Almost anyone who cares about anoles in the US is aware of the hypothesis that the arrival of brown anoles (Anolis sagrei) into Florida has driven declines in the abundance of native green anoles (A. carolinensis). Though there is certainly evidence that this hypothesis may be valid to some extent, we’ve previously wondered if the decline is as severe as folks seem to think it is. Have green anoles instead simply shifted to higher perches where we don’t see them as often? An informal mark-recapture effort conducted in Gainesville FL suggests that green anoles may in fact be quite abundant, and based on the evolutionary history of green and brown anoles across their ranges, we do in fact expect green anoles to shift upwards where they co-occur with brown anoles.
Green anoles, increasingly elusive in Florida
We now have yet another piece of evidence that green anoles may be thriving at the tops of trees , just out of sight. Because of Hurricane Irma, which wreaked havoc across Florida last week, many of those tree canopies have fallen to the ground. And Miami herpetologist Steven Whitfield reported yesterday seeing “more green anoles in the past two days than I have in the two months before that.” This observation was confirmed by other local biologists as well, in comments on Whitfield’s initial Facebook post that said “Green anoles are all over the place. Seems they were around up in the canopy, but now the canopy is on the ground so they’re easy to see.”
iNaturalist has built an artificial intelligence that can identify species from photographs. You can read more about this work here. It’s a powerful tool to help connect people to the natural world and help grassroots conservation efforts overcome species identification issues.
This artificial intelligence now works on about 20,000 species globally for which we have sufficient data to on which to train the model. We need your help to make it work better on the genus Anolis!
There are 416 known species of anole, but only 197 species have been observed on iNaturalist. And only about 25 species have enough observations (~20) to include in the artificial intelligence.
We need your help to:
Upload your photos of anoles, particularly those which are data deficient in iNaturalist
identify photos of anoles posted by others so that they can be used to train the artificial intelligence
To get started, navigate to the genus Anolis page on iNaturalist by clicking on ‘Species’ in the menu and searching for the genus Anolis. Once you’re on the genus Anolis page, 1. you can see the current count of how many Anole species of the total have been observed. Click ‘View all’ to see the full histogram. 2. Clicking on the Trends tab will list some of the ‘Wanted’ species that haven’t yet been observed as well as recent additions to the tally. As more Anole observations are uploaded and identified, the stats on this page will update.
Upload your photos of anoles
First Log In or Sign Up to iNaturalist.
Then Click ‘Add’ from the dropdown in the main menu to launch the upload tool.
Drag your anole photos into the upload tool. Each card represents a single observation, you can drag them to combine them. Make sure you add 1. identifications, 2. dates, and 3. locations to each card. Then, 4. submit your observations. Identify photos of anoles posted by others
Assuming you’re logged in to your account, Click ‘Identify’ under ‘Observations’ in the main menu to launch the identify tool.
From the identify tool, 1. Enter ‘Anoles’ in the ‘Species’ field and 2. optionally add a country or other location into the ‘Place’ field to filter observations of Anoles that need identifications. 3. Click on an observation to view it in more detail. If you can identify it, 4. click ‘Add ID’, choose a species, and 5. Save your identification.
Anolis cybotes, female from Barahona, Dominican Republic
Katharina Wollenberg Valero & Ariel Rodríguez
Thermal adaptation is the evolution of the ability to persist in novel thermal environments. Phenotypic characters that allow such adaptation, as well as the resulting shifts in the geographic distributions of species, are an emerging field of study in the midst of a changing global climate. Yet, the genomic basis of such phenotypic adaptation is less well understood, so recent efforts of evolutionary biologists are now aiming at one emerging question: Which genes determine thermal adaptation, and are these the same across different populations and species? Luckily, Anolis is yet again at the forefront of novel discoveries being made in this field (see Campbell-Staton et al., 2017).
Many studies have independently identified genes that are responding to changes in the thermal environment, be it through change of expression under an acute stress, or through changes in the DNA sequence as evolutionary response. In 2014, we gathered information on such thermal adaptation candidate genes from Drosophila to Homo sapiens from the literature.
From the published evidence, we extracted a set of gene functions that potentially underlie climatic adaptation. We were able to match these with functions that are known from phenotypic thermal adaptation (Wollenberg Valero et al., 2014). Interestingly, the products of these genes (Proteins, RNAs) were found to be functionally related with each other thus forming gene networks within the cellular environment.
