Author: Jonathan Losos Page 8 of 133
Professor of Biology and Director of the Living Earth Collaborative at Washington University in Saint Louis. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.
Bob Trivers published his memoirs, Wild Life, six years ago. We discussed it in these pages and pointed to a favorable book review that appeared in Current Biology, a review with which I agree completely, not surpisingly, since I wrote it.
I commend the book to you, but if you want the short story, check out Trivers’ two-page summary of his life from age 13 to 29 just published in Evolutionary Psychology. The abstract is a good indication of what the short paper holds: “This is a brief history of my intellectual life from age 13 to 29 years—and beyond. It encompasses mathematics, US history, and evolutionary biology, especially social theory based on natural selection.”
This site has all kinds of useful information! Here’s the site’s story (“about us”):
Our Story
Esri created the Caribbean GeoPortal Program to support an open mapping community across the Caribbean. As a global company, Esri’s distributors and employees have been working across the countries and territories in the Caribbean for many years.
The Caribbean GeoPortal is a comprehensive cloud-based platform that is focused on advancing three main goals for the region:
- increasing the capacity of organizations in the region through GIS training and education
- improving collaboration and information sharing among organizations in the region
- providing organizations in the region with the necessary GIS capabilities to support their work
From the pages of the Gainesville Sun , referring to a recent paper in Oecologia.
Danielle Ivanov
The Gainesville Sun
From April to September of 2017, Jesse Borden was climbing trees and counting lizards around Alachua County.
Sometimes, he could be found in branches on the University of Florida campus or in people’s backyards. Other times, his distinctive red helmet popped in and out of leaves in nearby forests.
The 34-year-old UF student is in his fourth year pursuing a doctoral degree in interdisciplinary ecology, and much of his work has focused on Gainesville’s native green anole lizards and their responses to two threats: development and invasive brown anoles.
He found that in the presence of brown anoles, the green natives moved about 17 times higher in trees, or about 8.3 meters in median perch height, to coexist. But the shift did not allow the lizards to overcome their habitat loss from human development.
These findings were recently published on Oct. 7 in the journal Oecologia.
“The extent to which [green anoles] were shifting was pretty fascinating,” Borden said. “That appears to allow them to coexist with the threat of an invasive species, the brown anole that is competing with it, but it doesn’t make them immune to other effects like urban development. And so it seemed like urbanization was the strongest driver of their decline across the landscape.”
Brown anoles were first introduced to the mainland southeastern U.S. in the early 1900s and were well established by the 1940s, according to the study. In Alachua County, they have been established for decades and appear to thrive in urban environments, Borden said. It is not known exactly how they came to the area, but it could have been via cargo and boats.
To study the green anoles’ response to both development and brown anoles at the same time, he and other helpers surveyed 61 trees and the ground around them for lizards twice each, once per day and once after dark. They then statistically analyzed the data for metrics like abundance, perch height and urbanization.
“It was a lot of fun,” Borden said. “Many thanks to so many kind people who let us use their backyard trees.”
The student said his findings raised many questions and topics for future research, such as how much time the green anoles spend higher in the trees. He is currently working on a project looking at evidence for change in body shape across the urban to natural gradient in lizard species here and change in their temperature tolerance to cold.
For Gainesville residents who miss seeing the little green lizards, Borden said, there are a few things people can do to help bolster their habitat space in the city. Planting native vegetation of varying heights in yard space can benefit the green anoles. Protecting and preserving forest patches and trees also supports them and lots of other wildlife.
“I just hope people are noticing the green anoles,” Borden said. “I find them so beautiful. They’re super cool. They’re a really fun and special part of the southeast U.S. and Florida.”
Contact Borden online via Twitter at @JesseBBorden or Instagram at @borden_ecology_adventures.
With over 400 species of anoles (Anolis) scattered from Florida to Bolivia, these slender lizards, widely sold in pet stores, have long been model subjects in evolutionary biology—keys to ecomorphology, adaptive radiation, and convergent evolution. Yet there is still much to discover about them.
Jonathan Huie, a doctoral candidate at George Washington University, while an intern at the Smithsonian’s National Museum of Natural History, set out to determine whether the less-studied anoles of mainland Central and South America have evolved the six ecomorphs—forms adapted to microhabitats, from treetops to trunks to undergrowth—recognized in the much-studied species found on Caribbean islands.
