Category Archives: Notes from the Field

A Doubly Regenerated Tail and Other Morphological Oddities

I’m doing fieldwork with Anolis sagrei in Gainesville, FL, this summer. We now have about 125 lizards  measured and marked, and have come across a number of interesting morphological oddities in these lizards. Most interesting so far is this doubly regenerated tail, i.e. there appear to be two spots at which the tail has regenerated, which means a regenerated tail must have broken and regenerated again.

A doubly regenerated tail in a male Anolis sagrei in Gainesville, FL.

A doubly regenerated tail in a male Anolis sagrei in Gainesville, FL.

Approximately three minutes before we noticed this tail, my field assistant Christian Perez asked me if double regenerations were possible, and I confidently said “no.” As Jonathan Losos puts it in Lizards in an Evolutionary Tree, “when a tail regenerates, the new portion of is made of a rod of cartilage and thus lacks the intravertebral breakage planes that enable an unregenerated tail to autotomize.” So how did this double regeneration happen? Anyone seen this before?

The next oddity is this male with a mysteriously shortened upper jaw:

A shortened upper jaw in a male Anolis sagrei in Gainesville, FL.

A shortened upper jaw in a male Anolis sagrei in Gainesville, FL.

Third, we have a partially discoloured dewlap:

 

A discoloured dewlap in Gainesville, FL

A discoloured dewlap in Gainesville, FL

And finally, here’s an addition to our collection (1, 2) of multiply tailed lizards:

A double tail in an Anolis sagrei in Gainesville, FL.

A double tail in an Anolis sagrei in Gainesville, FL.

 

When You Can Not Get The Results You Expected, Use What You Can Get!

An adult Anolis sagrei male specimen from Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

An adult Anolis sagrei male specimen from Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

Field research does not always go the way we plan. My research partners and I were reminded of that in 2004, when we tried to use a mark-and-recapture method to determine the population sizes of brown anoles (Anolis sagrei) in a small betelnut palm (Areca catecha L) plantation in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan. We ended up with too low recapture rates for our estimates. Still all was not lost! Of the lizards we did recapture, we were able to calculate monthly growth rates and monthly growth percentages. The results indicated that at least some individuals experienced active growth throughout the year. Our results also supported the findings of Schoener and Schoener (1978) and Cox et al. (2009) that smaller individuals of both sexes grew faster than larger conspecifics of the same gender, and that males grew faster than females. We also determined that growth rates of both sexes decreased during the peak reproductive period, suggesting that available energy is directed primarily to reproduction and the associated to behavior, and that energy is only directed towards growth once the requirements for reproduction are met.

The experience from this study convinced me again that it is important to collect as much data as possible when conducting field studies – it is hard to predict where it may come in handy at a later stage.

Crown-giant habitat overlap

Spring is the season for spotting crown-giant anoles in Miami!

I was hosting (recently graduated Lacertid-ophile, although closet anologist) Dr. Robert Heathcote for a few days this week, and after his failed attempt at catching a Cuban knight anole (A. equestris) a fortnight previous, I had promised to deliver him another! Now, I imagine many AA readers may chuckle at someone foolish enough to promise a crown-giant observation (myself included). Much to my relief luck was on our side and we managed to spot not one, but TWO species practically on top of each other!

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A Cuban knight anole (A. equestris) and Jamaican giant anole (A. garmani) perched within 1-2m of each other in Miami FL – April 2nd 2014, JStroud

Cuban knight anoles (A. equestris) and Jamaican giant anoles (A. garmani) are both non-native introduced species to south Florida.

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A. equestris (left) and A. garmani (right) – habitat overlap in Miami FL, JStroud

Anoles have it tough in south Florida!

A common concept in ecology is that predators have a strong influence on the behaviour of prey species. Anolis lizards have been used as a classic model system to investigate the effect of predator presence on the behavioural response of prey species. On small experimental islands in the Bahamas the manipulated introduction of curly-tailed lizards (Leiocephalus carinatus), a large terrestrial anole-predator, has resulted in brown anoles (Anolis sagrei) shifting higher up in the vegetation, presumably in an understandable effort to avoid being eaten (1, 2, 3). However, predator-prey interactions such as these which may shape community structure are often difficult to observe.

Here in Miami FL we have a rich and diverse, although largely non-native, lizard community. There are two species of “crown-giant” anoles, the Cuban knight anole (A. equestris) and the Jamaican giant anole (A. garmani), that could be potential predators of smaller anoles in the canopy of trees and upper half of tree trunks (although see Giery et al. 2013 for an empirical analysis that suggests this may not be the case). Additionally, there are several large, terrestrial lizards present which may be filling a similar role to curly-tails in the Bahamas.

