Anole Annals

That’s no viper

If there’s one thing we like here at AA, it’s convergent evolution (e.g., 1,2), so we’re always delighted to learn of new examples. Thus, we were delighted to read the recent report on convergence between Australian and North American snake faunas, written by Grundler and Rabosky and now available online at Proceedings of the Royal Society.

Australia is famous for being the only continent on which venomous snakes outnumber non-venomous ones. That is the result of radiation of a single clade of elapid snakes, known as the oxyuranines. It has long been noted that some oxyuranines seem convergent on counterparts elsewhere, such as the death adder, which looks and acts much like a heavy-bodied viper (photo above).

Grundler and Rabosky set out to test this idea of convergence more quantitatively, specifically asking whether the Australian radiation as a whole was more statistically similar to North American snakes than one might expect by chance. That is, does the convergence extend beyond a few pairs of species to encompass the entire radiation–is the radiation-wide degree of convergence greater than one would expect by chance? Alert readers will recall that this is the same question that Mahler et al. recently asked about Greater Antillean anoles, and Grundler and Rabosky used some of the new techniques presented in Mahler et al.

And the results, in a nutshell, are positive. Not only are there many cases of convergence (see figure below), but the overall amount of convergence is statistically significant. This can be seen in two analyses. First, for Australian snakes, the nearest morphological neighbor in North America is more similar than one would expect by chance. Second, Australian elapids have diverged to occupy 10 phenotypic peaks in morphological space, and seven of these are occupied by North American snakes as well.

The paper has three interesting twists:

1. Despite the great convergence in morphology, North American and Australian snakes are not convergent in diet. In particular, the Aussies eat a lot of lizards and snakes, and insect-eating is much more prevalent in North America.

2. There has been speculation in some quarters that replicate adaptive radiation is an island phenomenon, but this study shows that it can occur between mainland faunas as well.

3. Moreover, the convergence spans multiple lineages. Although the oxyuranines are a single radiation in Australia, their counterparts in North America belong to five different colubroid lineages (not that this analysis was restricted to colubroids, which include the great majority of snakes).

I think it’s safe to conclude that snakes aren’t quite as cool as anoles, but they’re getting there.

Battling female Anolis gundlachi. Photo by Ellee Cook.

Territorial behavior in anoles has been extensively studied, but mostly between the males. Yet, females engage in all kinds of aggressive interactions and seem to have territorities. What are the similarities and differences between their behavior and what males do?

Ellee Cook is studying just that in Puerto Rico, focusing on A. gundlachi. She’s in the field right now and has just filed a report on Chipojolab. Among other things, she witnessed a drag-down, knock-down fight, pictured above.

Of course, we’re all waiting to know–is this what females use their dewlaps for?

A blessed arrival. How often do females lay their eggs? Information needed!

We’ve previously reported on a study of seasonal population  reproductive cycles of female A. cristatellus from adjacent shade-dwelling and open-sunny sites being conducted by Luisa Otero, Ray Huey and George Gorman. George writes in to say that they “would appreciate ANY information on egg laying intervals for individual female anoles [of any species] either from captive breeding programs or from field studies. If published,  references are appreciated. If unpublished, access to your data is doubly appreciated. Obviously, if there exist ancillary data on temperature regimes of the egg depositors, that would be even more wonderful.”

Please respond as a comment or write George directly.

Writing in response to an AA post on declining green anole populations, AA reader Ann V. suggests that crazy ants are the cause:

“Here in Bryan, Tx I have noticed a severe decline in anoles in my normally anole-filled yard. I saw them earlier in the summer (in May), but they have all but disappeared now (and I have been actively searching for them). My yard receives a lot of water and even during past droughts, I still had plenty of anoles. I have also noticed two other things. My fire ants are disappearing, but I do now see the raspberry “crazy ants.” I was wondering if the appearance of the highly invasive crazy ants might be a reason why my anoles are gone? (I know they do affect  number of fire ants).  Has anyone else noticed this correlation?”

Photos by Robin Moore that appeared on CNN.com and are on his website.

We’ve previously discussed the threats to Jamaica’s biodiversity, herpetological front and center, but now a CNN opinion piece has brought the issue to the public at large. The article is written by Wendy Townsend who, according to CNN “writes for children and young adults, and she and her family raise lizards as pets. Her third novel, “Blue Iguana,” has just been released by namelos.”