Huie examined 347 anoles preserved in four natural history museums; they represented 205 species, 99 of them from the mainland clade. He measured thirteen morphological traits associated with habitats and modes of locomotion, including the lengths of tails, bodies, snouts, heads, hands, feet, and limb bones and the width of the toe and finger pads anoles use to cling to vertical surfaces. After averaging these values for each species and correcting for body size, he plotted their positions in a multidimensional “morphospace.” He tested their resultant assignments to ecomorphs against available field data.
Mainland anoles were previously considered less ecologically diverse than their Caribbean cousins. But Huie’s findings suggest they occupy all of the same microhabitats; the two groups underwent similar radiation—i.e., convergent evolution—over the approximately 30 million years since anoles from the islands recolonized the mainland. He also found evidence of a previously unrecognized ground-dwelling ecomorph in both groups.
Why was this mainland diversity overlooked? Perhaps because it is much easier to study anoles on the islands, which are celebrated evolutionary hotbeds where, with fewer predators, they are more abundant and visible. “Mainland anoles are a lot more secretive and inhabit more complex environments, such as heavy forest,” Huie noted.
Huie suggests the methods he and his coauthors developed could be applied to study “the relationships between form and function” in other morphological features of organisms, whether plant leaves, frog limbs, or the pharyngeal jaws of fish—especially cichlids, the fast-evolving, highly diverse piscine counterparts of anoles. (Biological Journal of the Linnaean Society)
For more commentary on this paper, see a previous AA post.
Javier Lobon Rovira, a graduate student working on geckos, decided to up his game and pay attention to anoles. Here’s what resulted! The lizards were found on 24th of August in the surroundings of Gainesville, Florida, displaying from a tree branch around one meter high. He found a second specimen close by sleeping at night on a small bush close to a water pond.
AUGUST 6TH, 2021
Lizards with sticky toepads have a greater clinging ability. Above, the tree canopy specialist American green anole (Anolis carolinensis). (Credit: Getty Images)
Data from 2,600 lizard species worldwide indicate that those with sticky toepads prevail.
Many lizards are phenomenal climbers. Their sharp, curved claws are ideal for clinging to tree trunks, rocks, and other rough surfaces. However, in the precarious world of tree tops—filled with slippery leaves and unstable branches—three peculiar groups of lizards possess the remarkable evolutionary accessory of sticky pads on their fingers and toes.
Sticky toepads have independently evolved in geckos, skinks, and Anolis lizards—producing tree acrobats specially adapted to life in the forest canopy. Scientists have long considered sticky toepads an “evolutionary key innovation” that allow arboreal lizards to interact with the environment in ways that many padless lizards cannot.
Yet, some lizards without toepads have adopted the canopy lifestyle, an observation that has puzzled scientists for decades. Biologists Aryeh Miller and James Stroud at Washington University in St. Louis set out to find if lizards with toepads had an evolutionary advantage for life in the trees relative to their padless counterparts.
“Lizards with toepads have a greater ecological advantage in the arboreal environment,” says Miller, a graduate student in the evolution, ecology, and population biology program at Washington University in St. Louis and lead author of the study. “Toepads are essentially a biological superpower for lizards to access new resources that lizards without toepads cannot.”
“We found that lizards with sticky feet dominate the arboreal environment. Once adapted to life in the trees, they rarely leave,” says Stroud, a postdoctoral research associate and the senior author of the paper. “Conversely, lizards without sticky toepads frequently transition away from living in trees to living on the ground.”
The study appears in Systematic Biology.
ANATOMICAL EVOLUTION
“Scientists have long wondered about the role that the origin of key innovation plays in subsequent evolutionary diversification. Lizards are an excellent type of organism for such studies due to their exceptional species richness and the incredible extent of anatomical variation and habitat use,” says Jonathan Losos, professor of biology and director of the university’s Living Earth Collaborative.
Using a recently published database of habitat use for nearly every lizard species across the globe, the researchers were able to perform a comprehensive analysis of toepad evolution in the context of lizard habitat use—for the first time, the evolutionary relationships between which lizards live in trees and which do not became clear.
“Miller and Stroud have developed an elegant new approach to understand this diversity and the role that anatomical evolution plays in shaping the great diversity of lizard kind. This work will be a model for researchers working on many types of plants, animals, and microbes,” Losos adds.