Potential lizard predators in south Florida:

– *Red-headed agama (Agama agama)
– *Cuban knight anole (Anolis equestris)
– Jamaican giant anole (Anolis garmani)
– *Brown basilisk (Basiliscus vittatus)
– Spiny tailed iguana (Ctenosaura similis)
– Curly-tail lizard (Leiocephalus carinatus)
– Giant day gecko (Phelsuma grandis)
– Black and white tegu (Tupinambis merianae)

*Present at Fairchild Tropical Botanical Gardens

Earlier this afternoon, while taking a break from my office at Fairchild Tropical Botanical Gardens (a hot spot for any anologist visiting Miami; 1, 2, 3, 4) in a typical graduate student effort to put off work that I should be doing instead, fellow lab member Evan Rehm and I noticed some scuffling in a nearby bush. At around 2.5m, and admittedly on relatively precarious branches by this stage, sat an adult female African red-headed agama (A. agama) around 30cm from an adamantly motionless adult male Cuban brown anole (A. sagrei)! As we moved towards the bush the agama was quick to ungraciously thump itself to the floor, while the brown anole remained still. On closer inspection, it soon became apparent why both lizards were so high.

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Adult male Cuban brown anole (A. sagrei) found ~2.5m high in Miami FL, supposedly following a predation attempt from an African red-headed agama (A. agama) – JStroud

The significance of tail loss/damage in a population is still debated. The classical view argues that high proportions of tail damage indicates high predation pressure, therefore prey populations are under high predation stress (1). Alternatively, high proportions of tail damage could indicate low predator efficiency, which would suggest prey populations are experiencing low predation stress (1, 2). But the debate doesn’t stop there! Having already lost a tail, a lizard may experience either a resulting increase or decrease in predation depending on the predator species and its associated foraging tactic (1).

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The extent of tail damage is clearer in this photo. The lizard had autotomised the lower half of it’s tail however a secondary half-completed break is also evident – JStroud

African red-headed agamas (A. agama) are similar morphologically to curly-tailed lizards (L. carinatus), although are taxonomically distinct (Agamidae and Leiocephalidae, respectively). Predation of anoles by agamas in Miami has not previously been officially recorded, and the impact of these large predators remains unclear. Unlike in the Bahamas, there are multiple predators in the same geographic vicinity that anoles need to be aware of. For example, at Fairchild, brown anoles (A. sagrei) could be eaten from below by agamas, eaten at intermediate levels by basilisks and eaten from above by knight anoles!

South Florida is a tough place to be an anole!

agama

Adult male African red-headed agama (A. agama) at Fairchild Tropical Botanical Gardens, Miami FL. The population of agamas is localised to the botanical gardens; the source remains unclear but is likely an introduction from the pet trade – JStroud

Turks and Caicos Anole: Anolis scriptus

Much of my research has been conducted on the herpetofauna of the Turks and Caicos Islands (TCI). Known to a chunk of the lay public in North America as a sweet honeymoon spot, the Turks and Caicos boast a wonderful assemblage of terrestrial reptiles, like these IUCN critically endangered TCI iguanas (Cyclura carinata):

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Of course, we on AA prefer the smaller saurians, so I will draw your attention to the TCI anole (A. scriptus scriptus), a member of the Southern Bahamas Anole complex (A. scriptus).

Anolis s. scriptus, Big Ambergris Cay, TCI

Anolis s. scriptus, Big Ambergris Cay, TCI

Also known as the Silver Cay Anole, A. scriptus can be found across the southern Bahamas banks, including the Inaguas, Samana, Plana Cays, Mayaguana, and the Turks and Caicos Islands. I have previously posted about this understudied species (1,2), but spent a good bit of time observing them on my last research trip. They occur throughout the TCI archipelago, from the dense tropical dry forest of North Caicos, to the pine savannas of Middle Caicos and xeric outposts like the Ambergris Cays. They can also be found on nearly every vegetated rock cay.

 

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Male, Big Ambergris Cay

 

The males have an attractive yellow wash on the underside, with an orange-yellow dewlap that is really striking in the bright sun. The males display from elevated perches, but are wary when approached by nosy researchers.

 

The females are more cryptic, both in coloration and in behavior. They often have a light stripe down the back, or occasionally darker crossbars perpendicular to the light stripe.DSC_0977

On Big Ambergris Cay, on the southeastern edge of the Caicos Bank, the anoles especially favor an irrigated area near a decorative plant nursery. They are voracious, taking down large prey like this cicada (Ollanata caicosensis) on the right. Hopefully this voraciousness extends to interspecific interactions, as the “Festive” anole (A. sagrei) has now firmly invaded at least one island on the Caicos Bank (1; more on this in a future post).

Phylogenetically, Anolis scriptus is nested firmly within the radiation of Puerto Rican Anoles (most recently). Most closely related to a trunk-ground clade containing A. cristatellus, A. desechensis, and A. ernestwilliamsi, the TCI Anole exhibits a curious distribution, although they really do resemble A. cristatellus. Much of the terrestrial herpetofauna of the TCI is likely derived from Hispaniola (See TOC on this post), so what did A. scriptus do to get to the TCI? Our recent research on the A. cristatellus clade suggests that A. scriptus most likely dispersed from Puerto Rico around the start of the Pliocene. This could have been accomplished completely over-water, as currents and hurricanes push flotsam in a northwesterly direction from Puerto Rico. Alternatively, the species could have island-hopped on the formerly emergent Silver, Mouchoir, and Navidad banks, now a famous calving ground for the Humpback Whale.

