Hello all! I’m working on Puerto Rican anole field identification. Here’s a specimen I photographed on the ruins atop El Yunque on March 4, 2019. I think it’s a juvenile A. evermanni, but I’m curious what you guys think!
Scanning electron microscopy (SEM) is a technique that utilizes electron beams that interact with and reflect the surface of a viewed specimen. These reflections allow the evaluation of surface topology and ultrastructure and give high-resolution detail about external structures and cellular arrangements (Goldstein et al. 2017). To create a reflection on specimen surfaces, a thin layer of gold is mechanically applied through a process known as “sputter-coating.” Recently, graduate students at Auburn University had the opportunity to view their own collected biological samples with SEM through an Applied and Environmental Microbiology course taught by Dr. Mark Liles.
As a student in this class, I had the opportunity to view a chosen sample under this process. While I highly debated bringing in an anole fecal sample (which would have been gold-coated and placed on my desk for a lifetime), I decided to view a recently dried, fertile A. sagrei egg collected from the lab of my advisor, Dr. Daniel Warner. The microbial communities on the surface of this egg were most likely highly impacted by the influence of drying (see image descriptions below); this is due to sample preparation required by conventional SEM, whereby water vaporization will distort images if the sample is not completely dry. Part of my research within the Warner lab involves investigating the microbial communities on the external surface of eggshells; thus, this class has provided an excellent opportunity to explore how varying environmental factors can influence eggshell microbiomes. The photos taken and attached were observed on 03 April 2019.
In Image 1 at 42X magnification, you can see the influence of drying from the large indentions on the egg as well as horizontal cracking within the surface itself. However, under closer inspection fungal and bacterial structures begin to appear. In Image 2 at 397X magnification, you can view a filamentous structure that we predict to be fungi. One of the limitations of SEM is that while structures can be easily viewed, they may not always be as easily identifiable. At 1,500X and 1,5700X, we can see a magnified image of a fungal root (Image 3) and potential bacterial cells above the spiral filamentous structure (Image 4).
Image 2. SEM image of A. sagrei egg at 397X magnification.
Image 3. SEM image of A. sagrei egg at 1,500X magnification.
Image 4. SEM image of A. sagrei egg at 1,5700X magnification.
The images above highlight the interesting use of SEM for reptilian eggs, especially those small enough to be entirely encompassed under a microscope (< 1.5 mm long). SEM observations can also be used to elucidate differences in eggshell structures, thickness, and porosity (Heulin et al. 2002). Additionally, SEM use within the classroom setting has allowed students to gain applicable skills and techniques, as well as their own photographs (Beane 2004).
References:
Beane, Rachel J. 2004. “Using the Scanning Electron Microscope for Discovery Based Learning in Undergraduate Courses.” Journal of Geoscience Education 52 (3): 250–53. https://doi.org/10.5408/1089-9995-52.3.250.
Goldstein, Joseph I., Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy. 2017. Scanning Electron Microscopy and X-Ray Microanalysis. Springer.
Heulin, Benoit, Samuele Ghielmi, Nusa Vogrin, Yann Surget‐Groba, and Claude Pierre Guillaume. 2002. “Variation in Eggshell Characteristics and in Intrauterine Egg Retention between Two Oviparous Clades of the Lizard Lacerta Vivipara: Insight into the Oviparity–Viviparity Continuum in Squamates.” Journal of Morphology 252 (3): 255–62. https://doi.org/10.1002/jmor.1103.
Read more about Elaine Powers’ books, including her most recent post, “Stop and Meet the Anole Lizards,” on her author’s webpage.
Anolis chloris soaks up the sun while displaying.
If you’ve ever spent some time in the Caribbean, you might have noticed that humans are not the only organisms soaking up the sun. Anoles – diminutive little tree lizards – spend much of their day shuttling in and out of shade. But, according to a new study in Evolution led by Dr. Martha Muñoz at Virginia Tech and Jhan Salazar at Universidad Icesi, this behavioral “thermoregulation” isn’t just affecting their body temperature. Surprisingly, it’s also slowing their evolution.
The idea that evolution can be slow on islands is actually somewhat strange. Ever since Darwin’s journey to the Galapagos, islands have been recognized as hotspots of rapid evolution, resulting in many ecologically diverse species. The reason why evolution often goes into overdrive on islands has to do with the ecological opportunity presented by simplified environments. When organisms wash up on remote islands, they find themselves freed of their usual competitors and predators, which frees them to rapidly diversify to fill new niches. This phenomenon of faster evolution is often referred to as the “island effect.”
