Anole Annals

Trapelus flavimaculatus displaying.(above photo does not quite show dewlap at full extension). Photo from http://elsanaumann.wordpress.com/2013/05/02/amazing-agama/

Quick—when you think of an agitated anole, what’s the first thing that comes to mind? Perhaps a quick color change, maybe even some squeaking and biting and, of course, a couple flashes of the dewlap all may have been high on the list. Well, not to be outdone by its cousins from the new world, the Middle-eastern yellow-spotted Agama (Trapelus flavimaculatus)  has come up with a spectacular display that involves all three behaviors listed above.

Now while its true that when it comes to agamid dewlaps, this species is not as well endowed as a few others (Hypsilurus and Draco come to mind), no other agamid (to my knowledge, that is) displays quite like it. First off, the lizard changes  from its usual drab brown coloration (essential for a desert dwelling lizard)  to a  light cobalt blue while its ordinarily pale yellow tail glows neon orange. Next, the lizard opens its mouth and displays the bright orange inside of its jaws while making a hissing noise.

yellow spotted rock agama- regular coloration. photo from http://www.treknature.com/gallery/photo71341.htm

The final act to this performance comes when the lizard extends its deep cobalt blue dewlap at the attacker. As soon as the threat is gone, the display is over and the lizard resumes its usual coloration. These lizards also use this display as a means of attracting/advertising their presence to females, so that’s another thing they might have in common with Anolis (I’m not exactly sure if the Anolis dewlap actually helps attract females). I thing it’s interesting that while anoles turn darker to convey agitation, these lizards actually become brighter. I think this has something to do with the fact that these are desert lizards and the blue color is really more in contrast to the desert  environment.

On a related note, how many other lizards out there have the ability to change color based on their mood?

Everyone (who reads this blog) knows that anoles are one of the most fascinating groups of organisms on the planet. We also all know that this makes them a remarkably popular lizard genus to study, a topic that Rich Glor has addressed on this blog previously. However, while dominant in some fields (and meetings, like Evolution or SICB) anoles scarcely make an appearance at others (ESA, IBS). This raises the question of whether anoles are really as popular as we think? How do they stack up to other sexy taxonomic groups like mammals, birds or bees?

A recent tweet and blog post by Chris Buddle from McGill gives the basis for an answer. He used a (quick and dirty) Web of Science search to find the number of publications per species within 15 haphazardly chosen Orders, merging these into higher taxonomic groups for visual comparison:

Originally from: www.scilogs.com/expiscor/biodiversity-bias-the-relationship-between-taxon-diversity-and-research-publications

Buddle showed that research publications are strongly biased toward mammals (no surprise there), then herps, then birds (I admit, a priori, I thought 2nd and 3rd would be reversed). However, the obvious question which jumped to my mind (and, I’m sure, to yours) was: how do our favourite dewlapping demons compare? A quick search on Web of Science with search string ‘Anole OR Anolis’ (yes I could have gone with anol*, but this picked up a few thousand extra hits for anolyte) gave approximately 12,686 hits. Using The Reptile Database‘s number of 393 anole species (cue argument now), I roughly mapped the anole results on to Buddle’s plot:

Modified from: www.scilogs.com/expiscor/biodiversity-bias-the-relationship-between-taxon-diversity-and-research-publications

Anoles win! Perhaps not surprisingly, anoles are remarkably well studied given their diversity, at least compared to other groups defined at the Order level (keep in mind that, because publication intensity is uneven within taxa, averaging across a more diverse group will tend lower the numbers). Nonetheless, anoles annihilate the carnivores, which Buddle highlights as the most studied order with a publication to species ratio of 7. However, let’s not forget that the vast majority of these studies are on sagrei or carolinensis, so there are still hundreds of under-studied anoles (and really, can a species be over-studied?)

Lastly, before we get too smug about the popularity of our exalted study genus, with its publication to species ratio (pub:spp) of 32.3, I did a quick look at the numbers for the genus Parus. This genus (even after lumping it in with Poecile, Cyanistes, Lophophanes, and Periparus) had a pub:spp = 327.1. And within the herps? Well, Sceloporus clocks in at 85.7. And Xenopus‘ pub:spp is 12451.3! Of course, Xenopus’ ratio is heavily influenced by biomedical research. Also, as I mentioned above, the uneven study of species within genera means averaging over a diverse genus like anoles will drag down the ratio, compared to less diverse genera like Parus, Sceloporus, or Xenopus. Even so, while anoles are clearly very popular, we undoubtedly still have a lot of work still to do.