Anole Annals

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 Lichen Anole and Evidence for Parental Care

By Kimberley Carter

On April 5, 2017

In Notes from the Field

During an excursion with Indigo Expeditions to Estación Biológica Las Guacamayas, Parque Nacional Laguna del Tigre, Guatemala, we observed the unusual behaviour of a female Lichen Anole Anolis beckeri (previously Anolis/Norops pentaprion), a rarely-studied, canopy-dwelling, anole from Central America. In a paper in Mesoamerican Herpetology, we report on observing a female A. beckeri potentially tending and guarding eggs. This is possibly also an example of oviposition site fidelity in an anole.

Seven Anolis beckeri deposited in the base of a Bromeliad. Photo: Kimberley Carter

Seven unknown lizard eggs were first discovered on 9th July 2015. The eggs were deposited in the leaves of a bromeliad plant (Bromelia sp.) roughly 5m above the ground. The lichen anole is typically a canopy-dwelling species but, luckily for us, the bromeliad was in a tree at eye level to one of the research station’s balconies! The bromeliad plant had collected water and one egg in particular, lying partially submerged, was a brown, speckled colour. Another of the eggs appeared indented, a sign of potential imminent hatching. The female A. beckeri deposited an additional egg after our return to the UK, which reflects similar egg laying pattern for Anolis where independent, single eggs are laid every 5–25 days during the breeding season (Losos, 2009).

Over the next few days there were no changes in the eggs’ shapes or colour. It wasn’t until 3 days later, on the 12th of July, that we finally witnessed the owner of these eggs: a female A. beckeri sat above the clutch on one of the fronds of the bromeliad. The anole was seen repeatedly climbing into the bromeliad, seemingly to examine the eggs. She would then lick them and exhale heavily over them (perhaps to increase airflow?), before retreating to the top of the bromeliad. She repeated this sequence of behaviours, retreating to safety up the tree and then re-emerging to check on the eggs numerous times.

Video stills of the female Anolis beckeri tending the eggs. Photos: Kimberley Carter

We recorded these behaviours on video and in photographs from a distance, to avoid disturbing the lizard. The female returned on numerous occasions to examine, lick and ‘aerate’ the eggs or to seemingly guard the eggs over the next few days but on the 14^th of July the female only monitored the eggs from a distance of ca. 30 cm away and did not approach them.

We also witnessed potential predatory behaviour from a Mexican Parrot Snake (Leptophis mexicanus), On the 15^th July the snake was seen in the vicinity of the clutch, perhaps attempting to prey on the adult female. See full paper for detail.

These observations offer insight into the life history and behaviour of this rarely-seen anole species. Hopefully, with the continued work of Indigo Expeditions and the guides at Estación Biológica Las Guacamayas we’ll learn more about these interesting reproductive behaviours in the future.

The Horned “Rhino Lizard” of Sri Lanka

By Jonathan Losos

On April 3, 2017

In All Posts

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 stoddardi. Anima 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

By Jonathan Losos

On April 1, 2017

In All Posts

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!

Back cover of Anoles of Honduras

Dewlap Design Facilitates Recognition But Not Detection: a Field Test Using Robots

By Danielle Klomp

On March 30, 2017

In All Posts

The use of programmable robots (‘mechanical models’ is more accurate) to minimise disturbance while observing wildlife, or to run behavioural experiments in the field, has slowly increased in the last decade and studies across many taxa have utilized this approach (Martins et al., 2005; Partan et al., 2009; Cianca et al., 2013; Macedonia et al., 2013; Clark et al., 2015). I’d argue that “robots” are one for the most important tools for behavioural ecologists studying communication or display behaviour, as they are one of the few ways in which we can conduct field-based experiments – mimicking or manipulating animal behaviour, colour or morphology in any way – in the animal’s natural environment.

We recently published a paper in the Journal of Evolutionary Biology, using robots in playback experiments to test the importance of ornament design for signal detection and conspecific recognition.

Many factors potentially affect signal design, including the need for rapid signal detection and the ability to identify the signal as conspecific. As understanding these different sources of selection on signal design is essential in the larger goal of explaining the evolution of both signal complexity and signal diversity, here we assessed the relative importance of detection and recognition for signal design in the Black-bearded gliding lizard, Draco melanopogon (fig. 1). Lizards of the species-rich genus Draco use large extendible dewlaps for communication, that differ in colour pattern and size between species – in a similar fashion to the anoles.