Yet, the researchers discovered that physiological evolution in Anolis lizards is actually much slower on islands than on the mainland. What is causing evolution to stall? According to Dr. Muñoz, the same ecological opportunity that frees island organisms from predators also facilitates behavioral thermoregulation. “Whereas mainland lizards spend most of their time hiding from predators, island lizards move around more, and are able to spend much of their day precisely shuttling between sun and shade,” she says. If it gets too hot, island lizards simply go find a shady spot. If it gets too cold, they can dash onto a sunny perch. By thermoregulating, island lizards are not just buffering themselves from thermal variation. They are effectively shielding themselves from natural selection. If lizards aren’t exposed to extreme temperatures, then selection on physiology is weakened. The result? Slower rates of physiological evolution. Effectively, island lizards use behavioral thermoregulation like SPF against natural selection!
Jhan Salazar notes that, “Our results show that faster evolution on islands is not a general rule.” This slower physiological evolution on islands stands in stark contrast to morphology, which has been shown to evolve faster in island anoles. When it comes to morphology and physiology on islands, it seems we are looking at different sides of the same coin. The same ecological release from predators and competition that allowed for the truly impressive amount of morphological diversification that has appeared quickly among island anoles, seems to additionally allow for more behavioral thermoregulation which slows physiological evolution.
“We are discovering that organisms are the architects of their own selective environments,” says Muñoz, “meaning that behavior and evolution are locked together in a delicate dance. This pas de deux tells us something important about how diversity arises in nature.”
Jhan Salazar holds an anole from Colombia.
A. cristatellus copulating on metal
A. evermanni dewlaping on wall
A. cristatellus riding the dolphin
A. cristatellus dewlaping on metal
Fig. 1. Anoles perched on various manmade surfaces
Lizards in the city are everywhere! Often you see them on buildings, statues, benches and other objects (Fig 1). These manmade structures are very different from natural substrates and thus might affect their locomotor ability and escape responses. This observation led me to develop questions around how lizards respond to incoming threats when using these artificial structures. I am very grateful that I got to “get my feet wet” tackling some of these questions during my master’s degree as a member of the Kolbe Lab in the University of Rhode Island.
In our recent paper, we contrasted the escape response of Anolis cristatellus in forests versus cities, and within the latter, between lizards perched on natural versus manmade surfaces. We selected this question because we believed that the heterogeneity of habitat structure in the city might influence the decision-making of flight responses. When a predator approaches, an animal should flee when the costs of staying outweigh the energetic costs of fleeing. Consequently, we hypothesized that the cost of flight varies when the animal is perched on smooth surfaces. However, we expected that city lizards should have reduced flight responses largely influenced by habituation to humans.
The bad habits of habituation
One of the major hurdles involved designing our project to separate the component of behavioral adjustments to humans versus structural habitat differences when contrasting escape responses. The literature often has used the concept of habituation as a discussion point when contrasting flight responses of habitats that differ in human activity. Only a few studies have attempted to quantify how human activity might influence escape responses. We explored this concept by sampling lizards perched on trees at edges of a forest trail or sidewalk that were frequently visited by pedestrians and cyclers. Lizards perched closest to the trail or sidewalk should be more exposed to human activity and respond with reduced flight initiation distance. We found that forest lizards perched at the edge of the trail had shorter flight initiation distances (Fig. 2). Lizards perched 4m away from the trail had longer flight responses. In contrast, city lizards sampled at trees along a sidewalk showed no difference in flight response with increasing distance from the sidewalk. With this, we were able to show how habituation influenced escape responses, possibly driven by the degree lizards were able to see human activity. At 4m from the forest trail, we had very limited visibility of the trail. In contrast, in the sidewalk at 8m away from the sidewalk, we could see the sidewalk, the road and the sidewalk at the other side of the road. However, more work specifically directed to tackle the concept of habituation is needed to understand its role in facilitating the successful colonization of urban habitats.
Fig. 2. Log flight initiation distance of lizards sampled with increasing distance away from a trail in the forest or a sidewalk in the city.
