Antipredatory Function of Head Shape for Vipers and Their Mimics
|dc.identifier.citation||Valkonen JK, Nokelainen O, Mappes J (2011) Antipredatory Function of Head Shape for Vipers and Their Mimics. PLoS ONE 6(7): e22272. doi:10.1371/journal.pone.0022272|
|dc.description.abstract||Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation) when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated. We experimentally tested if the triangular head shape typical of vipers offers protection against predation. We compared the predation pressure of free-ranging predators on artificial snakes with triangular-shaped heads against the pressure on replicas with narrow heads. Snakes of both head types had either zigzag patterned bodies, typical of European vipers, or plain (patternless) bodies. Plain snakes with narrower Colubrid-like heads suffered significantly higher predation by raptors than snakes with triangular-shaped heads. Head shape did not, however, have an additive effect on survival in zigzag-patterned snakes, suggesting that species which differ from vipers in colouration and pattern would benefit most from behavioural mimicry. Our results demonstrate that the triangular head shape typical of vipers can act as a warning signal to predators. We suggest that head-shape mimicry may be a more common phenomenon among more diverse taxa than is currently recognised.||fi|
|dc.publisher||Public Library of Science|
|dc.title||Antipredatory Function of Head Shape for Vipers and Their Mimics|
|dc.contributor.laitos||Bio- ja ympäristötieteiden laitos||fi|
|dc.contributor.laitos||The Department of Biological and Environmental Science||en|
|dc.rights.copyright||© 2011 Valkonen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
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Except where otherwise noted, this item's license is described as © 2011 Valkonen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.