The Caribbean Anolis cybotes is widely distributed across Hispaniola, and thrives in hot, xeric environments just as well as in cooler and more humid montane environments. The rift valley of Lago Enriquillo heats up to 40.5 °C (104.9 °F), and a few instances of frost were reported at the highest peak (Pico Duarte at 3,098m elevation) – so population survival across these climatic extremes does not seem to be a trivial endeavor.
Populations of this species show pronounced differences between montane and lowland forms in morphology, physiology, behavior, and perch use (Wollenberg et al., 2013; Muñoz et al., 2014), which led us to expect that at least some of this variation should have a genetic basis. Thus, we set up to test whether Anolis cybotes displays any signatures of genomic adaptation to the diverse kinds of environments it inhabits, and whether any genes showing evidence for selection can also be subsumed under the candidate functions we defined previously.
We sampled tissue of these lizards from several high and low elevations (the specimens being the same as in Wollenberg et al., 2013), and looked for variation according to climatic differences via RAD sequencing and subsequent analysis with LFMM. RAD sequencing generates a reduced representation of the target genome, producing thousands of short sequences representing the distribution of the restriction enzyme’s cutting sites throughout the genome. Owing to this property, it cannot be expected that this type of data will necessarily contain “the total set of adaptation genes”; to this effect, detailed genome sequencing is required and such studies have been done in some model organisms (stickleback fish, beech mice, Drosophila, etc.).
AA reader Jonathan McFarland sent in these disturbing photos with the following remarks:
“I hope you can shed some light on what’s happening to the wild anoles in my Louisiana suburban yard. This week I have found two adolescents with both eyes bleeding or infected. The attached pictures show only one side of the specimens but in each case both eyes appeared as shown. Any info you could provide would be much appreciated.”
Jamaican giant anole (Anolis garmani) – one of the many non-native anoles you may see in Miami, FL.
In 2018 it will be nearly ten years since the last Anolis symposium was held at the Museum of Comparative Zoology at Harvard University. Given the rapid advances and exciting new discoveries in Anolis biology, it’s time to organize the 7th Anolis symposium! So, with this official announcement, please mark the weekend of March 17-18th 2018 in your calendars to come and visit the wonderfully tropical lizard-world of Miami, FL!
The aim of the symposium is to bring together Anolis biologists from diverse backgrounds to share their excitement and discoveries for these marvelous lizards. In this symposium, we hope to foster cross-disciplinary collaborations of people working with anoles and to broaden our general understanding of their biology and natural history. Miami was chosen not only for its spectacular anole diversity, but because of its ready access to anolologists living outside of mainland United States.
Miami, FL, is an ideal place in the USA to host this meeting! Over the past 100 years, eight species of Caribbean anoles have joined one native species in becoming established in south Florida. This meeting will be held on the weekend of March 17-18th 2018, which broadly overlaps with at least one weekend of the Spring Break holiday for most US schools, and does not conflict with other major meetings as far as we’re aware. We hope that this will facilitate good attendance! The symposium will be held at the Fairchild Tropical Botanic Gardens, which is home to a diverse community of exotic lizards, including six (!) species of anoles (read more about them here and on Anole Annals here!).
This post serves as a ‘save the date‘ – stay tuned the Symposium page for more information on conference registration, abstract submission for oral and poster presentations, and article submission for the Anolis Newsletter VII.
Puerto Rican crested anoles (A. cristatellus) in Fairchild Tropical Botanic Gardens
The first plate from the Sanger et al. (2008) Anolis staging series.
Long time readers of this blog will likely remember the many posts I’ve made trumpeting the utility of anoles for integrative analysis of anatomical diversity, studies that gain perspective from disparate biological fields. The community has come a long way since we published the first staging series of anole embryology only nine years ago. To some this may be old news, but I still find this pace exciting and personally motivating. Decades of ecological and evolutionary studies have created a strong foundation upon which to build new insights about the molecular and developmental underpinnings of anatomical diversity. My lab’s questions boil down to trying to shed light on the developmental origins of adaptive anatomical variation. Otherwise stated, where did the requisite phenotypic variation arise from during the adaptive radiation of anoles. The inherently comparative nature of these studies led me to use anoles as a “model clade,” a group of species that provides the capacity to obtain evolutionary insights the way that “model species” have provided pure developmental biologists and geneticists the power to deduce insights in their areas.
One of the highest hurdles to the progression of Anolis as a model system has been long-term access to living embryos. Although comparative biology is a powerful approach for evolutionary studies, one of the hallmark lessons of modern Evo-devo is the need to experimentally validate the candidate molecular changes associated with anatomical evolution. If I hypothesize that Gene X underlies some phenotypic difference between two species, I must 1) show that it is expressed at the time when the difference arises and 2) somehow tweak the expression of Gene X at that time and in that tissue to show that the changes parallel those observed in nature. To do this you must have access to an embryo in culture, unencumbered from its opaque shell.