Figure 1 A. Male D. melanopogan, dewlap naturally extended (image a still from behavioural trials) and the angle of dewlap extension as measured from still; B. robot, dewlap treatments (Bi) solid colour and Bii) two-coloured); and C. artificially extended dewlaps of a male and female D. melanopogan.

To test whether the dewlap colour and pattern function more to facilitate 1. signal detection and 2. conspecific recognition, we presented free-living lizards with robots displaying dewlaps of six different designs, varying in the proportion of the black and white components.

In this case, our robots were just ‘visual flags’ that mimicked the dewlap size and shape, as well as the speed and display pattern of live Draco melanopogan lizards (video 1). Having only the dewlap / visual flag and not the rest of the lizard body allowed us to look solely at the salience of the dewlap colour and pattern itself – without adding any identifying or qualifying information in the form of a body.

Video 1: ‘The floating dewlap’

Our experiment had six colour treatments ranging from “natural” (population typical design, fig. 1) to unnatural (wrong colour, no pattern) – and from very conspicuous (high internal contrast and high contrast against the background for each colour) to very inconspicuous (matching the luminance of the background). Thus, we could test both the ‘detection’ and ‘conspecific recognition’ hypotheses with the same set of treatments.

Predictions for Hypothesis 1: We predicted that should the dewlap colour pattern function in signal detection, that more conspicuous dewlap treatments would be detected sooner than less conspicuous dewlaps. Each of the two-coloured treatments were more conspicuous than the single-coloured treatments, as they had the same high contrast black and white elements, but they also had the high internal contrast of the black against the white (75.02 JND). Provided the receiver has sufficient visual acuity at the viewing distance to be able to distinguish the two colours from one another, internal contrast increases signal conspicuousness, and the more equal the two adjacent colour patches are in size (i.e. 50% of the dewlap black – 50% of the dewlap white) the greater the internal contrast. There is no existing data on the visual acuity of Draco lizards, so for this experiment we stuck to the natural dewlap size and viewing distances, with small oscillations around the natural proportions of black and white.

Predation of a Gecko by Anolis pulchellus in the British Virgin Islands

By James T. Stroud

On March 28, 2017

In Natural History Observations, Notes from the Field

In the most recent issue of Herp Review, Anole Annals stalwarts Kevin de Queiroz and Jonathan Losos documented their account of observing an adult female grass-bush anole (Anolis pulchellus) consume a dwarf gecko (Sphaerodactylus macrolepis) on Guana Island, British Virgin Islands. The authors share their detailed report below:

Many primarily insectivorous lizards will eat other vertebrates on occasion, a behavior that has been reported in many species of Anolis. One unifying generality is that such carnivory is size structured, with the predator usually being substantially larger than the prey (Gerber 1999. In Losos and Leal [eds.], Anolis Newsletter V, pp. 28–39. Washington University, Saint Louis, Missouri). Not surprisingly, reports of anole carnivory pertain primarily to middle-sized and larger anoles. Here we report carnivory by a small anole of the species A. pulchellus. To our knowledge, this is the first instance of carnivory reported for this species and one of few for any similar-sized anole (the record noted by Henderson and Powell 2009. Natural History of West Indian Reptiles and Amphibians. University Press of Florida, Gainesville, Florida. 495 pp. is based on the observations reported here).

Fig. 1. Female Anolis pulchellus in the process of ingesting a
Sphaerodactylus macrolepis.

We observed a female A. pulchellus (SVL ca. 38 mm) capture and consume a Sphaerodactylus macrolepis (SVL ca.18 mm) in the leaf litter at approximately 1430 h on 25 September 2006, on Guana Island, British Virgin Islands, near the head of the Liao Wei Ping Trail at roughly 18.47916°N, 64.57444°W (WGS 84). The anole jumped from a low perch (ca. 20 cm above the ground) to the ground and bit the gecko, which escaped and fled 15–20 cm to the opening of an ant nest. The anole attacked the gecko again, seized it in its mouth and carried it approximately 10 cm up a vine, a distance of 15–20 cm from the site of attack. Initially, the anole held the gecko upside down (i.e., dorsal surface facing down), biting it between the fore and hind limbs on the left side. Eventually the anole worked its grasp posterior to the base of the tail, still on the left side. At this point, parts of both the base of the tail and the left hind limb were in the anole’s mouth (Fig. 1). The anole then manipulated the gecko so that it was no longer upside down, but rotated about its long axis by roughly 90 degrees (the ventral surface of the gecko was then oriented forward relative to the anole) at which point it was biting the gecko at the base of the tail and possibly by the left hind limb; the anole eventually manipulated the gecko so that it held it tail-first in its mouth, dorsal side up, at which point the anole proceeded to ingest the gecko tail first (during this time, the tail itself broke off and was carried away by ants, which had been biting the gecko in several places since shortly after it was
captured by the anole). Total time from capture to complete ingestion was approximately five minutes.