TOEPADS LET LIZARDS STICK AROUND
Miller, who led the analysis, is the first to find that species have evolved for specialized life in trees at least 100 times in thousands of lizards. In other words, it is evolutionarily easy for a lizard to become a tree lizard.
What’s difficult is sticking around (pun intended!). Toepads don’t evolve until after lizards get into the trees, not before. And padless lizards will leave trees at a high frequency—much higher than padbearing lizards.
“There are hundreds of lizards living in the trees, but over evolutionary time many of those species end up leaving for life on the ground because, presumably, they interact with these padded lizards that have a greater advantage,” Stroud says.
The next step in this research is to find out exactly what padbearing lizards can do that their padless relatives can’t. Scientists can learn about this by watching the animals in their natural habitat.
“Analyzing evolutionary relationships can tell us a lot, but next we need to go out into nature—to see what parts of the environment the lizards use and why these evolutionary relationships exist,” Miller says.
Turns out that it happens more commonly than you might think! Here’s the latest report from The Bulletin of the Chicago Herpetological Society, a ferruginous pygmy-owl eating a clouded anole in Mexico.
SCIENTIST STUDIES ANOLE LIZARDS TO HELP CONSERVE VULNERABLE SPECIES
National Science Foundation funds UTA biologist’s investigation of islands’ reptile diversity
A biologist at The University of Texas at Arlington is studying the diversity of anole lizard species in the Caribbean islands to gain insight into why some species are common, while others are rare and possibly at risk for extinction.
The National Science Foundation awarded Luke Frishkoff, assistant professor of biology, a $1.1 million grant to investigate the reptile’s ecological niches, the set of conditions in which an organism can survive and reproduce.
Anoles with a broad niche thrive in a range of ecological conditions; those with a narrow niche are specialized to live in environments that meet their precise biological needs. Knowing the lizards’ niche characteristics will help scientists identify which species are in danger of dying out.
“We are in the middle of an extinction crisis right now, and some species are more likely to go extinct in the next 100 years than others,” Frishkoff said. “Among researchers, there is a common assumption that specialization is a predicting factor for extinction. The narrower the niche, the less likely it is that a species could survive.”
Frishkoff will collaborate with Martha Muñoz, a thermal biologist at Yale University, and Luke Mahler, an evolutionary biologist at the University of Toronto, to examine three aspects of the animal’s niche: diet, where they live among vegetation and how they interact with temperature.
The team’s findings will inform researchers’ strategies to conserve vulnerable species. As a community ecologist fascinated by the question of why various types of animals choose to live where they do, Frishkoff has a driving ambition to preserve the world’s biological diversity.
“When we go hiking and observe the plants and animals that are assembled there, I feel a deep sense of mystery,” Frishkoff said. “For me, the deepest motivation is to understand the rules by which life exists in these complex ecosystems.”
Frishkoff said humans can learn a lot from anoles about how to sustain life on earth.
“These lizards are a treasure trove of knowledge about ecology and evolutionary history, and they are a great model for understanding the fundamental properties of life on earth,” Frishkoff said.
The mainland ground anole Anolis tandai from Brazil. (Photo: Ivan Prates)
The mainland ground anole Anolis tandai from Brazil. (Photo: Ivan Prates)
June 02, 2021
By Kristen Mitchell
A George Washington University Columbian College of Arts and Sciences Ph.D. student recently published a paper about the evolution of Central and South American anoles, a group of tropical lizards that have been historically understudied compared to their distant relatives in the Caribbean. The study was a collaboration with researchers from the Smithsonian National Museum of Natural History.
Jonathan Huie, a Ph.D. candidate in the Department of Biological Sciences, got involved in this work as an undergraduate student through a National Science Foundation research internship at the Smithsonian National Museum of Natural History. This research sparked his passion for lizards and ultimately guided him toward a doctoral program studying salamanders at GW.
Mr. Huie is lead author of the new paper, published in The Biological Journal of the Linnean Society on Wednesday. Mr. Huie spoke to GW Today about the impact of this research.
Q: Why has there historically been such a significant gap between what researchers know about Caribbean anoles and what they know about anoles found in Central and South America?
