Experimental Natural History

Those that follow the Chipojoblog are familiar with my motto “I strive to become a naturalist.” This motto reflects my view, and the approach used in my lab, that developing an intimate understanding of the ecology and behavior of the organisms we work with is an integral part of our research program. The majority of our "posts" are done with the objective of sharing our observations, made under natural conditions, of the behavior or ecology of anoles, what is commonly labeled as natural history. These observations are extremely valuable as they formed the building blocks for the exploration of new hypotheses.

   Our most recent paper, co-author with Leo Fleishman, and recently published on Functional Ecology “Whydo Anolis lizard dewlaps glow? An analysis of a translucent visual signal” is a prime example of this approach, in which detailed observations of an organism's general ecology are examined within a theoretical framework to yield novel hypotheses: what I called Experimental Natural History.

   In the case of this paper the observation happened a long time. So long, that at the time I was a graduate student finishing my work and getting ready to move to Leo’s lab. I was in Cuba collecting data on the ecology of anoles, particularly the community of anoles at Soroa. While at Soroa, I filmed the display of a few species of anoles, including A. homolechis. Anolis homolechis is found in partially shaded forest and has a white dewlap. As shown by the video, the dewlap of A. homolechis appears to “glow.” This effect is so dramatic that the dewlap stands out against the background, giving the impression that it is a light source.

Video of a male Anolis homolechis

   When I showed the above video to Leo, he was so impressed that he suggested that we should evaluate the possibility of “fluorescence”, that is, the short wavelengths striking the dewlap were being absorbed and re-emitted as longer wavelengths, thus giving it the perception of a “light bulb”. To make a long story short, that was not the case, and in the process of testing this idea I learned that although lasers are commonly described as monochromatic they are not. In the majority of the cases laser also emit a longer wave peak.

   This was the end of the potential “fluorescence” effect, but not the end of our quest to understand the mechanism by which dewlaps are able to appear so bright, and if those mechanisms have potential consequences in the ability of the receiver to detect the signal. We conducted a second experiment, showing that light geometry highly contribute to this effect. Below is an illustration of our gadget to test this effect. Basically we simulate the "sun" striking the dewlap from different angles and measured, from the front of the dewlap (reflection) and back of the dewlap (transmission) and measured the radiance spectrum of the dewlap A pdf of the paper entitled "Illumination geometry, detector position and objective determination of animal signal colours in natural light" can be found here. As a side note, this paper is somewhat technical, yet is packed with ideas and a must read for those interested in visual ecology.  

Schematic of our gadget to evaluate the effect of light geometry
on dewlap reflectance and transmission

   In a nutshell, dewlaps are quite thin, and not only reflect the light that hits their surfaces, for many dewlaps there is a significant contribution from the light that passes through the dewlap from behind it. This is completely dependent on the light geometry and when transmission is higher than reflection dewlaps tends to appear brighter. But the key finding of our experiment was, that as the light passes through the dewlap the light rays are scattered in all directions from the surface, resulting in a diffuse transmission. This finding allowed us to propose that in order to predict that dewlap coloration under natural conditions both the reflection and transmission spectrum must be measured and that light geometry can be a major contributor to the appearance of a signal.

Male Anolis lineatopus from Jamaica. Note how the dewlap coloration is dominated by light striking the dewlap from the back, that is, the dewlap is scattering the light rays in all directions to appear "translucent"   

   In this paper we showed that the properties of the dewlap to transmit light and to do so by scattering the light rays in all directions, (i.e., to appear “translucent”) greatly increase the signal to noise ratio. The translucent properties result in a signal that is easy to discriminate against the background, by decreasing the amount of noise present in the signal. The figure below illustrates this effect: NOTE how the volume of the red sphere is reduced when light transmission is included in the calculations of the spectral volume of the dewlap (figure b). Also, note how the dewlap doesn’t overlap with the background coloration. The green sphere represents the background coloration.

Two of the panels of figure 4

   If “a picture is worth a thousand words” I encourage you to see the following video (https://youtu.be/errevFcr01k) which is worth at least twice as much; KUDOS to Holly Steinberg for the masterful narration and to Dave Steinberg for the editing.

   As a naturalist I hope this paper illustrates the value of natural history. Moreover, it give you a taste of what I called “Experimental Natural History” when observations of an organism's ecology are examined within a theoretical framework, usually by integrating multiple fields, to yield novel hypotheses. If lucky, those novel hypotheses can open new areas for further studies. In this case, transmission is not limited to dewlaps, other signal structures such as fish fin, insect wings, and feathers are also capable of transmitting light. How important is transmission for the efficacy of those signals remains an open question waiting to be tested.