Although I have not visited, the Crooked-Acklins Bank is a curious intersection of Bahamian and southern Bahamian herpetofauna, where the range of the southern A. scriptus (nearby Plana Cays) meets the range of the northern A. sagrei (Crooked Island). Furthermore, the bank is the northern limit of the Southern Bahamas Boa (Chilabothrus chrysogaster), which is replaced just a few kilometers northwest on the Great Bahama Bank by C. strigilatus. Finally, the handsome endemic A. brunneus (1,2,3) occurs there.

 

 

 

Wet Prairie Anolis carolinensis in Two Parcels in Broward County, Florida: Historical Populations?

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Hi Anole Folks,

So life transported me to South Florida to beat Cancer, and looks like I have made good progress, thank you in advance. :-)

As a general naturalist, I get out A LOT, each day- up to three hikes in different habitats.

In my area on the border of Broward and Palm Beach Counties, there are several restored Pine-Lands, some from about 1984- most  cordoned off in a way for even longer due to central farm use, cattle grazing, or logging with left over islands near the wetter areas.

I spent a lot of time in the late 70’s in Coral Gables, Florida-  with a two year stint at the U. of M.  At that time, Anolis carolinensis, while not common, could be found on buildings on Ponce de Leon Blvd. and also areas of Bird Road, LeJeune and others behind the U of M arboretum.  I also would find both A. porcatus and A. chlorocyanus at these locations.  Anolis sagrei was always in great numbers no matter what.

Returning NOW, in 2014- with extensive field searching, failed to find Anolis carolinensis. The typical haunts I’d expect–along homes, in bushes, on trees, and in scrub–failed to yield a single animal.  I put in a lot of effort.  I found A. porcatus, A. equestris, what I think is A. cristatellus, and every morph you can think of of A. sagrei.  I also found Curly Tails living sympatrically with A. sagrei in several pockets.  This I found pretty neat and worthy of some work.

Recently, while hiking a Wet Prairie, along a Cypress Marsh near a domed swamp area, I started to see a very thin green lizard perched atop grass stalks–and very often cattail stalks in the center of the wetland, over standing water.  I could not confirm the species–they were far into the swamp and their flushing distance was ASTOUNDING.   They would see me and DROP clear to the grass below.  One time I saw an individual turn brown in seconds, and disappear, not into tree branches, but into the grass on the ground! I watched this behavior 8-9 times before I knew–I had to hike into the swamp.  So I did.

IMGP0391Eventually I was able to see males and females, of what now I was sure was A. carolinensis hunting and using the grass/cattail stalks for feeding and display.  In the attached image, you will see one on cattail, and this is a typical daily encounter.  I could see five or more in a hike, on the tops of grass stalks near the seed heads.  While bushes and peripheral trees were there, they were not using this substrate. I really was seeing a marshland native Green Anole group.   And to my eyes, this group was rather “gracile” in form.  And they worked the stalks in what seemed to be a new fashion.  I even imagine–since I have not done any morphometrics yet–that their hind legs look longer, tibia/fibula and femur, and toes.  They also have  a posture for most of their time on the stalks that is not something I was used to seeing–legs held way back and tight to the body, as if to reduce their profile.  A thin Green Anole, that can hide on a grass blade :-).   The images here represent two separate anoles from two separate days.

Did the pressures of habitat loss, A. sagrei competition, and A. equestris predatory pressure, isolate this group and/or move them to this grassland habitat over water?  Could this be a recently adapted “ecomorph” which we so timely have read about?

I will be vouchering a male and female for work at the MCZ for others that might be interested.  But in the interim, my favorite interest, watching behavior, will continue.

I know all the BUTS about this- as in- are they even remnants of historical Broward animals at all?  Did they come in with the replanted slash pine and pond cypress?  I’m hoping one day by genetic work, and or even some new Xray work, we might be able to answer some of this.  And of course, in their normal historical lives, they almost certainly used this type of habitat in part.  But what about now?

That there are vigorous groups in these Wet Prairies of Broward attests to the tenacity of the species, and that it is surviving here.  And that  puts a smile on my face!!

If anyone would like additional information for research, and or visit the sites with me, please feel free to contact me at naturalist@gmail.com; I’ll be here for at least a few more months.

Would love any ideas, thoughts regarding this as well.  More photos to come as well.

Enjoy the images.

Sincerely,

Kenneth E. Barnett

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Brown Anoles in Tree Islands

A recent trip to the Everglades with Palm botanist Sara Edelman was meant to provide a welcome break from studying for qualifying exams, and give her the opportunity to further educate me on all things palm (which was previously limited to determining which lizards in Miami appear to live on them).