The wall
City lizards were abundantly using cement and metal structures. For this reason, we compared escape responses of forest lizards on trees to city lizards on cement, metal and trees. Most of the cement structures were large buildings, whereas metal often included fence posts and light fixtures. Both metal and cement are smoother than bark and greatly reduce stability during locomotion. When lizards run vertically on smooth surfaces, they are more likely to slip and fall. We hypothesized that such locomotor constraints should increase the cost of flight and thus lizards on manmade surfaces should have longer flight initiation distances. We found that forest lizards had the longest flight initiation distance (Fig 3). Surprisingly, we found that there was no difference in flight response between city lizards perched on trees and those on metal posts. Metal perches were often cylindrical and lizards could circle around the perch, breaking away from the line of sight. In contrast, cement walls were often long and required lizards to either slowly move up and out of reach or sprint longer distances to circle towards the next connecting wall. The ability to quickly hide with a short burst of movement decreased the cost of flight on metal posts.
Fig. 3. Flight initiation distance of forest anoles perch on trees and urban anoles perched on trees, metal posts and cement walls.
Escape in the city
We found that even though sprinting performance is lower on artificial perches, lizards often perch on these surfaces. It’s likely that behavioral modulation plays a role in increasing their success in evaluating predation risk when using these perches. If I were to continue this study, I would track individual lizards to contrast their response when perching on the various natural and man-made surfaces. Additionally, multiple tests on marked individuals would allow for a more appropriate test of habituation across these populations.
The adhesive structures of geckos have been the subject of extensive inquiry across a variety of disciplines ever since Autumn et al. (2002) discovered that van der Waals intermolecular forces are the main driver of gecko adhesion. Geckos adhere to surfaces using expanded subdigital scales (scansors/lamellae) that are covered in thousands of beta-keratin fibrils (setae) that branch into hundreds or thousands of triangular-shaped tips (spatulae) that are about 200 nanometers in width (see slideshow for images). Spatulae make intimate contact with a surface resulting in van der Waals intermolecular forces. Gecko adhesive toe pads are multifunctional; they are a reversible dry adhesive, they can adhere to a variety of surfaces, they can adhere underwater in some conditions, they have self-cleaning and self-drying capabilities, and they can adhere in a vacuum (see Autumn et al. 2014 for a recent review of gecko adhesion). A number of gecko-inspired synthetic adhesives have been generated over the years, but have not yet managed to replicate the multifunctionality observed in the natural system (Niewiarowski et al. 2016). There are a number of potential explanations for this, but one could be that most gecko-inspired synthetic adhesives are simplified single fibers that do not fully replicate the multiply branched structure of gecko setae. Anoles, however, have independently evolved adhesive toe pads with fundamentally simpler microstructures compared to their gecko counterparts; anole setae are single fibers with a single, larger spatulate tip and more closely resemble the gecko-inspired synthetic adhesives that are currently capable of being generated (see slideshow for images). Therefore, anoles may be an excellent model fibrillar system to better understand the observed functional discrepancy between synthetic and natural fibrillar adhesives.
In an invited paper recently accepted for publication in Integrative and Comparative Biology, my co-authors and I (see full citation below) briefly reviewed the relevant literature concerning the anole adhesive system, discussed how investigation of this convergently evolved system could impact our general understanding of fibrillar adhesion, and suggested a number of hypotheses and areas of future inquiry that could be tackled in future work.
Anole adhesive toe pads have often been suggested as evolutionary key innovations (Losos 2011), yet they have not been nearly as well studied as gecko adhesive toe pads. Nevertheless, general morphometrics, clinging ability on smooth substrates, and correlations between adhesive toe pad size, clinging ability, and habitat use have been reported for anoles (Losos 2011). Studies, however, reporting Anolis clinging ability on ecologically-relevant surfaces, detailed morphometric data of anoline setae, and the multifunctional properties of anoline adhesive toe pads are limited or nonexistent. Anoles may be excellent models for fibrillar adhesion for four main reasons: (1) anole setae are closer in dimensions and morphology to the currently producible gecko-inspired synthetic adhesives, (2) anole setae are not multiply branched which may reduce the complexity of modeling and/or explaining adhesion especially under non-ideal circumstances, (3) anole setae also more closely resemble the theoretical models previously used to explain gecko adhesion, and (4) the extensive evolutionary and ecological data on anoles may assist in answering persisting questions regarding the adhesion ecology and evolution of adhesive pad-bearing lizards.
Although the gecko adhesive system has been particularly well-studied over the past two decades, many fundamentals of biological fibrillar adhesion still need to be worked out or are otherwise unknown. We believe that parallel investigation of the anoline fibrillar adhesive system may assist in filling these gaps in our knowledge, and thus we encourage an interdisciplinary, communal effort to investigate the adhesive ecology, evolution, morphology, performance, and behavior of anoles.
