On the importance of Dorsal and Tail Crest Illumination in Anolis Signals

With a flurry of recent attention investigating how background light may influence the signalling efficiency of Anolis dewlaps (1,2,3,4), particularly those inhabiting low-light environments where patches of sunlight appear at a premium, it occurred to me that extended dorsal and tail crests may fall under similar selection. Below are some photos of Puerto Rican crested anoles (Anolis cristatellus) – a species in which males exhibit an enlarged tail crest and the ability to voluntarily erect impressive nuchal and dorsal crests during aggressive interactions (the mechanisms of which are detailed in this previous AA post) – that show how crests may contribute to signalling.

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I have no doubt this thought has crossed the minds of many anole scientists before, particularly those current graduate students so successfully studying A. cristatellus and familiar with their ecology and behaviour (namely Alex Gunderson, Kristin Winchell, Matt McElroy, and Luisa Otero). Dewlaps are undoubtedly of primary importance to anole signalling and communication, but what are people’s general thoughts on the relative importance of other morphological features?

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3 thoughts on “On the importance of Dorsal and Tail Crest Illumination in Anolis Signals

  1. Well, I don’t really see a point for the crests aside from display/signaling (maybe I’m missing it?), but I’m glad it’s finally getting attention!!

    Has there been any studies on the crest size when raised near, or isolated from other males? I. E. Do they put more energy into growing the crest with the presence of other males, or is it purely passed on from the parents?

  2. We did some preliminary work on tail crests years ago (current Harvard grad student Sofia Prado-Irwin worked on this for her REU project). We found larger crests in open urban habitats. We didn’t really have an explanation for this – maybe related to thermoregulation or male dominance/density?

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