Ortiga, Anchors, and Deborah's other adventures

This post was written by Deborah López Nieves, and the photos are hers.

                

            Hello everyone! My name is Deborah López Nieves and I am a Natural Sciences student majoring in Biology at the University of Puerto Rico in Aguadilla. 

Deborah braves the river rocks for a photo op!

Well, the reality is that I thought this was going to be a summer like any other ... but months before, Ph. D student, Ellee Cook gave me the opportunity to work as his assistant for a month in El Verde Field Station.  The best thing about this opportunity was that I would be working doing what I like, that is working with reptiles (specifically A. gundlachi). The reality is that I was nervous all this time, waiting for the arrival of the day. When July 15 came, the adventure began early and the excitement. I went for the first time that day to El Yunque (believe it or not, I've always lived in Puerto Rico and had not been to El Yunque) and in the evening I had the opportunity to know who would be my leader for a month and my partner (Ellee Cook and Karen Patterson).

                  The next day began the adventure! Ellee gave us a training on how to recognize a A.gundlachi from the other species and showed us a species I always dreamed of seeing, the A. evermanni (I got excited when I first saw it!). In addition, we were taught to tie knots for our Pole pan fish.  She then proceeded to explain the task we would be working on and the other things we would be doing this month.  The first week and I think part of the second, were captured lizards in 6 different plots. We seized them and Ellee weighed, measured and marked them with a tag (used for marking bees) to finally set them free. These tags helped us to identify the individuals that we would be observing during this month and to know which trees they lived on so then we could record their behavior through observation.  I remember the first day Ellee handed over the observation binoculars so we could identify the color in a long distance and the number of each tag to know what lizard we were looking for. But you know what?! Surprise!!!! Binoculars were not helping and we couldn’t see them! We could’ve been very close or far away and still there was no way we could identify them. I think Ellee thought we did not know how to use the binoculars until she tested them herself. She immediately asked if we could go buy new ones (which became another adventure). We ventured into new sites in search of new binoculars which ended with my car with an empty tire! Besides the flat tire, the important thing was that we got the binoculars and they were good! We practiced for about an hour with the binoculars by using the tags we used on the lizards on a paper we hanged in the wall. The next day we were equipped and ready so we started the observations.

Deborah's favorite plant (or not) - stinging Ortiga! 

                  During this time we had the opportunity to observe the behavior of both females, males and young ones( A. gundlachi ). There were some gundlachi females with which I grew fond off, because they were the most active and to observe them was an adventure. Some were very territorial, while others were engaged on just eating and watching everything around them. There were babies that made me scream with excitement when they were doing their first push-ups in front of me or when they hunted a tiny spider moving quietly through her web (They were cute!). And how could I forget a female which was almost impossible to catch and mark. Once marked you could not see her and for that reason I named her Houdini (because she always managed to escape when I saw her at a long distance). And guess who I saw in my final days of observation ... Nothing more and nothing less than Houdini. After seeing her, and how well she was I was very happy and relieved so I think I can leave El Verde at peace. Certainly, I think it was one of the most exciting moments during this month.

Deborah found an anchor in the forest!

                  This most definitely is an experience I will always remember as it gave me the opportunity to learn new skills that would help me in my future at university level and to define a little more I want to do in the future. I am very grateful to Ellee for giving me the opportunity to be a part to her team and for teaching me many new things. In addition, I am very grateful for making this summer different from others. I'll miss them.

Snails, Leaves, Lizards oh My!

This post was written by Karen Patterson, and the photo and video are hers.

Hello! My name is Karen and I am a senior biological sciences major from the University of Missouri. I ventured on this excursion with Ellee to study the behavior of female anoles with an emphasis on aggression and territoriality. All I can say is WOW. What a trip this has been! We’ve had our fair share of hurdles to jump but I’ve experienced so much! 

One of Karen's favorite leaves!

