Tag: brown anole Page 1 of 2

#DidYouAnole – Anolis sagrei

On December 3, 2020

Photo by Alan Franck, iNaturalist

Hey!

Since we had some questions about tail curling in Brown Anoles last week, I figured we should just talk about them today!

Anolis sagrei, or the Brown Anole or Bahaman Anole, is a trunk-ground anole whose range originally included islands like the Bahamas, Cuba, and the Cayman Islands. Brown Anoles are great stowaways and have now made it to the mainland US, other Caribbean islands and Pacific islands like Hawaii.

Brown Anoles can get up to 8.5 inches long (including their tail), and have a snout-to-vent length of about 55-60mm. They are, as their name suggests, often brown, but may also be grey. Despite the drab colouring, these anoles have a lot of variation in their patterns between individuals, with some almost looking plain and others appearing very striking with an array of spots, striping and marbling. Brown anole’s dewlaps are typically red-orange with a yellow border, but there are some who have splotches of yellow.

Since the introduction of another brown coloured anole, Anolis cristatellus (the Crested Anole), the two may be confused, but Brown anoles can be differentiated from them by the dewlap colouring (Crested anoles have opposite dewlap colours, typically yellow with a usually large border of orange), and if you can get close enough, by the presence or absence of light coloured ring around the eye or front limb stripe. Brown anoles don’t have this ring, but instead have dark eye bars (I like to think of it as winged eyeliner, that’s just how it registers the fastest in my mind). They also don’t have a light stripe above their front limb. Female Crested anoles have only a cream-coloured stripe down their backs that Brown anole females might have between diamond or bar patterning.

As we all may know ,they’re also very feisty anoles, going after questionable prey and prey larger than themselves. They are also one of several anoles that eat other anoles (and other lizards)!

Photo by Gecko Girl Chloe, iNaturalist

In the pet trade, Brown anoles with red/orange colouring are called Flame morphs, and lucky for you here’s a study on why that red might be showing up.

Photo by Sam Kieschnick, iNaturalist

I also get a lot of questions on Brown and Green anole interactions, typically about why Brown anoles are killing off Green anoles and here’s some posts to help answer that!

SICB 2020: Acute Interactions between Green and Brown Anoles

By Chris Robinson

On January 9, 2020

In All Posts

Jordan Bush giving her talk on the interaction between green and brown anoles at SICB 2020

Green and brown anole interacting within Jordan’s enclosures.

As brown anoles (Anolis sagrei) become more and more abundant, many people (trained and citizen scientists alike) are intrigued with exactly how the native green anole (A. carolinensis) will respond. Newspaper articles still report on these interspecific interactions, and some recent research has shown the brown anoles can be quite mean to the native green. Thankfully, it seems that the green anole may simply be moving higher into the canopy and aren’t being merely driven to extinction by the invading brown. However, we do not yet understand the nuances of how green anoles respond when brown anoles first arrive to a new location, and that’s where Jordan Bush, a sixth year PhD student in Dan Simberloff’s lab at the University of Tennessee, Knoxville, comes in.

To understand how green anoles immediately react to the novel presence of brown anoles, Jordan built 5 x 5 x 5m enclosures in which she placed 6 female and 6 male green anoles. These animals then set up territories and became acclimated to their new living space. Jordan quantified baseline behavior and territory sizes (in 3D!!!) for each individual in an enclosure.

Example 3D territories

After 10 days, Jordan introduced brown anoles in these enclosures, either two females and two males or four females and four males to investigate the effects of density, and quantified behavioral and territorial changes in the green anole. Being the careful researcher that she is, she also introduced the same number of green anoles to other enclosures so that she could show that any changes in behavior were not simply due to more animals being present. After 10 days of interacting with the brown anole, Jordan found no change in activity level, home range volume, or perch height, suggesting that, at least within an acute time frame, the green anole can handle its own against the brown anole.

SICB 2020: Collecting Ecological Data from iNaturalist Observations: an Example with Anolis Lizards

By Laura Taylor

On January 9, 2020

In All Posts

Chris Thawley presenting his work at SICB 2020

Citizen science is a collaboration between scientists and the general public to advance scientific research. A major citizen science project is iNaturalist. In iNaturalist, anyone can submit an observation of an organism, which includes the date and location. It provides a database over a large area and a long time that would be extremely costly for scientists alone to collect. However, the data’s suitability for ecological analysis is uncertain.