After spending the morning locating individuals of her study species, the native and state-threatened Paurotis palm (Acoelorrhaphe wrightii), we had received very little wildlife luck (which was the true reason for me volunteering to ‘help’). From past visits, I had found brown anoles (Anolis sagrei) at every car park along the Everglades National Park road down to Flamingo, likely hitch-hiking unwittingly on visitors cars, but to my knowledge they had yet to disperse convincingly out from these. On our second to last survey of the day, to this tree island off the main road just south of Mahogany Hammock, while searching for native green anoles (Anolis carolinensis) which I had yet to see, I heard some rustling in the bushes – lo and behold, sitting there as bold as day signalling straight at me was a male brown anole!

Everglades tree island characterised by Paurotis palm (Acoelorrhaphe wrightii), Saw palmetto (Serenoa repens), Buttonwood (Conocarpus sp.) and Pine (Pinus sp.), and inset brown anole (Anolis sagrei) observed inside

Everglades tree island characterised by Paurotis palm (Acoelorrhaphe wrightii), Saw palmetto (Serenoa repens), Buttonwood (Conocarpus sp.) and Pine (Pinus sp.), with [inset] brown anole (Anolis sagrei) observed inside

Now, observing brown anoles here shouldn’t be a surprise, should it? After all they are already in many surrounding places accessible by car, therefore it was only a matter of time before they spread further afield. However, areas like these in the Everglades may represent one of the last refuges of green anoles from introduced non-native species found everywhere else in south Florida (an idea I mentioned here a few months ago). Tree islands are masses of larger vegetation (unsurprisingly characterised by trees) formed gradually as vegetation clumps in the slow moving Everglades flow. Over time, debris from colonising plants raises the ground level just above surrounding water level, meaning they provide important havens for many wildlife species. During the wet season the dispersal potential for brown anoles would be limited. All of the areas surrounding tree islands are generally inundated, meaning landscape movement through the thin-stemmed sawgrass plains may be easier for more nimble footed green anoles, however somewhat less graceful for browns. This, however, is all hypothetical.

So ruling out human-mediated release or dropping by a clumsy predator, we could assume that this chap arrived there all by himself. This would suggest that brown anoles have no problems in traversing through sawgrass, although temporal factors may be important (i.e. dispersing during the dry season when water levels are low or absent).

The implications for the expansion of this species through the Everglades remain unclear, although their relationship with green anoles leads to a predictable outcome (discussed extensively on AA [1, 2, 3). Just how much effect is a highly fecund, hyper-dense, extremely competitive and resilient insectivore going to have on these small ‘island’ ecosystems?

Trunk-ground Anoles Living in High Rises

This weekend I recently saw an adult male Cuban brown anole (Anolis sagrei) perching higher than I have ever observed – roughly 4m high!

Adult male Cuban brown anole (Anolis sagrei) perching uncharacteristically high

Adult male Cuban brown anole (Anolis sagrei) perching uncharacteristically high

So anole aficionados, what dizzying heights have you observed trunk-ground anoles up to?

*My apologies for the poor quality of the zoomed in sections.

Jamaican Twig Anole Observations

Earlier this year ,while conducting crocodile (C. acutus) research in Jamaica, I observed some interesting behavior with the Jamaican Twig Anole (A. valencienni). The croc research is conducted at dusk and into the night, which leaves ample time to watch the anoles (during the day) that share our campsite. All of the Jamaican anole species are present at our camp in the Hellshire Hills except A. garmani. The camp is located just off the beach in a sea grape and buttonwood dominated coastal forest.

While lying in a hammock, I watched a female A. valencienni descend a branch toward a tree hollow. As she approached the hollow, I noticed several other females near the entrance hole. I know that it is documented that this species is a communal nester, but to see it was a real treat. During a quick survey of the immediate area (about 20 meter radius), I observed this same activity at two other tree cavities simultaneously. Up to five females were perched outside the cavities, while one or two inspected the entrance. At one of the tree cavities, the females were very wary and during several hours of observation, I noticed that the gravid females entered and exited (after deposition) freely.

At two other cavities, there seemed to be a backup. Females would enter or partially enter, then quickly exit the hole. It wasn’t hard to deduce that something else was occupying the cavity. Even more interesting was that the females at these cavities were not wary, actually completely aloof to my presence. I was curious as to what was preventing their access, so I peered and blew air into one of the holes. As I did this, the females at the entrance which were looking at my face only inches away shifted their attention into the hole. I still couldn’t see anything, so I utilized a flashlight and after doing so, saw that a Croaking Gecko (Aristelligar praesignis) was “blocking” entry and appeared to defend the cavity from intruders. Additionally, I noticed the walls of the cavity encrusted with eggs. Considering the size and shape of eggs, all appeared to be freshly laid or previously hatched Anolis eggs.

I cannot explain the female anoles’ behavior and complete disregard of my presence; even allowing me to touch them (see video).

