All posts by Jonathan Losos

About Jonathan Losos

Professor and Curator of Herpetology at the Museum of Comparative Zoology at Harvard University. 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.

Evolutionary Predictability: Can We Predict the Color of One Lizard Species by Looking at Repeated Patterns of Geographic Variation on Other Islands?

Thanks to the work of Roger Thorpe and colleagues, Lesser Antillean anoles are renowned as an example of adaptive geographic variation. On many islands in the Lesser Antilles, populations in wet areas, where vegetation is lush, are green in color, whereas those in more xeric areas tend to be a drab gray, often with markings on their back. This pattern is repeated on many different islands, the convergent geographic variation thus making a strong case for the adaptive basis of anole coloration.

See Pavitra Muralidhar’s previous post for more information on geographic variation in Lesser Antillean anoles.

In a new paper in PLoS One, Thorpe takes this work a step further, asking whether we can use the parallel patterns seen across Lesser Antillean islands to predict the coloration of an anole species on another island. The focal species is Anolis bonairensis, which occupies the extraordinarily dry island of Bonaire (see our previous posts on this species).

The prediction: A. bonairensis should be grayer and drabber than populations of anoles that occur at the driest sites on Lesser Antillean answers.

The answer: yes! Just as predicted, Anolis bonairensis is one drab lizard. Score one for evolutionary predictability!

thorpe

Anolis bonairensis is represented by the red circles. The x-axis goes from aridity on the left to the most mesic on the right. As you can see, A. bonairensis‘s color and patterning is well-predicted by variation in other species.

New Mainland Green Anole Recognized

Anolis biporcatus, one of the prettiest of anoles. Photo by Thomas Marent

Anolis biporcatus is, if I’m not mistaken, the largest mainland beta/Norops anoles, attaining a length of ca. 100 mm snout-vent. In addition, it has an enormous geographic distribution, ranging from southern Mexico to Ecuador. In a new paper in Salamandra, a team of New Mexican and Ecuadorian biologists headed by Janet Armstead have sliced off part of the species, raising the Ecuadorian/Colombian A. biporcatus parvauritus to species status. They make this decision based on a detailed analysis of morphology and molecular data. Their data also find deep genetic subdivisions within A. biporcatus in Costa Rica, suggesting that there may be more cryptic species awaiting recognition.

A key difference between the species is the color of the distal scales on the dewlap of males, white in biporcatus, black in parvauritus.

biporc male

Note, too, that like many mainland anoles, the males and females have very different dewlaps.

biporc females

Here’s the distribution of the two species:

map

More On Blue-Eyed Anoles

Anolis etheridgei. Photo by Rick Stanley.

Anolis etheridgei. Photo by Rick Stanley.

Three-and-a-half years ago, I wrote a post on the phylogenetic distribution of blue eyes in anoles. They pop up all over anole phylogeny and in species with diverse habitats and geography. The post attracted 32 comments.

At the time, I asked if anyone had a photo of the blue-eyed Anolis etheridgei. Photographer par excellence Rick Stanley quick obliged, but I never got around to posting his photo, so here it is.

But the bigger question is: what about those blue eyes? Why hasn’t anyone studied the phenomenon? If you’ve got a good photo of a blue-eyed anole, send it here!

Green Anole Displays to Wren

Photo by Barb Karl

Photo by Barb Karl

Everyone who has studied anoles in the field has had the experience of an anole displaying towards him- or herself. Do anoles actually display to real predators in the field? We’ve even had one AA post reporting a test of that. But there are few observations of such displays. So we were delighted to receive the following note from Barb Karl of Leland, North Carolina:

I was mowing my lawn and was startled by a green lizard that jumped to a nearby tree. I researched what type of lizard it was since we just moved to North Carolina a short while ago and wanted to see what it was.  I found that it was an anole.  I felt bad that I had startled him, so put some live mealworms on the fence as a peace offering.  I checked a little bit later and he was back on the fence, hopefully eating the mealworms.  Then a short distance away a wren appeared in the bird feeder tray.  I watched the anole, he was still on the fence and started going up and down (almost like he was doing pushups and his throat pouch would go in and out). It was like he was trying to make himself bigger so the bird would not want to mess with him.  It was an awesome sight!

I spotted a second Anole on a tree a distance away from the first one.  Can’t wait till they visit again.  Next time I will try and catch a video if it happens again.

The Extended Evolutionary Thesis and Anoles: the Evolution of Phenotypic Plasticity

Tobias Uller at Lund University is studying phenotypic plasticity in anoles to address the evolutionary significance of such plasticity. He’s interviewed at David Sloan Wilson’s siteThis View of Life. The whole interview is interesting, but here’s the snippet on anoles:

One of my projects, with evolutionary developmental biologist Nathalie Feiner, will test if plasticity shaped diversification of Anolis lizards. These lizards are textbook examples of an adaptive radiation because, across the Caribbean, a single species gave rise to multiple species, each locally adapted to a different habitat. We are particularly interested in limb morphology since it is a defining feature of adaptive differences between species; lizards that run around on broad surfaces, such as tree trunks, have longer limbs than those who cling onto twigs, for example.

