Ten Animals that Are Smarter Than You Think

Evermanni is back in the spotlight.  The Daily Planet, a science TV magazine that airs on the Canadian Discovery Channel, has joined the growing group of anole fans. This week a video clip of A. evermanni was included as part of a segment "Ten Animals that Are Smarter Than You Think." Evemanni was number nine on the list, a questionable ranking. However, the group included some of the who is who in cognition research, including: chimps, kea parrots, honeybees --the model system of Karl von Frisch, one of only a handful of ethologist who has received a Nobel Prize -- and B. F. Skinner's favorite experimental animal, pigeons. Kudos to Maria Campano for a wonderful job filming. More information on the cognition of A. evermanni, including a link to the original paper, can be found at this post.   

This is also a good opportunity to share our improved "Chipojo Cognition Center" which keeps expanding at a steady pace. If you have any suggestions of an acronym for our room, please let us know.

Chipojo Cognition Center 

Featured Photo

Our picture of Anolis cristatellus has made its way to the slide show of featured photo for the issue at the American Naturalist website.  

Signaling environment from an anole perspective

The Anolis dewlap is a recurrent topic of discussion on Anole Annals. This is not surprising considering that it is commonly view as playing a role in many aspects of social interaction, including species recognition and even sexual selection. Although, I am unaware of empirical studies supporting sexual selection, in the context of female choice.

A recent post by (Ian Wang) asked the question, "Does This Dewlap Go With My Signalling Environment?”   In order to answer this question I would encourage the readers of Anole Annals to have a discussion of what is really is an "anole's signaling environment."  

The paper by Ng et al. (2012) presents some interesting results, and I would encourage everyone to read this paper. The amount of data presented in this paper is impressive, with the authors combining molecular, dewlap reflectance, and satellite data (i.e., GIS data), to evaluate if there is a relationship between dewlap traits and climatic variables across populations of A. distichus. As the precision of GIS data increases, the ability of exploring questions at a finer geographical scale is becoming more common. This paper nicely illustrates this approach. Additionally, A. distichus is a nice system for the study of dewlap variation. In fact, in my opinion, one of Al Schwartz (1968) best anole monographs describes all sorts of geographic variation in the distichus complex. This monograph is a must read for all Anole Annals fans, with beautiful plates and a lot of natural history data.

One of the main findings of Ng et al. is that geographic variation in dewlap coloration is correlated with the "habitat types" in which populations are found. Interestingly, habitat type seems to have a stronger signal than geographic or genetic distance between populations. I have to admit that I am biased, but this is music to my ears. However, before we jump into further conclusions, I feel that it is important to take a step back and evaluate the question I posed at the start of this post – namely, what is the "signaling environment"?

Trying to figure out the correct way to measure the signaling environment has kept me up for many, many nights. Based on what we know, the signaling environment is not simply the “forest type” or degree of vegetation cover, which at this stage is the type of information that can be extracted from GIS data. Those variables are too coarse to provide a proxy for the signaling environment. From the perspective of an anole, the signaling environment is much finer, on a scale that can account for variation in signaling environment within a single “habitat type”. For example, within a moist forest there can be multiple signaling environments with regard to light levels, as we have demonstrated for Puerto Rican anoles (Fleishman et al 2009). In a similar vein, both A. cooki and A. cristatellus inhabit xeric forest, and their signaling environments are different (Leal and Fleishman 2002).

 

Anole Signaling Environment

But, does this mean that if we measure light intensity (i.e., irradiance) alone, we are done characterizing the signaling environment? The short answer is no. There is also a chromatic component to dewlap detection, which means that we need to know not only the intensity of the light, but also the color shape of the background (i.e., radiance). I would like to raise a word of caution and suggest that for now GIS data might not be a feasible approach to addressing questions of dewlap evolution as it relates adaptation to "signaling environment". 

Also, I have learned the hard way, what makes a dewlap brighter or darker is not its reflectance. Although the light reflected off a dewlap has an obvious contribution to overall brightness, the largest contribution typically comes from the amount of light that is transmitted through the dewlap.