Predation on Sphaerodactylus geckos has been reported in anoles of only a few species, none of which are as small as Anolis pulchellus (Henderson and Powell 2009. Natural History of West Indian Reptiles and Amphibians. University Press of Florida, Gainesville, Florida. 495 pp.). However, given the size discrepancy between the lizards in these two clades and their extensive coexistence across the Caribbean, we suspect that such interactions may occur with some frequency. Moreover, the high population densities of some Sphaerodactylus geckos (e.g., Rodda et al. 2001. J. Trop. Ecol. 17:331–338) and the diurnal activity of several species (Allen and Powell 2014. Herpetol. Conserv. Biol. 9:590–600) suggest that they may be important prey items for anoles.

References
– Allen, K.E. and Powell, R., 2014. Thermal biology and microhabitat use in Puerto Rican eyespot geckos (Sphaerodactylus macrolepis macrolepis). Herpetological Conservation and Biology, 9(3), pp.590-600.
– Gerber 1999. In Losos and Leal [eds.], Anolis Newsletter V, pp. 28–39. Washington University, Saint Louis, Missouri
– Henderson and Powell 2009. Natural History of West Indian Reptiles and Amphibians. University Press of Florida, Gainesville, Florida. 495 pp.
– Rodda, G.H., Perry, G.A.D., Rondeau, R.J. and Lazell, J., 2001. The densest terrestrial vertebrate. Journal of Tropical Ecology, 17(02), pp.331-338.

Anole Embryos Don’t Mind the Heat

By Putter Tiatragul

On March 26, 2017

In Introduced Anoles

Adult male A. cristatellus in survey position on a tree next to an urban street. Photo credit: Renata Brandt

Walking down “Red Road” in Pinecrest neighborhood of Miami, FL, it is hard to miss a myriad of lizards on trees and street lamps. Among the many city-dwelling residents, the Cuban brown anole (A. sagrei) and the Puerto Rican crested anole (A. cristatellus) are seen virtually everywhere. While there is evidence that anoles are adapting to urban landscapes, most past studies have focused on adult stages (Kolbe et al., 2012; Winchell et al., 2016; Lapiedra et al., 2017) and early life stages have been largely ignored. Our recently published study in the Journal of Thermal Biology (Tiatragul et al., 2017) was the first to address how anole embryos could facilitate establishment of populations in cities.

The transformation of natural habitats into urban landscapes dramatically alters thermal environments, which in turn, can impact local biota. For ectothermic organisms that are oviparous (like anoles), developing embryos are particularly sensitive to these altered environments because they cannot behaviorally thermoregulate and are largely left to the mercy of their surrounding environment. Yet, we know little about how thermal environments in urban and forested areas affect embryo development and hatchling phenotypes.

Mean incubation duration is shorter when eggs are incubated at urban temperatures (hotter). See publication for full results.

To determine if embryos from urban and forested sites are adapted to their respective thermal environments, we incubated eggs with temperature regimes that mimic likely nest conditions in both urban and forested environments. Our results show that for two species (A. sagrei and A cristatellus), urban thermal environments accelerated development, but had no impact on egg survival or any hatchling phenotypic traits measured (including body size, running performance, and locomotor behavior). Furthermore, there is no evidence that embryos from either habitat are adapted to their respective thermal environments. Rather, this lack of major effects suggests that both anole species are physiologically robust to novel environments. This may explain their success in establishing populations in human-modified landscapes.

Physiological adaptation by embryos are not required for a population to establish successfully. Maternal behaviors, like maternal nest site selection could shield embryos from lethal conditions. Hence, our next study is going to involve quantifying maternally selected nest sites in the urban and forested landscapes.