I had several hypotheses about this behavior; one is that perhaps females worked cooperatively to intimidate the cavity occupier (gecko) at entrance… even enlisting the observer as an ally?

After egg depsition

After egg depsition

Before egg deposition

Before egg deposition

Gecko in cavity (blurry), eye and eyestripe can be seen.

Gecko in cavity (blurry); eye and eyestripe can be seen.

Sitana Fight!

Sitana at Manimutharu, Tamil Nadu (photo by Ambika Kamath)

Sitana at Manimutharu, Tamil Nadu (photo by Ambika Kamath)

Earlier this year, I lamented not having any cameras when I witnessed the most epic fight in 5 months of Sitana fieldwork. As luck would have it, I saw an equally impressive fight on the last day of my sixth month of  Sitana observation, and this time I had a video camera! I was working in Manimutharu, Tamil Nadu, at the Agasthyamalai Community-Based Conservation Centre, home to Sitana with partially-coloured dewlaps.

A map of the Sitana populations I've sampled.

A map of the Sitana populations I’ve sampled.

This male-male interaction lasted over 11 minutes, and ended only because I disturbed the lizards. Neither male was injured at all when I caught them after the fight. I’ve broken the video into two parts, one short and one long. The video begins when I realised I was watching two lizards–one is on the large rock to the right, and the other just below the rock on the left. Apologies for the shaky camera-work.

In between the two videos is over two minutes of the lizards biting each other ceaselessly. This length of fighting is atypical–actual combat between Sitana males is usually over in seconds, though the displays and staring-competitions can persist for much longer.  This second video gives a better feel for the pace of these interactions. The lizards start out near the rocks on the right of the screen.

The Grenadines: Caribbean Herpetofauna Islands Of The Day

The Grenadines. (http://en.wikipedia.org/wiki/File:Grenadines- Archipelago)

The Grenadines. (http://en.wikipedia.org/wiki/File:Grenadines- Archipelago)

Check out the Grenadines, a polyphyletic chain of approximately 600 islands found at the southern end of the Lesser Antilles. The islands north of the Martinique Channel are governed by St. Vincent. The islands south of the Martinique Channel are governed by Grenada. (Grenada, you’ll recall, was invaded by the US in 1983).

Given Martinique Channel’s apparent role as a political boundary, I wondered if it is also an important biogeographical boundary, much like Wallace’s Line in Indonesia. Wallace’s line, which passes through through the Lombok Strait between Bali and Lombok and between Borneo and Sulawesi, denotes a clear faunal break between Asian and Oceanic faunas. The biogeographical explanation is that Wallace’s line follows the transition from continental shelf to deep water channel, which serves as a barrier for migration.

Martinique Channel (line added).

Martinique Channel (line added).

A look at the Caribherp distribution of herpetofauna found on the Grenadines suggests that the Martinique Channel is not actually a biogeographic break. The distribution of most herps found on the Grenadines crosses the channel, suggesting that the channel is not a barrier to migration. And, consistent with this, Google Earth suggests that the channel is not very deep.

Oh, almost forgot: the Anolis species on the Grenadines are A. aeneus, A. richardi, and the invasive A. sagrei.

Anolis aeneus. Photo from http://www.kingsnake.com/westindian/anolisaeneus5.JPG.

Anolis aeneus. Photo from http://www.kingsnake.com/westindian/anolisaeneus5.JPG.

Anolis richardi. (Photo from http://reptile-database.reptarium.cz)

Anolis richardi. (Photo from http://reptile-database.reptarium.cz)

Predation On Anolis Sagrei By A Juvenile Southern Black Racer

snake eating sagreiI’m a big fan of predation events,  and after two and a half months of working with Sitana in a site bizarrely devoid of predators, I had high hopes for Miami. I was not disappointed, and on my second day, had the chance to watch this snake capture and eat a female Anolis sagrei. This happened in the grounds of the Florida International University, Biscayne Bay Campus, where I was collecting some preliminary data on A. sagrei territory overlap. The photo is from relatively early in the lizard consumption process, before the snake (a Southern Black Racer, Coluber constrictor priapus) turned the lizard around and swallowed it head first.

I initially thought the anole was A. distichus, which are abundant in the area where I saw the snake. On seeing that it was in fact A. sagrei, I realised that I might have unwittingly played a role in the lizard’s demise. I had in fact been trying to catch a female A. sagrei in the vicinity myself, and must have chased her right into the grasp of this snake! I like to think of the situation as my having facilitated the snake’s successful capture, and not as being out-lizarded by a baby snake, but I know I’m just deluding myself…

Thanks to Gabe Gartner and James Stroud for identifying the snake.

