Losing the trait without losing the signal: Evolutionary shifts in communicative colour signalling

Cristina Romero-Diaz, Julio A. Rivera, Alison G. Ossip-Drahos, José Jaime Zúñiga-Vega, Cuauhcihuatl Vital-García, Diana K. Hews, Emilia Martins

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)320-330
Number of pages11
JournalJournal of Evolutionary Biology
Volume32
Issue number4
DOIs
StatePublished - Apr 2019

Keywords

  • Sceloporus lizard
  • colouration
  • phylogenetic comparative methods
  • sexual selection
  • signal evolution
  • visual communication

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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