A: Most of the 400-plus species of anoles live in Central and South America, and yet the lion’s share of anole research has focused on Caribbean species. There are likely several reasons why, but ease and accessibility are definitely important factors. In the Caribbean, anoles are quite abundant and easy to find but mainland anoles are more secretive, likely because they have more predators to hide from. It’s difficult to study what you can’t see.
Another reason may be because islands themselves are excellent study systems. They’re small and easier to make sense of compared to mainland systems. There’s also a lot of them, which is ideal for replication and hypothesis testing. Lastly, science is often conducted where it’s easiest or most desirable to establish a field site so it’s probably no coincidence that many well-studied anoles occur near vacation spots.
With that said, there’s been a huge push in recent years to learn more about mainland anoles. Our study wouldn’t have been possible otherwise, but there is still a lot we don’t know about mainland anoles.
Q: What did your research reveal about how anoles in Central and South America have evolved to fill various ecological niches?
A: Anoles originated on the mainland, then they colonized the Caribbean, and eventually re-invaded the mainland. Caribbean anoles are well-known among biologists for repeatedly evolving sets of species with similar ecologies and morphologies on Cuba, Hispaniola, Jamaica and Puerto Rico. For example, some species live on thin perches like twigs and have convergently evolved short limbs and well-developed toe pads. Other species specialize in living in tree-crowns, on tree trunks, grasses and bushes. We found that when anoles diversified on the mainland the second time, they convergently re-evolved all of the same habitat specialists and morphological adaptations found in the Caribbean—but this time in Central and South America. This is fascinating given what we often believe to be true about islands and continents.
Our second main finding was that ground-dwelling anoles are really common on the mainland and have their own set of morphological adaptations. Many Caribbean anoles forage on the ground, but very few live there full-time. Mainland ground anoles, on the other hand, really took off. We hypothesized that ground anoles are common on the mainland—at least among the group that re-invaded the mainland—because most arboreal niches were already occupied by other lizards. It’s unclear why Caribbean ground anoles are not more abundant.
GW Ph.D. student Jonathan Huie (center) poses with his mentors Ivan Prates (left) and Kevin de Queiroz (right) at the Smithsonian’s National Museum of Natural History in 2018. (Photo: Smithsonian)
Q: How do your findings challenge long-held assumptions made about evolution on islands compared to mainland habitats?
A: We found that island and mainland anoles are more similar than previously thought. For a long time, it was believed that islands were hotbeds for extreme morphologies and that continents lacked the necessary conditions. In the context of anoles, island species were considered to be unique—that the relationship between habitat and morphology was fundamentally different on islands versus the mainland. However, we found strong evidence that this is not the case.
That is not to say that everything we once thought to be true is now wrong—there are still many differences between island and mainland anoles. However, our research shifts how we should view island and mainland comparisons. Our paper joins other recent studies in suggesting that the mainland is equally good at cultivating morphological diversity as island environments.
Q: How did you get involved in this research, and how did it shape the kind of research you are doing now as a Ph.D. candidate?
A: I got involved as an undergraduate National Science Foundation Research Experiences for Undergraduates (REU) intern at the Smithsonian’s National Museum of Natural History in 2018, under the co-mentorship of Ivan Prates and Kevin de Queiroz. I was a total fish geek and had never studied anoles, but I signed on to investigate the link between habitat and morphology in a handful of mainland anoles.
I measured their body proportions using the museum’s natural history collection but finished quickly. So, we started adding more and more species, and even after the internship was over, I continued to visit other natural history collections to measure even more lizards. The next thing I knew, I had looked at more than 200 species. Natural history collections like the Smithsonian were absolutely critical for this work and fostering my interests beyond fishes.
As a Ph.D. student, I am currently studying salamander limbs to better understand the type of adaptations needed to make the water-to-land transition. The kinds of questions I am interested in for my dissertation are similar to the ones we approached with the anole project. Without my internship, it’s very unlikely that I would have ended up at GW studying salamanders.
Q: How are you planning to build on this research moving forward?
A: There is still so much left to do. In our recent paper, we only published about half of the data I initially collected. We are excited to dive deeper and look at how body size influences patterns of morphological adaptation.
There’s also the other group of mainland anoles that we didn’t look at. I am interested in knowing more about how these other mainland species fit into the puzzle. Did they adapt in a similar manner as the group of mainland anoles we looked at? Or are they doing something different? We would like to know how often evolution repeats itself to produce similar outcomes.