Full citation
Garner, A.M., M.C. Wilson, A.P. Russell, A. Dhinojwala, and P.H. Niewiarowski. Going Out on a Limb: How Investigation of the Anoline Adhesive System can Enhance our Understanding of Fibrillar Adhesion. Integrative and Comparative Biology. In press. Link to article.
References
Autumn K, Niewiarowski PH, Puthoff JB. 2014. Gecko Adhesion as a Model System for Integrative Biology, Interdisciplinary Science, and Bioinspired Engineering. Annual Review of Ecology, Evolution and Systematics 45(1):445-470.
Autumn K, Sitti M, Liang YA, Peattie AM, Hansen WR, Sponberg S, Kenny TW, Fearing R, Israelachvili JN, Full RJ. 2002. Evidence for van der Waals adhesion in gecko setae. Proceedings of the National Academy of Sciences, USA 99(19):12252-12256.
Losos JB. 2011. Lizards in an evolutionary tree: ecology and adaptive radiation of anoles. University of California Press.
Niewiarowski PH, Stark AY, Dhinojwala A. 2016. Sticking to the story: outstanding challenges in gecko-inspired adhesives. Journal of Experimental Biology 219(7):912-919.
Up until the mid-1980s, there had never been a recorded sighting of the Maynard’s Anole (Anolis maynardi) on Cayman Brac island despite it being less than 10km from its native territory, Little Cayman.
However, since the species was first discovered on Cayman Brac in 1987 – in what is thought to have been a human-assisted colonisation – its population has spread right across the 39km² island.
For this study, recent graduate Vaughn Bodden and Lecturer in Conservation Biology Dr Robert Puschendorf conducted a detailed analysis of the invasive species.
They wanted to assess whether individuals at the forefront of the invasion have developed distinct biological traits that are advantageous for dispersal, and compared their findings to animals in the area of first introduction and the native population on Little Cayman.
They discovered the Cayman Brac population has diverged morphologically from the native population, and within the invasive range there was trend of increasing forelimb length from the core to range edge areas. This ran contrary to the expected findings that longer hindlimbs would be the trait selected as a dispersal-related phenotype.
They also showed that the introduced population had lower levels of parasite prevalence, and that both males and females were of significantly higher body condition than the native population.
Writing in the Journal of Zoology, they say the results are a perfect example of how a species can colonise a new territory, and the biological adaptations it can make in order to do so.
Vaughn, who graduated with a First from the BSc (Hons) Conservation Biologyprogramme in 2018, said:
“There has been a history of lizard studies indicating that longer hindlimbs are an important factor affecting movement ability, so to not find longer hind limbed animals on the range edge was a surprise. For parasites, we found a clear decreasing trend in prevalence within the invasive population from the area of first introduction to the range edge, indicating that the parasites lag behind the host during periods of range expansion.
“We think our findings add to the growing body of literature that demonstrates the complex dynamics of species’ invasions. The results highlight that the animals on the range edge of an invasion are likely to be experiencing different ecological selection pressures that can result in changes in behaviour, morphology, and health for the animals.”
Dr Puschendorf has spent several years researching the consequences of emerging infectious diseases and climate change on biodiversity, with a particular focus on Central America. He added:
“Biological invasions are an important conservation threat across the world. However, every invasion needs to be carefully investigated to identify impacts to native eco-systems and identify potential mitigation strategies.
“In this instance there is likely to be limited overlap with, and therefore a limited threat to, the endemic anole population – the Cayman Brac Anole (Anolis luteosignifer) – because one inhabit the crowns of trees while the other is found closer to the ground. This in some ways highlights the challenges biodiversity managers face when managing species invasions with limited resources, and emphasises the need for greater collaboration among scientific and policy communities.”
Inbar Maayan tells all about her ongoing work in the cover story of this month’s issue of Flicker, the bimonthly bulletin of the Cayman Islands Department of Environment’s Terrestrial Resources Unit. Check it out, and also read about Caymanian fossils and the massive effort to eradicate invasive green iguanas (half a million and counting!).
Green Anole
Appearance: Anolis carolinensis is a beautiful green lizard, growing to approximately 8 inches in length, including the tail. Males are larger than females and have proportionally larger heads. The dewlap is usually pink (but can also be grayish or greenish), and is much larger in males than in females. Green anoles can undergo dramatic color changes, from bright green to dull olive, brown, and even yellowish. For this reason, many people in Florida call them “chameleons,” although the green anole’s color-changing ability is modest compared to the true chameleons (Chamaeleonidae) of Africa and Madagascar.
