastname: Kinoshita
mesh_terms: D000818:Animals; D002080:Butterflies / Q000502:physiology*; D003116:Color; D055253:Color Vision / Q000502:physiology*; D054910:Compound Eye, Arthropod / Q000502:physiology / Q000528:radiation effects; D015350:Contrast Sensitivity / Q000502:physiology*; D003463:Cues; D005106:Exploratory Behavior / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D035264:Flowers / Q000502:physiology; D008029:Lighting; D010775:Photic Stimulation / Q000379:methods; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology / Q000528:radiation effects; D011597:Psychomotor Performance / Q000502:physiology*