Another Observation Of Nectivory In Anolis

Following previous threads documenting nectivory in various Anolis (1, 2, 3), here is another account recently observed in south Florida, from Florida International University’s palm botanist Scott Zona in Miami:

This American green anole was methodically going along an inflorescence of one of the palms (Ptychosperma macarthurii) in my back yard licking the nectar droplet from the tip of each pistillode. This palm is an exotic ornamental from New Guinea and northern Australia but is widely cultivated around the world. It is monoecious (male and female flowers on the same inflorescence) but strongly dichogamous (separation in time). The male flowers open first. The lizard was lapping up a droplet of nectar that is excreted by the long, slender pistillode (sterile pistil) in each male flower. I watched him for several minutes (and have lots more photos). The lizard was very methodical about going to every flower, climbing to another branch, and then exhibiting the same feeding behavior. It is unlikely that the lizard would be a pollinator, because of the strong dichogamy; however, female flowers also secrete nectar, so if the same anole were to find another inflorescence in the female phase, it could affect pollination.

American green anole (Anolis carolinensis) feeding on the nectar of a palm inflorescence in south Florida

American green anole (Anolis carolinensis) feeding on the nectar of a palm inflorescence in south Florida

Nectivory in anoles has been well summarised in a previous post, in which Ambika Kamath noted that they had observed a a female licking palm flowers in south Florida but regrettably never got a picture – well it may have been a year and 3 months, but here’s one!

With the wealth of introduced anoles in south Florida, I wonder if this feeding behaviour has been observed in other species but not yet documented – the ecologically similar A. porcatus and A. chlorocyanus seem likely candidates…

If anyone would like more information on this, or has a keen interest in palms, please feel free to email Scott directly.

Weird Urban Perches

There is quite a bit of evidence that anoles like to display from relatively high perches (e.g. references in this paper), a tendency that seems to cross over to their Old World counterparts, the agamids (e.g. Sitana ponticeriana, as outlined here). The hypothesized reason for this choice is that displaying from high perches enables lizards to be maximally visible to conspecifics, ensuring that broadcast displays are heeded by the neighbours. This summer, my field assistant Divyaraj Shah spotted a Calotes versicolor in Kutch, India, displaying from the most exposed perch I’ve ever seen a lizard on. See if you can spot it below:

Spot the displaying Calotes versicolor

Spot the displaying Calotes versicolor

 

Continue reading

Name That Big Costa Rican Anole

 

Rick Stanley photo #2 of a large Costa Rican anole

Award-winning nature photographer, naturalist, and undergraduate Rick Stanley spied this large anole in Costa Rica. Is it A. microtus? A. insignis? Something else?

Photo #1

Here’s what Rick had to say: “I encountered these impressive lizards on the Pacific Slope of the Cordillera Talamanca, on the border of Chirripo National Park, in the summer (wet season). They were between 1500 and 1600m elevation, in secondary forest habitat. Although sightings were about a month apart, all of the animals observed were in the same general area near the cabins.

Photo #3

Images 2/3 are of the same individual. Image 1 was taken nearby at an earlier date, so it could be the same individual as well. Image 4 is of a different, slightly smaller individual seen along with 2/3 (perhaps the female?). The male(?) displayed his dewlap at me- I think it was an aggressive gesture, because the female was out of sight by then. When I first saw him, he had a large clump of moss in his mouth that he proceeded to devour (chances are there was an insect in there as well).

Photo #4

The lizards were over a foot long including the tail, although I didn’t catch them and measure svl. The first time I sighted 1 it was sunning. Later, it changed color and appeared more like the individual in photos 2 and 3. Didn’t move much, as I found him in the same place the next day, hanging head down on some vines.

There is also some damage to the animal’s dewlap that isn’t part of the pattern.”

Anoles on the rocks, so to speak

After a wonderful trip to Puerto Rico for the recent Thermal Ecology meeting mentioned here on Anole Annals and so heavily attended by anolologists, we had the opportunity to visit some of the natural forests that the country had to offer.

Riparian habitat in the forest by the El Verde Field Station, Puerto Rico

Riparian habitat in the forest by the El Verde Field Station, Puerto Rico

Whilst in El Verde National Park, we were regaled with stories of local Anolis advancing to the ground and using riparian habitat despite what their ecomorph classification might suggest. Given the recent AA interest in aquatic anoles (1,2,3), I thought a short note on this may be appreciated. Apologies for the deceivingly melodramatic title; alas it was literal, not figurative.

An adult male A. evermanni perched on a boulder surrounded by fast flowing water

An adult male A. evermanni perched on a boulder surrounded by fast flowing water

Anolis evermanni, a trunk-crown ecomorph, has been known to use boulders along one of the streams for the past two decades or so. With great anticipation, whilst marching through the forest spotting copious numbers of Anolis gundlachi, we were en route to our final destination to find out! Upon reaching the stream, which incidentally offered some beautiful tropical scenery accompanying the break in the canopy, we were not disappointed to find A. evermanni dotted all around the waterway!

I assure you there is an anole there - this wasn't just an excuse for a rest...!

I assure you there is an anole there – this wasn’t just an excuse for a rest…!