Over the past several years several people have been working on ways to gain access to lizard embryos. The first report of a culturing method was by Tschopp et al., who used lentivirus to trace cell migration into the genitalia and limbs. I have not personally been able to consistently replicate those conditions, especially for later embryos. Bonnie Kircher and I, however, recently published two relatively “simple” culturing protocols as part of a new book, Avian and Reptilian Developmental Biology. One of the challenges of earlier culturing attempts was bacterial and fungal growth. As a first step to combatting these invaders, we developed a protocol to sterilize the eggs, soaking the eggs in a weak bleach solution (yes, a literal bleach solution). From there we were off and running.
The first method we describe, following from advice from Raul Diaz, has worked on eggs a few days old to those that are nearly half way through their incubation period. Using a fine pair of scissors, we separate the outer opaque lays of the shell from the inner membranes that surround the embryo and yolk. This bag-of-embryo is then transferred to a small culture dish with a nutrient rich media and drugs to further combat bacterial and fungal contamination. This culturing system has worked well for up to ten days, roughly from the time the limbs are developing digits to the time that the limbs have visible scales on them. (Check out the video!) In principle, this method will allow better access to the embryo for viral injection or the application of small molecule inhibitors that disrupt particular signaling pathways.
Be warned, the second method is a little more Frankensteinian. Because the membranes cover the embryo, visualizing development remains difficult. To circumvent this problem, we developed a protocol where we explant a piece of anole tissue, such as the developing
A developing A. sagrei foot explanting onto a chicken embryo
limb, to a chicken embryo. Both anole and chicken seem to fare well at 33 degrees Celsius, below the standard incubation conditions of the chicken and above that of our anoles. Development appears to proceed normally in the explanted tissue, just as it does would in an embryo within its own shell. These experiments still have a relatively low success rate, but when the explant takes, it works well. To better visualize the tissue for imaging we also stained the tissue with a vital fluorescent dye before the transfer, giving the tissue a wonderful Halloween feel.
The work is far from over. These culturing protocols are just the first step and will not work for all applications. More technically challenging steps especially await those that want to manipulate the anole genome or target distinct patterns of gene expression. This is only the start of what’s to come. For more details about these protocols you can download the chapter here.
The knight anole is really getting around these days: Turks & Caicos, Grand Bahama, Grand Cayman and many other islands. Now they’ve made it to Abaco, Bahamas, where one individual was captured and possibly two others seen (see article in IRCF Reptiles and Amphibians). Abaco Scientist has an insightful discussion of introduced reptiles and amphibians on Abaco.
Photo-chronicler of Floridian natural history Karen Cusick has done it again. We’ve been captivated by her backyard photos before, but here’s photo of a female green anole with sand on its snout. Been digging holes to bury her eggs, maybe? And while Karen observed the little lady lizard, it suddenly darted into the bushed and emerged with a meal!
Lizards are active creatures, often running around in new territories to explore and find food. Sometimes they encounter challenges that keep them from running too far. When they wander away from home, how do they get back? It’s a question that’s led researchers to study this topic.
After watching the daily routines of Anolis lizards by using tracking devices placed on their backs, researcher Manuel Leal learned that they return to the same home again and again. This established the next question which was to find out how the lizards knew how to get back. Birds have a similar ability to find their way home. Although the exact method has not been discovered, it’s possible that lizards have similar abilities and functioning as birds in finding their own again.
They Claim Their Homes
Anolis lizards, especially males, claim trees as home territories, fighting to keep any newcomers off their bit of land. They’ve proven that they remember exactly where they stake out their claim, and like all animals, they like structure in their environment, including the location of where they spend their days and nights. Some studies prove that after disorienting the lizards and placing them a far distance from their home, they can still find their way back within 24 hours.
Then They Listen
U.S. Geological Society geologist John Hagstrum proposed that in order to get back home, pigeons use sounds wave; extensive studies on pigeons show that they use low-frequency sound waves to create an acoustic map of where they are. This way, they can identify predators and safe spaces to land. Some have wondered whether Anolis lizards might have similar capabilities that are advantageous for homing.
If you want to learn a little more on the topic of how Anolis lizards find their way home, you can see a short film done by Days Edge Productions that follows Leal as he conducts his study.