Going back to the paper by Ng et al, this is an interesting first step and can serve as a springboard for further research. But for now, I believe that when using coarse measurements of habitat type, the jury is still out with regard to the effect of “signaling environment” on dewlap diversity. A logical next step for this type of approach should be to evaluate whether data collected at the micro-scale, which at the moment is our best proxy for what is relevant to the lizard's "signaling environment," offer similar results to those provided by the large-scale data used in their study.

Finally, the dewlap is one the coolest traits of anoles, and compared to all the work that has been done in anoles, it is mind-boggling that we know so little about its function. This includes a lack of experimental evidence to support the widely common view that the dewlap is used during the process of sexual selection. Unless sexual selection is used in a broad fashion (see Leal and Losos 2010 for discussion), it might be premature to discuss the role of sexual selection in dewlap evolution.

"El que ríe ultimo, ríe mejor"

After a very long and tortuous path, our paper on CTmin finally came out today in The American Naturalist. If you are interested in reading it, here is a pdf. This is one of those studies that requires an in-house description to fully appreciate its content, particularly because two of my friends were critical players in the story of this project’s development. As they did their best to convince me that it was not such of a great idea to expend energy on this study.

Ray Huey and Manuel Leal at the Anolis Symposium

 A long time ago, I told Alex that we should measure CTmin (the lowest temperature at which lizards can maintain coordination) for the introduced population of A. cristatellus in Miami. His response was along the lines: "Ray has shown that the physiology of lizards is relatively rigid, so why should we waste our time?" I tried to convince him that Miami is cold for a Puerto Rican. Being from Minnesota, he was not convinced. I then mentioned that anoles sleep on top of vegetation, usually leaves, which probably limits their ability to escape cold weather. But, that was not good enough for him either. This should not be surprising because he seems to be predisposed to reject my ideas. Finally, I approached Ray, and asked him the same question. His answer was similar to Alex's: “Physiology is very rigid. Why are you going to waste your time?”   

Although, both of my attempts to get my friends on board with this project failed to produce a positive response, I decided to go ahead and prove them wrong, in part, because one of an advisor’s jobs is to keep the students (Alex) humble. So, after a few more discussions, Alex agreed that I would bring A. cristatellus from Miami (he was not going to waste his time) and that we would measure CTmin to compare to his data from Puerto Rico. In March of 2010, I went to Miami to collect a series of individuals of A. cristatellus. Nearly two weeks after collection, Alex and I got together to measure CTmin. Because Alex was still so skeptical, we decided to make a friendly wager, which is commonly in the form of a free lunch or dinner in our lab. If lizards from Miami had a lower CTmin than lizards from Puerto Rico, Alex would treat me to a nice lunch; however, if Alex was correct, I would be treating him to several lunches (needless to say, I felt that this was money in the bank). After measuring a few lizards, it was clear, the individuals from Miami were active at temperatures at which individuals from Puerto Rico were like popsicles. Below is the original graph, which got me a free lunch and which was of the first version of this paper when it was submitted to review. 

In a nutshell, we found differences in CTmin between populations. After collecting data on CTmin during the fall, we submitted the MS. However, although both reviewers found the manuscript promising (see below), they asked for additional data, including CTmax for both populations.

REVIEW SUMMARY

" To summarize, this is a promising study that suggests that (i) cold tolerance has diverged genetically between populations of lizards in merely 30 generations, and (ii) that thermal changes can result in rapid evolutionary responses in tropical species. If the authors could provide the additional data required to solidify these suggestions, a revised manuscript could make an important contribution."

We moved forward and collected the additional data, some of which is shown below in a new figure.

Figure 2 from paper, showing differences in CTmin, note the values are the same as those of the original figure.

In the end, this has turned out to be an interesting story. It is one of those cases in which the results are what you should expect when you "think like a lizard". On one hand, Ray is correct -- physiology seems to be relatively rigid because behavior buffers the lizards from selection. But for a sleeping anole, over a leaf in a winter night, behavior is not such a useful buffer. Thus, we might have found the Achilles heel of behavior. It has also provided the opportunity for Alex to reflect on his initial viewpoint, and to learn that maybe once in a while it is ok to listen to your advisor.  So it turns out that "el que ríe ultimo, ríe mejor"

Media coverage

 

Phys.Org
Conservation Magazine
Science Daily
Times of India
The Hindu
Vancouverdesi

a few more days

just need to wait patiently until it's time for the anole to head to bed ...

