The Anolis literature is replete with examples of lizards altering the properties of movement-based displays in response to fluctuations in environmental conditions. Anoles modulate head-bob amplitude based on social context (Fleishman 1988) and social spacing (Stamps and Barlow 1973, Steinberg & Leal 2013), and head-bob speed based on background vegetation motion (Ord et al. 2007) and many other habitat variables (e.g., Ord et al. 2010). Our recent paper adds predation pressure to this growing list of factors that might affect the signal properties of anoles.
We found that male Anolis sagrei on islands with predatory curly-tailed lizards gave head bobs with much smaller amplitudes than anoles on curly-free islands (check out these examples of moderate and high amplitude displays). This reduction in amplitude limits a signaler’s visibility to predators, but also to other anoles. If you are bored, you can imagine various scenarios in which this might influence male reproductive success and possibly even social dynamics. Such scenarios remain to be tested, but could be pretty fascinating.
Manuel Leal’s post on the Chipojo Lab blog provides a more detailed discussion of the paper. He points out some interesting questions that could be addressed with future studies.