Author: James T. Stroud

I am most interested in understanding how different species of lizards live together. Specifically, I research the ecological mechanisms that facilitate coexistence and the subsequent evolutionary consequences. I am a post-doc in the Losos Lab at Washington University in St. Louis. Website: www.jamesTstroud.com

Brown Anoles in Tree Islands

By James T. Stroud

On February 10, 2014

In All Posts, Introduced Anoles, Natural History Observations, Notes from the Field

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.), 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

By James T. Stroud

On February 4, 2014

In All Posts, Introduced Anoles, Natural History Observations, Notes from the Field

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

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.

Strange Dewlap Colour and Pattern

By James T. Stroud

On January 28, 2014

In All Posts

Here’s a picture of an Anolis cristatellus I recently found in Miami (FL) with a strangely coloured dewlap (next to a more typical dewlap colour and pattern). I have no extra details other than I found one other individual that was similar close by, although with less grey. I have never seen it on any other cristatellus in the area. So strange I thought I would share!

Left: Atypical dewlap, Right: Typical dewlap

Although I intended to post this just because of my natural curiosity, it also gave me the added bonus of being able to annoy WordPress’s US-English spellcheck with my title!

Another Observation Of Nectivory In Anolis

By James T. Stroud

On September 3, 2013

In All Posts, Natural History Observations, Notes from the Field

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

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.

Anoles on the rocks, so to speak

By James T. Stroud

On August 8, 2013

In Natural History Observations, Notes from the Field

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

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

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…!

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!

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 action

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

By James T. Stroud

On June 29, 2013

In Introduced Anoles, Natural History Observations, Notes from the Field

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

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!

Miami Anole Safari (Part III)

By James T. Stroud

On January 31, 2013

In Introduced Anoles, Notes from the Field

Firstly, let me start by offering my sincere apologies for the standard of photography you are about to view. As you AA readers have become accustomed to Jonathan’s flowing prose, and other members’ excellent use of modern photographic equipment, I must warn you not to expect either here!

As has been mentioned previously, the IBS Conference was a tremendous success, and firstly huge congratulations must be passed on to (a potential anologist in the making?) Ken Feeley for all the hard work and effort. The lack of talks concerning arguably one of the world’s most studied vertebrate biogeographic systems did not detract from the high levels of anole hunting that ensued over the course of the conference!

After a wonderful afternoon visiting Miami’s most bizarre lizard community, the following day provided an opportunity for conversations to be followed up from the previous night’s conference dinner (as some graduate students’ memories may have appeared a little hazy on Saturday morning). Much of the day was spent wandering around FIU’s Biscayne Bay Campus eagerly trying to find the dozen knight anoles that were promised to us the previous night by resident expert, and thoroughly nice guy, Sean Giery.

Sean has spent the past 3 years observing the A. equestris community on this campus, and has assured me that he will bless AA readers with a synopsis of his eagerly awaited dietary analysis paper in the near future. The day started brightly, with two juveniles being found in close proximity to each other; however with just he and I as the only observers, it was tough to include these individuals in the promised dozen.

Juvenile knight anole found on a horizontal branch ~2m high. Photo by JStroud

At the start of lunch, and confronting the midday heat with the enthusiasm of schoolboys on a day trip, we regrouped with some extra eyes and headed back out to continue on our quest. Although A. sagrei, A. carolinensis and A. distichus were abundant, these were still not the target species. A loud thump behind us saw us all swivel in synchrony, like a troop of sunburnt and slightly dehydrated Michael Flatley fanatics, to be confronted by a rather startled green iguana that had just plummeted 10 feet after submissively losing a dispute to a larger male. The campus had previously been awash with a healthy population of green iguanas; however the big freeze of 2009 reduced this significantly so that the only survivors were those small enough to retreat underground.