Ecology and Habitat: The green anole’s body shape is that of a trunk-crown ecomorph. But with no other native anoles sharing its range in the southeastern U.S., it historically ranged from the ground to the treetops, making it more of a habitat generalist than Greater Antillean trunk-crown anoles. Today, it shares much of its range with the brown or festive anole (A. sagrei), a Cuban species introduced to Florida around the turn of the 20th century. Many observers believe that the brown anole is driving a decline in green anole populations. This may be true in some places, but another possibility is that green anoles spend more time in the trees where they coexist with brown anoles. In fact, in areas where these two species coexist, the green anole is usually seen on higher perches than the brown anole (which, as a trunk-ground ecomorph, is typically found within a couple of meters of the ground).
Green anoles are active foragers, moving around trees and shrubs in search of prey. They primarily eat insects and spiders, but will also prey on small vertebrates, consume fruit, and even drink nectar from flowers.
Geographic Range and Biogeography: Anolis carolinensis lives throughout the southeastern U.S., from Florida to North Carolina on the Atlantic coast, and west along the Gulf coast through Texas, all the way to the Rio Grande.
Its closest relative is the Cuban trunk-crown species, A. porcatus. Genetic analyses show that the green anole is probably descended from A. porcatus populations from western Cuba, which probably dispersed over water to Florida. The extent of genetic differences between A. porcatus and A. carolinensis suggest that these two species have evolved independently for at least 6 million years, which means that humans played no role in the original colonization of North America by the ancestors of today’s A. carolinensis.
Finally, the green anole itself has become established in many places outside its native range, probably because of its popularity in the pet trade. Today, you can find A. carolinensis in the Pacific (Hawaii, Guam, Palau, and other islands), the Caribbean (Grand Bahama, Anguilla, Grand Cayman), and in southern Japan.
Research Highlights
Anolis carolinensis is a very well-studied species. In a charming 1876 paper titled “The Florida Chameleon,” the Rev. S. Lockwood recounts detailed observations of his pet green anole, a lizard he called “Nolie,” and concludes that the green anole “…is everything that is commendable; clean, inoffensive, pretty, and wonderfully entertaining; provoking harmless mirth, and stirring up in the thinker the profoundest depths of his philosophy.”
Since the late 19th century, biologists have learned a great deal about the green anole, and it has become a model organism for studying many aspects of reptile biology, including the regulation of behavior and reproduction by hormones, social behavior and communication, and the biology of regeneration (because, like most anoles, the green anole can lose and re-grow its tail). In 2011, because of its key role in many subdisciplines of biology, the green anole became the first reptile species to have its entire genome sequenced.
A few recent studies are particularly fascinating. Recall that green anoles coexist with invasive brown anoles (A. sagrei) in parts of their range (see Ecology and Habitat above). In a 2014 study, Yoel Stuart, Todd Campbell, and colleagues studied these two species in Florida by introducing brown anoles to a subset of small, manmade islands that were already inhabited by green anoles. They found that not only did green anoles move to higher perches on the islands they shared with brown anoles, but that over a period of 15 years, the green anoles evolved larger toe pads and more toe pad lamellae (both traits associated with better climbing ability). This may be the best evidence yet that competition between anole species can drive their evolutionary diversification.
Green anoles were in the news again after a 2017 study by Shane Campbell-Staton and colleagues. Studying green anoles in Texas, they measured the lizards’ cold tolerance before and after the winter of 2013-2014, when Texas experienced an abnormally cold “polar vortex” event. Their results show that the extreme cold caused natural selection on the anoles, with southerly populations exhibiting greater cold tolerance after the 2014 polar vortex, on average, than before. Campbell-Staton also used cutting-edge genetic techniques to identify some of the genes that may be involved in cold tolerance.
Species account author: Neil Losin
For more information:
Anolis carolinensis at Animal Diversity Web
Anolis carolinensis at Encyclopedia of Life
Crested Anole
Appearance: The crested anole, Anolis cristatellus, is a medium sized lizard (50-75mm SVL in adult males) with a stocky body and relatively long limbs. It is light brown in color and both males and females have varying patterns of dark brown on their backs including mottled coloration, hourglass patterns, and longitudinal stripes. As the common name implies, many individuals have a large tail crest (different from the nuchal crest that can be erected in many species), although there is substantial regional variation in this trait and many individuals have no tail fan at all. Dewlap color is typically two-toned with a yellow center and a thick orange outer edge, although some populations have a more monotone yellow-orange dewlap. Females are smaller than males (30-45mm SVL adults) and have relatively small dewlaps. Post-anal scales are not easily visible in this species, sometimes making it difficult to distinguish females from juvenile males.