Greetings from sunny Costa Rica!

(Just kidding, it's raining.)

Hey there. I’m in Costa Rica for about a month & figured I’d give a quick update. I’ve been out filming anoles at La Selva Biological Station (OTS) with some level of success.  Over the next couple weeks, I’ll periodically post some videos (they are – not surprisingly – difficult to upload from here). For now, a photo or two & a story will have to suffice.

A few days after I got here, I recorded a juvenile male capito (~38 mm snout-vent length; see above). After I captured him by noose and grabbed him with my hand, he regurgitated his last meal … and it was still alive! As you can see below, the larva was relatively large. I should note that after 24 hours it had “shrunk” back down to a length of 28 mm, but that’s still not too shabby for such a small lizard!

P.S. Always check your camera case for bullet ants before picking it up.

Bucking the Trend

Convergent evolution has become the trademark of West Indian anoles. Species occupying distinct structural niches exhibit high levels of convergence in morphology (e.g., similar body proportions and general shape), ecology (e.g., habitat selection) and behavior (e.g., foraging and movement patterns) -- what are referred to as ecomorphs.  Decades ago E.E. Williams & colleagues began their studies of ecomorphology and convergence in anoles across the Majar Antilles, and this topic continues to be an active area of significant research. At the present, with the exception of aquatic anoles, convergent evolution has been found across many traits from morphology to physiology… but the run seems to have come to an end.

     To make a long story short, I was able to convince Brian a while back that a study of brain evolution in anoles was an easy, low-hanging fruit. In other words, it was ripe for the picking. Initially Brian seemed more interested in the evolution of "play" behavior in lizards, but I was finally able to persuade him that I was ignorant about that subject so he should wait to "work play" for his postdoctoral research. Well, a few years and hundreds of hours of tedious work later, Brian has completed the first study addressing brain evolution in anoles (and one of only a handful of studies of brain evolution in reptiles). Needless to say, the fruit was not hanging that low ... it was much closer to the canopy!!!

What appears to be a low hanging "pana" but look closely and there are many more near the canopy

There are a few shelves like this one, packed with brain sections

   Brian's findings are reported in a paper recently published in Brain, Behavior, and Evolution (pdf here). The results show an absence of convergence in brain size between members of the same ecomorph class. In fact, there were no differences between ecomorphs in either overall brain size or in the size of major brain structures after correcting for body size and phylogeny. This is a surprising finding because the brain is often considered to be the substrate upon which selection might act to shape differences in behavioral traits that are commonly reported between ecomorphs. This raises the question, why does the brain buck the trend and fail to exhibit convergence? One possibility is that convergence is present at a finer scale, such as neuron density or connections. Alternatively, we are only beginning to scratch the surface of that big black box called the brain, and it is highly likely that once we learn more about the complexity of the box, we will realize how naïve we were with our early predictions.

Two Seconds of Fame

Anoles are a well known model system for studying evolution, which is why anoles are commonly found in textbooks to illustrate a diversity of evolutionary processes. I am happy to say, that finally, they got their TWO SECONDS of fame as a system for studying animal behavior. Below is a short clip from the well known Canadian TV Documentary Series "The Nature of Things" in which anoles were presented shoulder-to-shoulder with the most common key players of this type of TV documentary. All I have to say, chimps and/or crows beware, a lizard might be taking your spot soon.

Below are a few pictures documenting the behind-the-scenes action that took place during the filming of the lizards by CBC. This was my first experience dealing with television cameras, and believe me when I say it was a long day. The crew was great, but talking to a gigantic camera that is pointing right at your face was a nerve-racking experience. It was amazing how much equipment was brought in and how much filming occurred at our lab in order to produce the few minutes of final product that are shown in the documentary.

CUT!!!!!! Manuel, can you please walk more slowly and open the cage really slow

CUT!!! Manuel, can you please explain what you did again, this time try not to mix Spanish and English

7th World Congress of Herpetology (B)

If you are interested in the possible mechanisms shaping the evolution of lizards' brain, you must be at Ace's talk tomorrow (Brian Powell, at 2:30, at Irving K. Barber 195). The slide below illustrates the two main mechanisms that he will be discussing, using the anoles of Puerto Rico as a model system.  