Anolis equestris. Image used with permission of Tobias Uller.

We already know from work by Jonathan Losos and others that limb growth is plastic in Anolis. What we do not know is if evolutionary diversification of limbs took place through modification of those particular components of bones that respond to mechanical stress during growth – as would be predicted if plasticity ‘took the lead’ in evolution – or if adaptive divergence between species is unrelated to plastic responses within species. To test the concordance between plasticity and evolutionary diversity we rear a lot of lizards from several species on different surfaces and combine this with detailed measures of skeletons of very many species across the entire Anolis group.

We should also remember that plastic responses in some cases can carry over to the next generation. In experiments on water fleas, which have the advantage that they can reproduce clonally so we can rear genetically identical individuals in the lab, we will test the hypothesis that such maternal effects (or non-genetic inheritance) facilitate adaptation to new environments. In some ways, this works just like plasticity within a generation. That is, successful accommodation of environmental stressors enables populations to persist and gives natural selection something useful to work with, thereby providing directionality to evolution.

But here there is another twist that has to do with the evolution of inheritance. As populations adapt, selective removal of costs and negative side-effects should make maternal effects behave like signals, sent from mothers to tell offspring about the environment they are likely to encounter. This process, therefore, describes the evolution of a type of inheritance system.

We cannot study the conversion of an environmentally induced stress response to a detection-based inheritance system in the lab. But we can compare water flea populations that have been exposed to the same stressor, such as metals or toxins, for a different number of generations in the wild. Ultimately, this should give insights into how inheritance systems evolve and how they come to transmit information.

Experimental Study Demonstrates Anolis humilis Avoids Aposematic Prey

humilis paper

Aposematic warning patterns are supposed to have evolved to warn potential predators to stay away. But do they work? An experimental study at the La Selva Biological Station in Costa tested that hypothesis on common ground anoles, Anolis humilis. Baruch et al., writing in the Journal of Herpetology, presented the anoles with clay models painted in an aposematic or cryptic color. The models were dangled in front of the lizards and wiggled around, simulating a flying insect. Sure enough, the lizards went after the cryptic models nearly half the time, but almost completely ignored the orange and black ones. Aposematic patterns work!

The Horned “Rhino Lizard” of Sri Lanka

ceratophora

Here at AA, we love lizards with horns on the tip of their snouts. The horned anole, Anolis proboscis, is of course our favorite, but there are others. For example, Sri Lanka is home to the little known Ceratophora stoddardiAnima Mundi, an online magazine produced by an Italian husband-and-wife team, just had a nice seven page spread on this species, which it dubs the “rhino lizard,” replete with beautiful photos and a bit of natural history information. Like the horned anole, the rhino lizard can move its horn! I wonder what would happen if they ever met. Who knows? But if you want to learn more about the rhino lizard, check out our previous post on the species.

Cover Photos Needed for New Book on Honduran Reptiles

Two years ago, the Museum of Comparative Zoology published Randy McCranie’s book on the anoles of Honduras. Now, the MCZ is soon to publish Randy’s latest work, a massive compilation on the lizards, crocs and turtles of Honduras, to be titled, appropriately enough, The Lizards, Crocodiles, and Turtles of Honduras: Systematics, Distribution, and Conservation. 

How would you like your photograph to grace the front or back of this forthcoming volume? We’re looking for beautiful photos of Honduran lizards, crocs or turtles. The front cover photo must be vertical in aspect, the back cover horizontal. We can’t offer to pay you, but we’d be happy to provide you with a copy of the volume when it appears.

Please send photos to anoleannals@gmail.com

Thanks!

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Back cover of Anoles of Honduras

Rat and Goat Removal Gives Anolis nubilus Another Shot

Colin Donihue and Anthony Herrel just completed their trip to Redonda to study Anolis nubilus and no doubt they’ll report back to us shortly. Meanwhile, a tip of the hat to AA commenter Nathan Manwaring for pointing out this article posted on Fauna and Flora International’s website:

Redonda harbours a number of endemic species that occur nowhere else in the world, including the Redonda tree lizard (Anolis nubilus), Shown here. In 2015 all of the surviving reptile species were evaluated by IUCN as Critically Endangered. Credit: Jenny Daltry/FFI.

Captivating Caribbean island to be given a new lease of life

Posted on: 21.07.16 (Last edited) 5 August 2016

Starving goats and predatory rats to be removed from Redonda to restore this Caribbean island to its former glory.

The Government of Antigua and Barbuda has announced plans to remove goats and invasive rats from its most rugged and remote offshore island to allow endangered wildlife and their habitats to recover.