Lizard Signals Adapt to the Environment: Habitat-Dependent Variation in Motion Signal Structure between Lizard Populations

By Jose Ramos

On March 24, 2017

In All Posts

Habitat characteristics influence the efficacy of animal signals, which means that populations of the same species occurring in distinct habitats are likely to show differences in signal structure as a form of local adaptation. This kind of variation in signal structure has been well-studied for sound and colour signals, including in several species of anoles, but had not been reported for motion-based signals until recently.

Jacky dragons (Amphibolurus muricatus) are Australian agamid lizards well-known for the complex motion-based displays performed by males. These displays comprise five distinct motor patterns utilised in sequence: tail flicks, backward limb wave, forward limb wave, push up and body rock (A. muricatus display video). A study conducted by Barquero et al. (2015) found evidence of temporal and structural variation in the core display of three populations of A. muricatus. These differences were not related to genotypic differences between populations, so they suggested they might be a consequence of local habitat structure.

The Jacky dragon

Concurrently, Richard Peters and I were developing a methodology to accurately quantify the effect of background noise on the motion based signals of different Australian agamids (see Ramos & Peters 2017a; b). Our approach calculates the speed distributions of the motion produced by lizard signals and the environmental noise independently. It then compares these distributions to obtain a measure of signal-noise contrast. This is accomplished by recording lizard behaviour and reconstructing its motion in three dimensions before comparing it against the motion produced by the surrounding windblown plants, which are the main source of noise for motion based lizard signals. This methodology stands out from other approaches for quantifying motion signals because it does not assume that the camera is ideally placed when recording the displays, but instead provides an accurate representation of the motion from any angle or viewing position.

Building upon the work by Barquero et al. (2015), we applied our novel approach to a couple of populations of Jacky dragons with distinct habitat characteristics. Croajingolong National Park in Victoria (Australia) is densely vegetated coastal heath with tall grasses and shrubs on a sandy substrate. Conversely, Avisford Nature Reserve in New South Wales (Australia) is mostly open woodland with an understory of scattered grasses and small shrubs, and rocky outcrops spread throughout the park.

The habitats of (a) the Jacky dragon. (b) Croajingolong National Park, in coastal Victoria, Australia. (c) Avisford Nature Reserve, in New South Wales, Australia.

Our results revealed that lizards from the densely vegetated habitat (Croajingolong NP) performed displays of longer duration and introductory tail flick components, and also produced a significantly greater amount of high speeds. However, when we calculated the signal-noise contrast for both populations at their respective habitat, we found no difference. This means that the signals from both populations are equally effective when used within their intended habitat, regardless of their structural differences.

Differences in signal structure between populations. (a) Mean bout and tail flick durations for both lizard populations. (b) Mean tail flick to bout ratio for both lizard populations. (c) Average kernel density functions for both lizard populations.

As mentioned before, our approach records animal signals and environmental noise independently, which allowed us to consider signals not only in the environment where they were filmed, but also in the habitat of the other lizard population. Consequently, to highlight the effects of the environment on lizard signals, we calculated signal-noise contrast for the signals belonging to one population in both habitats (densely vegetated vs. open woodland). As expected, both lizard populations performed worse in densely vegetated habitat, probably because the complex understory is producing greater motion noise and negatively affecting signal efficacy. Another way of looking at these data, but this time focusing on the displays rather than the habitat, was to compare the signal-noise contrast of both lizard populations in a single habitat. Lizards originating from the densely vegetated habitat produced higher contrast scores in both habitats, indicating that their displays are more effective overall.

Taken together, our results are consistent with the local adaptation hypothesis. Lizards from Croajingolong NP produce displays with longer durations and characterised by faster speeds in order to communicate effectively in a dense and noisy habitat. Conversely, lizards from Avisford NR have adapted to a less noisy environment and do not require such lengthy or energetically expensive displays. Such population level differences in signal structure due to habitat variation represent novel findings for motion-based lizard signals.

Reporting on the Reptiles of Redonda

By Colin Donihue

On March 22, 2017

In All Posts

I’m back from Redonda and the expedition was a great success! I’m happy to report there were many Anolis nubilus boulder-hopping out of the way of the black rats and even blacker ground lizards on the island. In many ways the trip was even more challenging than expected but we came out with quite a lot of data so we have a great sense of the current status of the reptiles on the island and a baseline for comparisons into the future. I have even more stories and some videos going up on my blog to keep watch over there if you want even more details about Redonda.