Otra Vez

Today, "El Nuevo Dia" published a nice article covering our recent study on the possible impact of climate change on Anolis cristatellus throughout its range in Puerto Rico (pdf can be found here). For those brave of heart, you can watch one of the most  awkward conversations ever recorded to see us discuss the findings of the paper.

7th World Congress of Herpetology

Hi from Vancouver, Canada. The 7th World Congress of Herpetology began today, and the Chipojo Lab is nicely represented by two of its best (looking) members, Dave Steinberg and Brian Powell. This meeting brings together herpetologists from around world (more than 1600 registrations), and it is characterized by a humongous number of talks and posters covering a diversity of research topics. Tomorrow, our own Dave will take the podium to rock the evening session by presenting his work on the modulation of signal properties as a behavioral mechanism to optimize signal detection.  All I have to say, if you are in Vancouver, you should not miss his talk. Please stay tuned for updates from British Columbia.

Dave practicing his talk

Versatile Gizmo

We are very pleased with of our portable laboratory. Below is a series of pictures showing the different places where we have set-up our dewlap holders during this trip. We have had a lot of fun moving from site to site, and I am very proud of the fact that I have designed such a versatile gizmo. Best of all, our species sample size continues to increase with each trip. In the past few weeks we have added three new species to the "color space," which gets us so much closer to our goal of having at least 22 species in our study.

El Verde Field Station, Puerto Rico

Frederiksted Hotel, St. Croix

Parador Boquemar, Boqueron, Puerto Rico

"Gelb Effect" II

Last summer I posted a picture of Anolis lineatopus that illustrated why accounting for transmission is critical when addressing questions related to signal detectability. Considering transmission is particularly important in the case of signals, such as the dewlap, for which transmission contributes greatly to the "perceived" brightness of the signal and the sudden increase in brightness, which is known as the "Gelb Effect". The dewlap of Anolis acutus is also a great example of the "Gelb Effect" as illustrated by the picture below. In A. acutus, the effect is even more dramatic because the white region of the dewlap is at least twice as transmissive as the yellow/orange portion of the dewlap.

Nosy Goat

I have previously posted on the many problems we occasionally face while collecting field data, from poison-wood to swarms of sand-flies.  However, this is the first time that we had a close encounter with a goat. Yes, a G-O-A-T! As seen in the photo below, Elise engaged in hand-to-head combat with a goat that wanted to take a bite out of the spectroradiometer and fiber. After a few tense seconds, Elise was able to keep the animal under control and collect the data.

"Elise vs Goat"

Back to Puerto Rico!

Tomorrow we travel from the island of St. Croix to the El Yunque forest of Puerto Rico. That means so long (for now at least) to Anolis acutus, but an eager return to some other species, including A. evermanni.

As someone who’s seen the dedication & care with which Maria (AKA ‘mama Maria’) tends to the Leal lab lizards at home, I’m excited to report that she will soon receive more evermanni individuals. Once we’re in Puerto Rico again, we hope to collect some to send to her! Among the experimental possibilities, these lizards are likely subjects of future (lab-based) tests of pattern discrimination abilities & color detection. 

A Dissertation Must Be Brewing

Hola from St. Croix. Today we were out collecting habitat spectral data for Anolis acutus. Acutus has a beautiful dewlap, nice body color, and elegant body shape. Such a combination of traits would give bragging rights to any lizard. However, their social structure has my head spinning. As pointed out in a series of papers by Ruibal and Philobosian in the early 1970's, you can easily find multiple males in close proximity -- it is common to see a tree with 5 to 8 males -- and to observe relatively little, if any, fighting. It's quite surprising to see males walking by each other and not witnessing any signs of aggression! Clearly, these guys have not read the chapter on territoriality by J. Stamps!!!! It seems that the time is ripe to revisit some of the ideas proposed by Rubial and Philibosian about A. acutus's relatively "strange" social behavior with a fresh pair of eyes.

"another day at the tree"

Island Jumping

Today we are leaving for St. Croix in search of Anolis acutus, the only species of anole that occurs on the island. Leo and I predicted that dewlap spectral properties should represent an "optimum" phenotype for maximum detectability in the case of "single-species" islands. By tomorrow we should know how wrong we were ... AGAIN!

Elise está muy triste!!!!!!