Within the native range, this species may be confused with Anolis gundlachi and Anolis cooki. Anolis gundlachi can be distinguished from A. cristatellus by the yellow-tipped chin, blue eye, and solid yellow dewlap, but is otherwise similar in size and appearance. Anolis cooki is more difficult to distinguish from A. cristatellus, but the two only co-occur in the dry forests of southern Puerto Rico. In their non-native range in Florida, this species may be confused with Anolis sagrei, which is slightly smaller in size and has a dewlap that is red-orange in the center with a thin band of yellow on the edge.
Ecology and Habitat: The crested anole is a trunk-ground ecomorph. It typically perches relatively low to the ground (around 2m high or lower) on broad diameter trees. It is often observed in foraging position on tree trunks with head downward as it sits and waits for insect prey to pass by on the ground. It typically eats insects and spiders, but is also known to consume fruits and to prey on small vertebrates, including anoles of their own and other species. This species is rarely seen on the ground except for when moving between perches or catching prey. Like other trunk-ground ecomorphs, A. cristatellus, has relatively long limbs and a stocky build ideal for quickly navigating both arboreal and ground habitat. Anolis cristatellus is commonly found at lower elevations in warm forest habitats and is often restricted to edge or open, disturbed forest habitat at cooler, high elevations. This species is the most common and abundant anole in urban areas in Puerto Rico.
Geographic Range and Biogeography: Anolis cristatellus is endemic to the Puerto Rican bank (Puerto Rico and the Virgin Islands). Its closest relative is A. desechensis, which is found only on the island of Desecheo off the west coast of Puerto Rico. It is also closely related to A. scriptus (found in the Turks and Caicos), A. cooki (found in dry forests in the southwest of Puerto Rico), and A. monensis (found on the island of Mona off the coast of Puerto Rico). Genetic analyses indicate that the ancestor to A. cristatellus (and 12 other Puerto Rican species, which make up the “cristatellus” group) likely colonized Puerto Rico from Hispaniola at least 40 MYA. More recently, A. cristatellus has established in several places outside of its native range, facilitated largely by sale of tropical plants. In particular, it is established in Miami (Florida), Dominica, Costa Rica, Mexico (Yucatan), Trinidad, Saint Martin, and the Dominican Republic.
Research Highlights:
Anolis cristatellus is a great study species for answering so many different questions! As the most wide-ranging Puerto Rican species, it is perfect for comparative studies. Researchers have found no end to the questions they can answer by examining variation within A. cristatellus in different environments and between A. cristatellus and other Puerto Rican species.
For example, with populations in cold, wet, montane habitats to hot, dry, coastal habitats and everything in between, A. cristatellus is perfect for comparing how populations vary in physiological tolerances. Because of this, A. cristatellus has played a major role in our understanding of thermal preferences and tolerances. This follows largely from Ray Huey, Paul Hertz, and colleagues’ foundational work in the 1970’s-80’s, which compared thermal preferences and tolerances of A. cristatellus and established that A. cristatellus is a thermoconformer in some habitats and a thermoregulator in others. Recent work on thermal tolerance in A. cristatellus has made great strides in our understanding of thermal physiology of anoles. For example, researchers have found that thermal tolerance in A. cristatellus can rapidly shift in new environments. Manuel Leal and Alex Gunderson found that in Miami A. cristatellus tolerate much cooler temperatures than populations in Puerto Rico, and Shane Campbell-Staton and Kristin Winchell found that urban populations in Puerto Rico tolerate much hotter temperatures than nearby forest populations.
In addition, because they are widespread in disturbed environments in their native and non-native range, they provide a great opportunity to study rapid contemporary adaptation in response to environmental change. For example, Luisa Otero has found that reproductive patterns vary with habitat disturbance over small geographical scales and Joshua Hall found that embryo survival and development is impacted by urban thermal spikes. Urban environments in particular have received substantial attention, with researchers in Miami examining invasion dynamics and artificial night light use, and researchers in Puerto Rico finding shifts in habitat use, morphology, and performance in urban environments.
Species account author: Kristin Winchell
For more information:
Reptile Database: http://reptile-database.reptarium.cz/species?genus=Anolis&species=cristatellus
Animal Diversity Web: https://animaldiversity.org/accounts/Anolis_cristatellus/
Invasive Species Compendium: https://www.cabi.org/isc/datasheet/93810