Townsend’s op-ed appears to be based on a fantastic set of posts, videos and photos by conservationist Robin Moore. I highly recommend you check those out at robinmoore.com.

Here’s what Townsend has to say:

“Kenroy Williams, also known as “Booms,” is “Guardian of the Reptiles” in Hellshire, located near the Goat Islands in Jamaica. The region is centered in the Portland Bight Protected Area, an area of ocean and land set apart in 1999 to protect its rich biodiversity of birds, reptiles, plants, trees and marine life.

But now, the Jamaican government is preparing to sell the Goat Islands to the China Harbour Engineering Co. to build a megafreighter seaport and industrial park. China Harbour is part of a conglomerate blacklisted by the World Bank under its Fraud and Corruption Sanctioning Policy.

“They’re destroying what should be preserved,” says Booms, who has been working to protect exceedingly rare reptiles in the area for seven years, including the critically endangered Jamaican iguana.

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Photo by Bob Trivers

Bob Trivers is renowned as one of the most important theorists in the history of evolutionary biology. Less well known, however, is undoubtedly his most important work, on the mating behavior of Anolis lizards. Seriously, his 1976 Evolution paper showing size-assortative mating in the beautiful A. garmani of Jamaica was an important demonstration of sexual selection back in the days before its prevalence was widely appreciated, and his book chapter in the Ernest Williams festschrift on A. valencienni is also a classic*. (note: most of Trivers’ papers can be found on his website)

Bob is currently back in Jamaica and is keeping an eye on the green guanas, as they’re called. He reports:

“Here is the largest male on my property copulating for 34 minutes—impervious to my camera—with a long, slender—dare I say?—attractive female but here is the kicker, two hours earlier he had copulated with another female and so far as I can tell, he used his left hemipenis on the first and the right one on the second.”

Several days later, the same fellow was up to it again: “didn’t think i could get any closer to the monster male, did you? Watched the whole courtship from a distance of several trees and 20 yards; she stayed posing the whole time—beautiful sight—with her whole body off the substrate except the tip of her tail raised in a captivating arc; she never moved once as he traversed the distance dewlap-ing and head-bobbing—she head bobbing sometimes as well.”

Photo by Bob Trivers

Note that the big fella’ has switched sides again, using his left hemipenis this time.

And on the subject of hempenial switching, here’s a summary of what we know about that, from Lizards in an Evolutionary Tree (footnote 174, p.137):

Anoles (at least A. carolinensis and A. sagrei, the only species so studied) alternate the use of hemipenes. Each hemipenis is connected to its own testis. If prevented from using one hemipenis (by placing tape over one side of the cloaca), the male transfers significantly fewer sperm when it continually reuses the same hemipenis (Tokarz, 1988; Tokarz and Slowinski, 1990).”

* Hicks, R.A., and R.L. Trivers. 1983. The social behavior of Anolis valencienni. Pp. 570–595 in A.G.J. Rhodin and K. Miyata, Eds., Advances in Herpetology and Evolutionary Biology: Essays in Honor of Ernest E. Williams. Museum of Comparative Zoology, Harvard University: Cambridge, MA.

Baby Anolis proboscis. Photo by Santiago Ron

After prolonged efforts, Ecuadorian anole maestro Fernando Ayala-Varela succeeded in hatching out a baby horned anole. And break out the blue wrapping paper–it’s a boy! And lo and behold, answering a question we all had, the little fellows have little nubbly horns! Well done, Fernando!

Anolis allisoni from Roatan, Honduras. Photo by Jonathan Losos.

The Museum of Comparative Zoology will soon publish a major monograph on the anoles of Honduras in the Bulletin of the MCZ and we are looking for a photo of a Honduran anole to put on the cover. We’re looking for an eye-catching shot, suitable for presentation in a vertical format. If you have one that we could use, please let me know.

Anolis cupreus. Photo courtesy Mayra Oyervides.

A while back we had a post featuring a photo of Anolis limifrons in full battle mode, tongues sticking out. Check out the comments on that post for discussion of the prevalence of this behavior. One commenter said that he’d seen it in A. cupreus, and now here’s visual proof.