Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators

Joseph M. MacEdonia, A. Kristopher Lappin, Ellis R. Loew, Jimmy A. McGuire, Paul S. Hamilton, Melissa Plasman, Yoni Brandt, Julio A. Lemos-Espinal, Darrell J. Kemp

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Selection should favour coloration in organisms that is more conspicuous to their own visual system than to those of their predators or prey. We tested this prediction in Dickerson's collared lizard (Crotaphytus dickersonae), a sexually dichromatic desert reptile that preys on insects and smaller lizard species, and which in turn is prey for birds and snakes. We modelled the spectral sensitivities of the lizards and their avian and snake predators, and compared the conspicuousness of the lizards' entire colour patterns with each class of viewers. Almost all comparisons involving females strongly supported our prediction for greater chromatic and brightness conspicuousness against local terrestrial visual backgrounds to their own modelled visual system than to those of avian and snake predators. Males, in contrast, exhibited far fewer cases of greater conspicuousness to their own visual system than to those of their predators. Our own perception of spectral similarity between blue C. dickersonae males and a local nonterrestrial visual background (i.e. the Sea of Cortéz) prompted a further investigation. We compared sea (and sky) radiance with dorsum radiance of C. dickersonae males and with males from two distantly-related Crotaphytus collaris populations in which males possess blue bodies. In all three visual models, C. dickersonae males exhibited significantly lower chromatic contrast with the sea (and sky) than did their noncoastal, blue-bodied congeners. Among potential explanations, the blue body coloration that is unique to male C. dickersonae may offset, if only slightly, the cost of visibility to predators (and to prey) through reduced contrast against the extensive, local, nonterrestrial blue backgrounds of the sea and sky.

LanguageEnglish
Pages749-765
Number of pages17
JournalBiological Journal of the Linnean Society
Volume97
Issue number4
DOIs
Publication statusPublished - Aug 2009
Externally publishedYes

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lizard
lizards
eyes
predator
predators
snake
color
snakes
radiance
prediction
Gulf of California
birds of prey
reptile
visibility
reptiles
deserts
desert
insect
bird
insects

Keywords

  • Coloration
  • Predation pressure
  • Sensory drive
  • Spectral sensitivity
  • Visual ecology

Cite this

MacEdonia, Joseph M. ; Lappin, A. Kristopher ; Loew, Ellis R. ; McGuire, Jimmy A. ; Hamilton, Paul S. ; Plasman, Melissa ; Brandt, Yoni ; Lemos-Espinal, Julio A. ; Kemp, Darrell J. / Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators. In: Biological Journal of the Linnean Society. 2009 ; Vol. 97, No. 4. pp. 749-765.
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title = "Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators",
abstract = "Selection should favour coloration in organisms that is more conspicuous to their own visual system than to those of their predators or prey. We tested this prediction in Dickerson's collared lizard (Crotaphytus dickersonae), a sexually dichromatic desert reptile that preys on insects and smaller lizard species, and which in turn is prey for birds and snakes. We modelled the spectral sensitivities of the lizards and their avian and snake predators, and compared the conspicuousness of the lizards' entire colour patterns with each class of viewers. Almost all comparisons involving females strongly supported our prediction for greater chromatic and brightness conspicuousness against local terrestrial visual backgrounds to their own modelled visual system than to those of avian and snake predators. Males, in contrast, exhibited far fewer cases of greater conspicuousness to their own visual system than to those of their predators. Our own perception of spectral similarity between blue C. dickersonae males and a local nonterrestrial visual background (i.e. the Sea of Cort{\'e}z) prompted a further investigation. We compared sea (and sky) radiance with dorsum radiance of C. dickersonae males and with males from two distantly-related Crotaphytus collaris populations in which males possess blue bodies. In all three visual models, C. dickersonae males exhibited significantly lower chromatic contrast with the sea (and sky) than did their noncoastal, blue-bodied congeners. Among potential explanations, the blue body coloration that is unique to male C. dickersonae may offset, if only slightly, the cost of visibility to predators (and to prey) through reduced contrast against the extensive, local, nonterrestrial blue backgrounds of the sea and sky.",
keywords = "Coloration, Predation pressure, Sensory drive, Spectral sensitivity, Visual ecology",
author = "MacEdonia, {Joseph M.} and Lappin, {A. Kristopher} and Loew, {Ellis R.} and McGuire, {Jimmy A.} and Hamilton, {Paul S.} and Melissa Plasman and Yoni Brandt and Lemos-Espinal, {Julio A.} and Kemp, {Darrell J.}",
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MacEdonia, JM, Lappin, AK, Loew, ER, McGuire, JA, Hamilton, PS, Plasman, M, Brandt, Y, Lemos-Espinal, JA & Kemp, DJ 2009, 'Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators', Biological Journal of the Linnean Society, vol. 97, no. 4, pp. 749-765. https://doi.org/10.1111/j.1095-8312.2009.01217.x

Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators. / MacEdonia, Joseph M.; Lappin, A. Kristopher; Loew, Ellis R.; McGuire, Jimmy A.; Hamilton, Paul S.; Plasman, Melissa; Brandt, Yoni; Lemos-Espinal, Julio A.; Kemp, Darrell J.

In: Biological Journal of the Linnean Society, Vol. 97, No. 4, 08.2009, p. 749-765.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Conspicuousness of Dickerson's collared lizard (Crotaphytus dickersonae) through the eyes of conspecifics and predators

AU - MacEdonia, Joseph M.

AU - Lappin, A. Kristopher

AU - Loew, Ellis R.

AU - McGuire, Jimmy A.

AU - Hamilton, Paul S.

AU - Plasman, Melissa

AU - Brandt, Yoni

AU - Lemos-Espinal, Julio A.

AU - Kemp, Darrell J.

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