An adult male A. evermanni displaying

An adult male A. evermanni displaying

Back in 1990, Jonathon Losos postulated that this shift in microhabitat from trees to boulders forced a change in locomotor strategy. Whilst anoles are able to travel continuously in a forest, by travelling down a tree, along the ground and then up another, the structural heterogeneity presented by these riparian boulders meant that jumping needed to be more commonly adopted. He posited that the difference in thermal strategy of A. evermanni and A. gundlachi, a heliotherm and a thermoconformer respectively, would affect their likelihood of using these boulders along the highly sunny stream. Although A. gundlachi were observed present along the shaded edge, they rarely ventured further out. After some thought on site, this prompted a brief hypothesis by a couple of us; when the sun began to disappear, would the larger A. gundlachi displace the A. evermanni on the boulders?

This may take some imagination, but that blur to the right of the central vine - I assure you that's a boulder-loving A. gundlachi!

This may take some imagination, but that blur to the right of the central vine – I assure you that’s a boulder-loving A. gundlachi!

After a couple of hours of enjoying the forests of El Verde, we returned to the field station. As we were leaving and the sun was beginning to calm, I spotted our first A. gundlachi out on a stream boulder followed shortly after by a handful of A. stratulus. This would seem to offer a cool behavioural research opportunity for someone that enjoys sitting in the sun by a river watching lizards…(can’t be that bad a gig, can it?).

A. stratulus also getting in on the gig

A. stratulus also getting in on the action

(K)night Anoles: Nocturnal Activity Facilitated By Artificial Lights?

An interesting aspect of human activity and urban development is the ability of species to respond to new opportunities that did not previously exist. We have seen previous posts (1, 2) on Anole Annals highlighting nocturnal activity in anoles, which are recognised as a predominantly diurnal group. Here is another short observation that I and Sean Giery (of previous Knight Anole fame) observed a while ago whilst doing some night herping at Fairchild Tropical Botanical Gardens which will be published as a short natural history note in an upcoming edition of Herp Review:

On 18 April 2013 between 22:03-22:15 h, a single adult Cuban knight anole Anolis equestris was observed at Fairchild Tropical Botanical Gardens, Miami FL (25.677°N, 80.276°W, WGS84). This individual was observed consuming Lepidoptera attracted to an artificial light source positioned above a doorway. Nocturnal lizards (Hemidactylus mabouia) were also present around the light source and could represent another potential prey source for nocturnally foraging A. equestris. This is the first documentation of A. equestris using artificial light sources to allow for nocturnal activity.

Cuban knight anole (Anolis equestris) active and foraging at night with the aid of a wall light above a door

Cuban knight anole (Anolis equestris) active and foraging at night with the aid of a wall light above a door

This behavioural plasticity provides not only a fascinating, but also just a really cool new branch of anole research. This could be highlighted particularly well with introduced species which may experience interspecific competition levels along axes which in their native range they may not have been exposed to. Stay tuned!

The Effect Of Hurricane Sandy On Abaco, Bahamas Anole Experiments

Did the lizards on this island survive Hurricane Sandy?

Did the lizards on this island survive Hurricane Sandy?

Long time AA readers will recall that every year, a team of researchers go to the Marsh Harbour, Abaco, Bahamas to study how curly-tailed lizards affect brown anoles and, in turn, how the presence of brown anoles affect the rest of the ecosystem on tiny islands. This research, initiated by Tom Schoener and Dave Spiller in the 1980s, has been long-lasting and has produced many interesting discoveries about anoles, ecology and evolution.

But in the last few years, the research has been bedeviled by hurricanes. In 1998 and then again in 2004, studies on the effects of curly-tails on brown anoles were terminated prematurely by hurricanes. We did learn a lot about how hurricanes affect ecosystems, including lizards, but it wasn’t so helpful with regard to understanding how brown anoles evolve in response to predation pressure. After waiting several years for the islands and lizard populations to recover, we re-initiated the experiment again in 2008. At the same time, we started a second experiment by introducing a single pair of lizards to each of seven islands, creating a replicated experiment on the effects of founder events on evolutionary adaptation.

Both experiments were moving along nicely when—what else?—another hurricane hit, Irene in 2011. As everyone recalls, Irene was a big one, and we feared the worst, but by good fortune, its effects were less than catastrophic because it hit at low tide—minimizing the extent of the storm surge—and from a direction that tended to minimize the storm surge on the particular islands we were studying. The result was that some—though not all—island populations were hit hard, but very few were demolished. In fact, I speculated that studying the effect of a population bottleneck on populations created by founder events might be particularly interesting, because some theories suggest that it takes multiple population crashes to lead to great evolutionary changes.

Hurricane Irene ripping its way through the Bahamas. Abaco is the island to the right of the arrow labelled “Freeport.”