To refresh your memories, Redonda is an island of Antigua and Barbuda and was completely denuded by rats and goats over the last century. Despite the dearth of vegetation, three endemic reptiles had been hanging on: Anolis nubilus, Ameiva (Pholidoscelis) atrata, and an as-yet unnamed Sphaerodactylus dwarf gecko. The government of Antigua and Barbuda, in collaboration with Fauna & Flora International and local NGO the Environmental Awareness Group, has decided to undertake a massive restoration effort by eradicating the rats and relocating the goats. My job was to get some baseline data on the current lizard populations so we can figure out how they change into the future.

Helicoptering to the island was every bit as exciting as I’d hoped. The Jurassic Park theme was playing through my head the whole way down. See that grassy patch with slightly fewer large rocks – that was the little tiny helipad, but our pilot was a pro and set us down perfectly. Almost as soon as we were out of the helicopter, we deposited our bags by our tents and set about catching Anoles.

Anolis nubilus is at first blush a relatively innocuous member of the genus. They’re perfectly camouflaged in this environment, which is to say they’re drab gray and brown. Their dewlaps are cream-colored (which is really just my nice way to say drab gray-yellow) and the most decorated of the females sport faint dorsal stripes. Males did fairly regularly display impressive crests behind their heads, but nonetheless, the species at first and second glance is considerably less flashy than many of their cousins on nearby islands.

Photo: Geoffrey Giller

All that said, there’s still a lot of cool stuff going on with nubilus. As Skip mentioned in his article 45 years ago, there’s a casuarina tree right next to the remains of the mine manager’s house that hosts an abundance of the few Redonda tree lizards living up to their name. The tree is still there and the lizards are still eagerly defending their precious few branches (see above).

There are actually quite a few trees still on Redonda, some of which are native Ficus trees. For the most part they’re in fairly inaccessible areas, but that really just means you need to bring a longer noose pole and don’t look down. I caught a lizard on this tree below with a perch height of approximately 350 meters (that’s really going to mess with the averages). Truth be told, after catching the lizard my knees were so wobbly I had to go find a nice big boulder and just had Geoff and Anthony shout me data for a while.

After a week on the island and many, many Anoles, we got morphometric and performance data, diet data, extended focal-animal behavior videos, two mark-recapture density studies and two permanent transects established, thermal ecology data, habitat use data, and flight behavior data. We even exhaustively determined whether nubilus likes Chuckles! (But that’s a story for another post).

I know this is an Anole blog, but there were some pretty cool things going on with the other reptiles on the island, too. The ground lizards were jet black and really big. Here’s a picture of Anthony Herrel trying to get a tail measurement:

Photo: Geoffrey Giller

The atrata spent their days cruising around scavenging. We saw one eating a hermit crab, and we heard rumor of another that managed to get a sardine away from one of the crew working on the eradication effort! Analyzing the stomach contents of these guys is going to take quite a lot of detective work.

We also were able to gather the first natural history data on this unnamed dwarf gecko species. They’re strangely beautiful with an unlovely shovel-face and semi-transparent, too-squishy, gelatinous body. You wouldn’t guess it but they’re quick!

Photo: Geoffrey Giller

In all, the reptiles of Redonda were fascinating and getting to explore the island was a unique privilege. I can hardly wait to return next year, and many years after, to see how the lizards change with the island.

“What about us?” Technically these guys are reptiles too, but c’mon, the lizards are so much cooler. Photo: Geoffrey Giller

A Bit of Extra Swag? Unusual Color Spot on a Brown Anole

By Joshua Hall

On March 20, 2017

In All Posts

Figure 1. Male brown anole with an unusual orange spot on the shoulder.

In the past, numerous anole enthusiasts have posted photos of atypical color variants (1, 2, 3, 4). While sampling small spoil islands in the intracoastal waterway last October, I caught a male brown anole with an unusual splash of color on the shoulder (Fig 1). Reports of sagrei that are completely orange have been noted (5, 6); however, those animals appear to represent a more intense version of the ‘rusty red’ that many of these lizards commonly display on their bodies, particularly on the head. The orange on this male, however, is unlike anything I’ve seen on a brown anole, save for the coloration outlining the dewlap. I’m curious to know if anyone has seen something like this before.