A glorious event–the 100,000th viewing of an Anole Annals page—is about to occur. In fact, the very next page to be viewed, perhaps the first person to read these words. I should add that this is the result of 59,425 unique viewing sessions. And almost all of this viewage has occurred in the past year. Whomever’s next, let us know who you are so your name can be inscribed in the AA Hall of Fame.
This is the second round of voting for the best Anole Annals header photo. As reported previously, the winner will receive a signed copy of Lizards in an Evolutionary Tree. On the strength of dozens of votes from visitors arriving at our page from Mexico via Facebook , Ramon E. Martínez-Grimaldo’s photograph of A. isthmicus was the landslide winner of the first round. Congratulations Ramon! Next week we’ll have a final vote involving the top vote-getters to determine the winner.
A. cybotes juvenile. Photo courtesy of Thom Sanger
Apologies for the messiness of the formatting; this is my first blog post, and it only got here with a lot of technical support from JLo! History is full of examples of the little guy getting left behind. Unfortunately, so is the study of anoles. Most anole studies focus on adult lizards, and while there is certainly much to be learned from adult-focused studies, to ignore juveniles is to cheat ourselves of a great opportunity to better understand Anolis life history.
A. cybotes juvenile. Photo courtesy of Thom Sanger.
As readers of this blog likely appreciate, anoles are a model system for understanding evolution. To gain a comprehensive understanding of the factors that led to their stunning diversity, it’s important that we understand how selection acted upon these lizards at all stages of life – not just adulthood. A lizard has to survive from hatchling to reach adulthood and until we know more about how juveniles interact with their environment we cannot determine whether selection has shaped the juvenile stages with the same intensity as it has adult traits.
Thom Sanger wrote an earlier post that discussed the growth of Anolis limb length: “Growing Limbs – But Not the Kind With Leaves.” According to his post, variation in adult limb morphology can be traced “all the way back to the point in development when the cartilaginous long bone anlagen are just forming.”
This past summer, I worked with Thom, Michele Johnson (Trinity University), and Trinity undergraduates Ellee Cook and Diego Castro to study the morphology and behavior of juveniles on grounds of the Coral Sol Resort in Barahona, Dominican Republic. My goal was to understand whether juvenile lizards behave similarly to adults and whether juveniles have the same body proportions as adults.
As Jonathan describes in Lizards in an Evolutionary Tree (Chapter 8 ) data on anole food preferences are sparse. However, this is a critical element of anole biology that needs to be more thoroughly explored if we are going to understand the diversity of skull shapes (the topic of a future post), nutrition, or energetics in anoles. The question is simple in principle but difficult in practice: do species preferentially eat certain insects? If so, has head shape adapted for the preferential capture or mastication of insects of a particular size or hardness? Do lizards that eat insects of lower “quality” eat more often or move less often? Perhaps anoles will eat what ever bug it happens to encounter and skull diversity is the result of other selection pressures. At this time we do not yet know. Interestingly, however, preliminary evidence suggests that the primary food source of many anoles are just ants, which while quite abundant are not very nutritious. Ants can account for up to 80% of the stomach contents of A. distichus for example.
The embedded video gave me an idea for a great experiment that can be done in a controlled setting. Simply run various bugs across the screen of an iPad and see if different species preferentially target particular sizes or shapes. If anyone would like to donate an iPad to this cause of utmost importance I would be happy to perform the experiments.
Check out what Janson Jones has to say about the largest anole, as well as a cool video, here.
Here’s a close up of the Anolis hendersoni I found sleeping one fateful night inside the Dominican Republic.
Anolis hendersoni - male
Prior to finding this species, I had spent the evening looking for Sphaerodactylus armstrongi and S. streptophorus on the northern slopes of the Sierra de Bahoruco NW of Puerto Escondido. Upon entering a patch of closed-canopy, broad-leafed forest with a dense, bushy understory, I remarked to myself, “I bet there will be Anolis bahorucoensis here.” Anolis bahorucoensis is a bush anole that is common across the Sierra de Bahoruco, and often found alongside S. armstrongi. I was not expecting to see A. hendersoni – another dolichocephalic bush dwelling species that is closely related to A. bahorucoensis – because it is generally considered a Haitian endemic whose range doesn’t cross the border into the Dominican Republic. When the sun set and I switched over to night hunting, I was happy to find out my intuition was, for once in my life, a close approximation of reality.
The core of my dissertation involves assessing genome-wide patterns of gene flow during anole speciation. For a variety of reasons, I ultimately want to acquire DNA sequences from throughout the genome. As a first pass, however, I’ve been using Amplified Fragment Length Polumorphisms (AFLPs). As a molecular technique, AFLPs are experiencing a comeback of sorts [1] [2]. Popular in the early 2000’s, AFLPs went out of favor as Sanger sequencing became cheaper and easier. The resurgence AFLPs has largely been due to the realization that evolutionary patterns often vary throughout genomes and therefore methods that survey as much of the genome as possible are preferable to those that look at one or a few regions.
The cavalcade of new anole species continues with Gunter Köhler’s description of a new species, related to A. altae, from Costa Rica. The last few years have seen a steady progression of new species descriptions, almost all from Central and South America. Anolis must be pushing 400 species by now. Anyone got an up-to-date total?
And who’s described all these species? Rich Glor is in the midst of a five-part series identifying the big guns in Caribbean island species descriptions, but I reckon the mainlanders have been described by a very different crowd. Certainly in recent times Köhler, Poe and others must be up there, but it would be interesting to see who historically has been the most prolific. Perhaps a job for someone from Team Norops?
In any case, down to the nitty-gritty. What used to be known as A. altae has been divided now into seven allopatrically-distributed species at high elevations in Costa Rica.
Our Anole Annals header photo contest has elicited some rather spectacular entries. Narrowing the field to a manageable number of entries for voting was no easy feat and was achieved largely be excluding entries that were improperly sized. There were too many good entries to reasonably fit all of them into a single poll, so we’re going to vote for the grand prize winner of the signed book in two rounds. Here’s the first round:
More details on the contest after the jump.
A highly technologically advanced egg-laying location: a used bulk-size yogurt container (generously donated by various staff in the department) filled with moist vermiculite. In this case the lid is removed so that you can see the vermiculite inside.
While Anolis distichus may have plenty of options for where to lay eggs in the field, we needed to do a bit of experimentation before landing on a good place for them to lay their eggs in the laboratory environment. Other anole facilities tend to allow their lizards to lay eggs in the soil of potted plants, and we originally had our lizards laying in the soil substrate of their cages. However, eggs that spend time in soil tend to desiccate quickly, sometimes even before they’re discovered. Given that we knew our production would be limited, we wanted to avoid this risk during our breeding experiments. We arrived at a solution that is a combination of breakfast and gardening: yogurt cups filled with moist vermiculite.