So along comes 2012 and… another direct hit on our islands, this time by the infamous Hurricane Sandy. Although initially quite large, by the time Sandy hit Abaco, its wind speeds were less than Irene, giving  us hope. But, on the other hand, Sandy slowed to a crawl, meaning that it remained over Abaco for a long time, not just at low tide, and also from a more threatening direction than Irene’s. All dangerous portents.

dave on founder island

Photo by Jason Kolbe

Thus, with great trepidation, we returned to Abaco earlier this month, anxious to learn how our island buddies had fared. A trip to Abaco last December—admittedly, not the best anole time, even in the Bahamas—had indicated that a number of the lowest lying islands seemed lizardless. And our visit confirmed that finding. The seven islands in our founder effect study are all small and low-lying, and the lizard populations on five of them were wiped out (one of them had a female last December, but she’s apparently gone). One of the remaining islands contains but three anoles—a male and two females—and it will be interesting to observe the effect of this population bottleneck. That population—like all in this experiment—was founded by two individuals and quickly grew in size. Will it rebound again, and just as quickly? Continue reading

The Evolution Of Caribbean Anole Neuroendocrine Systems

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What’s going on inside their heads? The four anole species of South Bimini, The Bahamas.

Whenever I stand in the forest on South Bimini in the Bahamas, I’m always struck by the similarity of these anoles to those I’ve worked with elsewhere in the Greater Antilles. Yes, that’s the whole idea behind the ecomorph concept, but as many have pointed out recently, habitat use and morphological convergence are only part of the story. Along with the classic divergence and convergence in body size and shape, the ecomorphs also show intriguing convergence in sexual size dimorphism and social behavior. It’s this latter aspect of the Caribbean anoles that interests me. How has this convergence in behavior, though it’s not perfect, happened? Have the proximate mechanisms that are responsible for anole behavior evolved in the same way on the various islands in the various ecomorphs? From a larger perspective we are asking, how do neuroendocrine systems evolve? That’s what my students and I are trying to figure out, and that’s why we’re in the Bahamas right now.

A few years back, Matt Lovern and I started a project examining circulating steroid hormone levels in four anole assemblages (The Bahamas, Puerto Rico, Dominican Republic, and Jamaica). Based on a plethora of work in a variety of vertebrate species and their testosterone-behavior relationships, we predicted that we would find consistent intra-island differences among ecomorphs in testosterone (and corticosterone), with the ever-charismatic trunk-ground anoles showing the highest levels. Boy, were we in for a surprise. We did find species differences, and we even found consistent ecomorph differences, but not like we expected. Unlike the mainland green anole (Anolis carolinensis) and the introduced brown anole (Anolis sagrei) on the mainland (yes, the apparent difference in testosterone levels  between mainland and Caribbean brown anoles is probably a separate, interesting story!), trunk-ground anoles in the Caribbean have very low baseline testosterone levels. Twig anoles, on the other hand, are super-juiced with testosterone. I won’t give the whole story away, as we are working on getting it published, but the take-home message is that hormones are only part of the story, and testosterone likely plays very different roles in the behavior of the various species and ecomorphs. While this may not sound surprising to some, in some ways it is, because typically people only focus on circulating hormone levels to explain behavior, and testosterone levels tend to be pretty good predictors at a large scale. Although many proclaim that it’s not the hormones but the receptors, nobody has examined hormone receptor distributions in target tissues across a large number of closely related species. Again, that’s what we’re trying to do here in the Bahamas (and elsewhere).

We’ve been spending our time here on Bimini collecting brains for analysis of several potential regulators of social behavior in multiple brain regions known to be important in anole aggression and courtship behavior. My student Allison, who is here with me now, got some funding to spend the rest of the summer back in Minnesota sectioning and staining brains from the four ecomorphs here on Bimini. We’ve also been conducting “GnRH challenges” on these species to determine whether the baseline levels of testosterone that we’ve measured are as high as they can go. That is, when we physiologically stimulate the hypothalamus-pituitary-gonad axis to produce more testosterone, is it capable of doing so, and are there differences among species in that response? I’ll be spending the rest of my summer running those samples to find out. This will complement the social challenges that Matt Lovern and I conducted in the Dominican Republic last year on Anolis cybotes and Anolis coelestinus, examining whether social challenges result in increased testosterone. Stay tuned to see what we find!

The Anole Bunch-Munch Frenzy

_MG_4001 copyAfter an early afternoon rain in western Cordillera Central of the Dominican Republic, a swarm of “flying ants” emerged from a nest on ground, most of them gathering at top of this antenna pole, attracting the attention of the neighboring community of anoles. Approximately a “platoon” of 2 dozen of A. chlorocyanus started climbing up the 7-8 meter tall pole, a few A. cybotes stayed low, and at least one A. distichus joined the feast. The lizards came from two small wooden buildings and used the wire (seen near top, at right side) and roof-to-nearest bushes jumps to access the pole. Many more came and went. Certainly, there were several males, and dewlap displays were made once in a while, but there was no time (or no real need?) for a fight this time. Some male chlorocyanus live very close to each other in those buildings (along with several females), and show notorious scars over their faces.

Editor’s Note: Here’s another video that Miguel mentioned in a comment (below):