TY - JOUR
T1 - Losing the trait without losing the signal
T2 - Evolutionary shifts in communicative colour signalling
AU - Romero-Diaz, Cristina
AU - Rivera, Julio A.
AU - Ossip-Drahos, Alison G.
AU - Zúñiga-Vega, José Jaime
AU - Vital-García, Cuauhcihuatl
AU - Hews, Diana K.
AU - Martins, Emilia
N1 - Funding Information:
We thank Stephanie Campos, Jesualdo Fuentes-G., Heather Rich, Piyumika Suriyampola and three anonymous reviewers for helpful comments on the manuscript. We are grateful to Jake Pruett, Patrick Cain and Stephanie Campos for help in the field. We thank Joe Macedonia for providing us with spectral sensitivities for Crotaphytus cone classes. We also are grateful to the staff and volunteers at the Southwestern Research Station (of the American Museum of Natural History) and the Parque Nacional Huatulco (Oaxaca, Mexico) for logistical support in the field. We appreciate permission from Carolyn Ohls to work at Christmas Mountain Oasis, TX. We thank the Indiana State Department of Natural Resources, the United States Forest Service, the Arizona Department of Game and Wildlife, the California Department of Fish and Wildlife, the Texas Parks and Wildlife Department, Secretaría de Medio Ambiente y Recursos Naturales Oficio Núm. SGPA/DGVS/04386/12, the Indiana University Bloomington Institutional Animal Care and Use Committee (Animal Use and Care Protocol 10-013, approved on 8 June 2010 to EPM), and the Indiana State University IACUC (Protocol 492636 to DKH), for permission to conduct this work. This material is based upon work supported by the National Science Foundation under grant numbers IOS-1050274 to EPM and IOS-1052247 to DKH.
Funding Information:
National Science Foundation, Grant/Award Number: IOS-1050274 and IOS-1052247
Publisher Copyright:
© 2019 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2019 European Society For Evolutionary Biology
PY - 2019/4
Y1 - 2019/4
N2 - Colour signalling traits are often lost over evolutionary time, perhaps because they increase vulnerability to visual predators or lose relevance in terms of sexual selection. Here, we used spectrometric and phylogenetic comparative analyses to ask whether four independent losses of a sexually selected blue patch are spectrally similar, and whether these losses equate to a decrease in conspicuousness or to loss of a signal. We found that patches were lost in two distinct ways: either increasing reflectance primarily at very long or at very short wavelengths, and that species with additional colour elements (UV, green and pink) may be evolutionary intermediates. In addition, we found that patch spectral profiles of all species were closely aligned with visual receptors in the receiver's retina. We found that loss of the blue patch makes males less conspicuous in terms of chromatic conspicuousness, but more conspicuous in terms of achromatic contrast, and that sexual dimorphism often persists regardless of patch loss. Dorsal surfaces were considerably more cryptic than were ventral surfaces, and species in which male bellies were the most similar in conspicuousness to their dorsal surfaces were also the most sexually dimorphic. These results emphasize the consistent importance of sexual selection and its flexible impact on different signal components through evolutionary time.
AB - Colour signalling traits are often lost over evolutionary time, perhaps because they increase vulnerability to visual predators or lose relevance in terms of sexual selection. Here, we used spectrometric and phylogenetic comparative analyses to ask whether four independent losses of a sexually selected blue patch are spectrally similar, and whether these losses equate to a decrease in conspicuousness or to loss of a signal. We found that patches were lost in two distinct ways: either increasing reflectance primarily at very long or at very short wavelengths, and that species with additional colour elements (UV, green and pink) may be evolutionary intermediates. In addition, we found that patch spectral profiles of all species were closely aligned with visual receptors in the receiver's retina. We found that loss of the blue patch makes males less conspicuous in terms of chromatic conspicuousness, but more conspicuous in terms of achromatic contrast, and that sexual dimorphism often persists regardless of patch loss. Dorsal surfaces were considerably more cryptic than were ventral surfaces, and species in which male bellies were the most similar in conspicuousness to their dorsal surfaces were also the most sexually dimorphic. These results emphasize the consistent importance of sexual selection and its flexible impact on different signal components through evolutionary time.
KW - Sceloporus lizard
KW - colouration
KW - phylogenetic comparative methods
KW - sexual selection
KW - signal evolution
KW - visual communication
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U2 - 10.1111/jeb.13416
DO - 10.1111/jeb.13416
M3 - Article
C2 - 30685886
AN - SCOPUS:85061271223
SN - 1010-061X
VL - 32
SP - 320
EP - 330
JO - Journal of Evolutionary Biology
JF - Journal of Evolutionary Biology
IS - 4
ER -