title: The role of UV in crab spider signals: effects on perception by prey and predators.
abstract: Australian crab spiders Thomisus spectabilis sit on the petals of flowers and ambush prey such as honeybees. White-coloured T. spectabilis reflect in the UV (UV+ spiders) and previous research has shown that their presence, curiously, attracts honeybees to daisies. We applied an UV-absorber (Parsol) to create UV-absorbing (UV-) spiders that did not reflect any light below 395 nm wavelength. These physical changes of visual signals generated by crab spiders caused honeybees to avoid flowers with UV- spiders on their petals. They also affected the perception of UV- spiders by honeybees and a potential avian predator (blue tits). Compared to UV+ spiders, UV- spiders produced less excitation of the UV-photoreceptors in honeybees and blue tits, which translated into a reduced UV-receptor contrast and a reduced overall colour contrast between UV- spiders and daisy petals. Our results reveal that a clean physical elimination of reflection in the UV range affects perception in predators and prey and ultimately changes the behaviour of prey.
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, 2109 NSW Australia. astrid.heiling@univie.ac.at
authors.forename: Astrid M
authors.initials: AM
authors.lastname: Heiling
authors.forename: Ken
authors.initials: K
authors.lastname: Cheng
authors.forename: Lars
authors.initials: L
authors.lastname: Chittka
authors.forename: Ann
authors.initials: A
authors.lastname: Goeth
authors.forename: Marie E
authors.initials: ME
authors.lastname: Herberstein
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology / Q000528:radiation effects; D003118:Color Perception / Q000502:physiology / Q000528:radiation effects; D035264:Flowers; D046109:Passeriformes / Q000502:physiology; D010858:Pigmentation / Q000502:physiology; D011235:Predatory Behavior / Q000502:physiology* / Q000528:radiation effects*; D013112:Spiders / Q000502:physiology*; D014466:Ultraviolet Rays