Redonda is home to a unique array of plants and animals, including rare lizards found nowhere else in the world. The uninhabited and seldom visited island is also formally recognised as an Important Bird Area, supporting globally-significant numbers of seabirds.

However, the island’s plant and animal populations are disappearing fast thanks in large part to its population of over 5,000 aggressive black rats (an invasive alien species) which prey heavily on the island’s wildlife. Together with the herd of long-horned goats that was brought to Redonda by humans more than a century ago, these mammals have transformed this once-forested island into a moonscape. So few plants survive that even the goats now face starvation.

Redonda from the air. The island, once forested, now looks like a lunar landscape. Credit: Jenny Daltry/FFI.

Redonda from the air. The island, once forested, now looks like a lunar landscape. Credit: Jenny Daltry/FFI.

Redonda is over 50 hectares in area and rises dramatically from the Caribbean Sea, 56 km south-west of Antigua. Goat skeletons litter the island, along with the relics of stone buildings from a guano mining community that lived here until the First World War. With few trees left to stabilise the ground, soil and rocks are crumbling into the sea, threatening nearshore coral reef in the waters below.

“We cannot stand by and watch as a part of our country, part of our history, disappears. We cannot be responsible for decimating animal populations on a regional scale,” says local conservationist Natalya Lawrence of the Environmental Awareness Group (EAG).

The Redonda Restoration Programme has been formed by the Antigua & Barbuda Government and EAG in collaboration with partners from the UK (Fauna & Flora International, British Mountaineering Council), USA (Island Conservation) and New Zealand (Wildlife Management International Ltd).

“I am immensely proud that my ministry has been a driving force in the development of this major initiative,” says Honourable Molwyn Joseph, Minister of Health and the Environment. “Restoring Redonda to its full glory will be a great achievement for our country.”

A new home for starving goats

One of the first steps will be to capture and move the remaining goats to Antigua, where they will be cared for by the Department of Agriculture.

The miners also left behind a herd of long herd goats. Together with the rats, these animals have transformed this once-forested island into a moonscape. So few plants survive that even the goats now face starvation. Credit: Jenny Daltry/FFI.

The miners also left behind a herd of long herd goats. Together with the rats, these animals have transformed this once-forested island into a moonscape. So few plants survive that even the goats now face starvation. Credit: Jenny Daltry/FFI.

“The goats are starving to death on Redonda and must be removed for their own sake,” explains Astley Joseph, Deputy Director of the Department of Agriculture. “We believe it is important to rescue this rare breed because it could have useful drought-adapted genes that would benefit other herds on Antigua and elsewhere.”

Rats will then be eradicated using a rodenticide bait that has previously been used to restore more than 20 other Caribbean islands without harming native wildlife. This is scheduled to be completed by mid-2017.

Black rats are omnivorous, and are known to attack native wildlife, such as ground-nesting birds and reptiles. Credit: Jenny Daltry/FFI/OICP.

Black rats are omnivorous, and are known to attack native wildlife, such as ground-nesting birds and reptiles. Credit: Jenny Daltry/FFI/OICP.

“We and other international organisations have offered our support because we recognise that this is a very challenging yet globally important initiative” says Sophia Steele, Eastern Caribbean Project Coordinator at Fauna & Flora International. “Recent studies have identified Redonda as the most important island to restore in the Eastern Caribbean due to its Critically Endangered wildlife and the high probability of lasting success.”

The new programme is funded by the UK Government’s Darwin Initiative, the National Fish and Wildlife Foundation, the Taurus Foundation and private sponsors. Additional technical and in-kind support is being provided by Caribbean Helicopters and Syngenta Crop Protection AG.

Dr Helena Jeffery Brown of the Department of the Environment says, “Antiguans and Barbudans will be proud as Redonda becomes a role model for regional biodiversity conservation. This will be yet another example of how this country is proactive in meeting the national and international commitments it has made to conserve biodiversity.”

Redonda is also an Important Bird Area thanks to its regionally- and globally-significant colonies of seabirds, including these brown boobies. Credit: Jenny Faltry/FFI/OICP.

Redonda is also an Important Bird Area thanks to its regionally- and globally-significant colonies of seabirds, including these brown boobies. Credit: Jenny Faltry/FFI/OICP.

Antigua and Barbuda has a wealth of experience and success under the ongoing Offshore Islands Conservation Programme which has, since 1995, removed rats and other invasive pests from 15 islets closer to Antigua in the North East Marine Management Area. This has saved the Antiguan racer – once the world’s rarest known snake – from extinction, and enabled an incredible recovery of other native animals and plants. Many tens of thousands of residents and tourists now visit and enjoy Antigua’s pest-free islands every year.

“I am most excited to see the progression of recovery on Redonda once the threat of invasive species is removed,” says local biologist Andrea Otto, who will be part of the research team documenting the recovery process. “I want to see which types of vegetation spring up first and which birds return. From what we have seen on the smaller islands we have restored, the transformation will be incredible.”

For more information, read the press release.

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