Avoiding detection: effects of prey pattern regularity, background matching and complexity of the habitat background
(English)Manuscript (preprint) (Other academic)
In this study we test how aspects of prey colour pattern regularity affect crypsis and how visual complexity of the background affects prey detection. We performed two predation experiments with artificial prey and backgrounds, using blue tits (Cyanistes caeruleus) as predators. In the first experiment we found that a prey pattern consisting of variable element shapes did not compensate for mismatching pattern elements, because a variable pattern with some mismatching element shapes was easier to detect than a variable pattern with background-matching element shapes only. Contrary to a previous hypothesis, a pattern with regular, background-matching element shapes was not easier to detect than the pattern with variable, background-matching shapes. All prey types were easier to detect on a simple than on a complex background with more diverse and complex element shapes. In the second experiment we used prey pattern consisting of invariable, background-matching elements and tested how spatial regularity of the elements affects crypsis. We found that on a complex background the spatially irregular prey with randomly placed pattern elements was more difficult to detect than the regular prey with all elements aligned, but on a simple background both prey types were equally easy to detect. Here background complexity was due to element shape complexity only. In conclusion, our study shows that spatial regularity of prey pattern but not regularity due to invariable pattern element shapes deteriorates crypsis. Visually complex habitat backgrounds and specifically those consisting of elements with complex shapes make detection of cryptic prey difficult.
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:su:diva-30544OAI: oai:DiVA.org:su-30544DiVA: diva2:272845