Up until our arrival, I was having slight difficulties imagining what field research would be like. I had read articles Ellee sent me conveying similar experiments and methods related to what we would be doing, but I couldn’t quite piece it all together to form the big picture. Fortunately, Ellee was very accommodating and eased us into the world that is field research. Day one proved to me that beginner’s luck is real. I caught 14 lizards that day and a wimpy 3 the next. Our first day of data collection began with me being ashamed of not being able to use binoculars correctly…until Ellee asked to borrow mine and quickly reassured me that it was them, not me. This of course led to our fun filled day out in town which a previous blogpost recounts. I found that I enjoyed taking locations of lizards because it was like a game of “I Spy”, or “Where’s Waldo?”. I also confirmed Ellee’s sentiments that lizard watching requires a comfy rock. Surprisingly, there is such a thing…at least for 20 minutes. I learned to eat my lunch without actually touching my food and different ways to reference lizard locations on trees. These included phrases such as “approximately 4 inches below the white spot” or “3 inches above the snail”. Speaking of snails, I discovered I have a slight fascination with them. As Ellee says, I’m probably going to quit my aspirations of attending veterinary school to go get my PhD in snails. On multiple occasions, she would catch me taking time-lapse videos of poor little snails trekking across a branch or sliming across a rock…or me simply taking pictures of them “kissing”. 

One last obsession…leaves. There were some pretty spectacular ones (see photo above). Being out in the field all day is definitely a completely different experience than being behind a microscope in lab. I’ve found that I enjoy aspects of both. The chairs in lab are more comfortable than rocks and I enjoy the mosquito free surroundings. However, unexpected findings in the field are pretty neat…except when they’re spider webs that you find with your face.

My favorite part of this trip so far has been watching a female A. stratulus dig, turn around, squat, lay an egg, and bury it! What incredible timing did we have to witness such an event! I’ve also enjoyed our many trips into town. Whether it was for groceries, eating out for dinner at El Verde BBQ, or walking along the Luquillo Kiosks, I always seemed to experience a different side of Puerto Rico. Shopping at the grocery store enabled me to see familial interactions while eating at El Verde BBQ allowed me to experience real Puerto Rican cuisine. The Luquillo Kiosks were an experience in itself, filled with music, people dancing and the epitome of casual relaxation. Interesting enough, it was my first time seeing people camping on the beach; something that is apparently common around the 4^th of July. One major thing I will miss upon arriving back in Columbia is falling asleep to the sounds of the Coqui frogs and other nightlife. While providing difficulty sleeping the first night here, eventually they became a welcomed chorus. Every time I spoke to my parents on the phone, they would comment about how loud they were, even when I was inside! One thing I won’t miss so much…the bugs that come out after it rains! Last night, I starred in my very own horror movie with hundreds of flying insects swarming the apartment with more than a handful making their way inside. After tiring of swatting myself repeatedly, I retreated to the bedroom where none had managed to get in. All in all, this trip has been filled with excitement, learning, and the establishment of new friendships with Deborah and Ellee. I couldn’t have asked for a better opportunity to learn more about field research, anoles, and Puerto Rico!

Leal in the New York Times, again!

We shouldn't be surprised by this anymore, but Manuel Leal is back in the New York Times. This article discusses the talk that Manuel gave at the Animal Behavior Society meeting in Alaska last month. I won't spoil the article for you, but here is a very brief teaser: Manuel and his former graduate student (Brian "Ace" Powell) have been trying to figure out how anoles are able to return home after being artificially displaced. Read the story to learn the MANY different ways they try to solve the mystery!

Job well done, El Jefe.
Have a cafecito on me while out in the forests of the Dominican Republic.

I SAW A FEMALE LAY AN EGG and other tales from baby season.

Today, I saw one of the coolest things I’ve ever seen during my 5 summers in the field studying Anolis lizards. I watched a female anole lay an egg!!!!

I happened to come across this female while searching for lizards in one of the plots we are using for our study of A. gundlachi females. Through my binoculars, all I noticed at first was that she was an A. stratulus, and not who I was looking for. As I was about to pass over her, she stood over a small divot in the ground and BAM—laid an egg! I was so surprised I just sat there—I’ve never seen this before!

Unfortunately, I didn’t have my camera with me, but of course I had my handy iPhone. When I came to my senses, I scrambled to the ground as gently as possible, and recorded some frames of this female burying her egg. Watch the (poor quality) video below as she repeatedly butts the ground with her snout, and reaches for moist dirt and debris with her feet. At last, she smoothed the earth over the egg, took a deep breath, and hopped back to a Sierra Palm near by. How cool!

We have loved witnessing baby season here in Puerto Rico! We have managed to see juveniles of three anole species, at different stages of growth. Some are so tiny they must just be days old! Unfortunately, many of our photos don’t do their size justice. So, I’ve included a photo with my finger next to a juvenile A. stratulus to give you an idea.

We've started observing the behavior of A. gundlachi juveniles—stay tuned for more pictures and insights into the comings and goings of tiny lizards!