To shine some light on the robustness of citizen science data, Chris Thawley, a visiting assistant professor at Davidson College, worked in collaboration with Amy Kostka, an undergraduate at the University of Rhode Island. When the project was developed, Chris was a postdoc in Jason Kolbe’s lab at the University of Rhode Island. As Amy was unable to go into the field, iNaturalist provided the perfect opportunity for her to experience the research process. They decided to compare established hypotheses of native green anoles (Anolis carolinensis) and invasive brown anoles (Anolis sagrei) against the iNaturalist data. They first coded the anoles’ sex, habitat use, behavior, and morphology, and then compared their coded data against existing hypotheses.

Overall, they found that the iNaturalist data corresponded with existing hypotheses of green and brown anoles. Male brown anoles displayed more frequently than male green anoles, in accordance with results in this paper. Males had broken tails more frequently than females regardless of species, likely due to the more risky behaviors conducted by male anoles than females anoles. Green anoles perched more frequently on natural substrates and perched more frequently in a vertical orientation than brown anoles, in accordance with findings by Stuart et al. (2014). Additionally, the brown and green anoles’ reproductive time period (as measured by when hatchlings emerged) matched with the literature.

iNaturalist is a fantastic tool for individuals who are unable to conduct fieldwork, but still want the research experience. However, Chris pointed out that iNaturalist has spatial biases towards urban areas and temporal biases towards the present day. Additionally, it is necessary to sort and clean the data and to train individuals to standardize coding. This study demonstrates that iNaturalist is still a powerful tool and can be used to estimate phenological patterns, differences between sexes, and corroborate existing hypotheses. Chris hopes that, in the future, iNaturalist could be used to generate new hypotheses.

SICB 2020: Brown and Green Anoles Have Similar Activity Levels Across Temperatures

By Chris Thawley

On January 7, 2020

In New Research

Brown anoles (Anolis sagrei) are found in many urban habitats.

Invasive species are a common ecological issue worldwide. In certain situations, they can prey on, outcompete, or otherwise disrupt the ecology of native species, potentially leading to population declines or extirpation.

The brown anole (Anolis sagrei) is native to Cuba and surrounding Caribbean islands, but has been repeatedly introduced to mainland North America via Florida over the past ≈100 years. Brown anoles have continued to spread and now occupy most of Florida, along with areas of the Gulf Coast. These anoles are particularly adept at exploiting urban habitats, such as Houston and New Orleans, where they may attain higher body size and compete with the native green anole (Anolis carolinensis). Brown anoles can outcompete green anoles in habitats such as the ground or lower levels of vegetation, where they can use their larger, more muscular bodies to chase off the native anoles or even prey on young green anoles. While green anole populations are likely not extirpated by brown anoles, they shift their locations higher into vegetation, to avoid competition with brown anoles.

The ability of these species to maximize their activity at different temperatures may play a role in determining the outcomes of interactions between brown and green anoles. While green anoles are present throughout the southeastern US and can tolerate colder temperatures, brown anoles may be ancestrally adapted to higher, more tropical temperatures. Lucy Ryan, a masters student in the Gunderson Lab at Tulane University decided to investigate this possibility by monitoring the activity levels of each species at a variety of different temperatures. The research team hypothesized that, based on their thermal preferences, brown anoles would have higher activity levels than green anoles at both higher temperatures and over a wider range of temperatures. Lucy conducted focal observations of anoles to quantify activities such as feeding, displaying, and moving. They measured the temperature of each anole’s microhabitat with a copper model containing a thermocouple.

Over an 18° C range of temperatures, Ryan found that there was no difference in the activity levels of the two species. These results, while surprising, suggest that effects of temperature on activity are not driving the competitive advantage of brown anoles over green anoles. In fact, since both species’ activity rates peak at similar intermediate temperatures, this situation may increase competition between brown and green anoles. Ryan plans to continue this work through the winter and spring to determine whether there are any species differences over an entire year of activity which may impact this system. Stay tuned and follow them on Twitter!

Green anole activity rate, including dewlap displaying, shows a peak at intermediate temperatures.

SICB 2020: Green Anoles Have Higher Heat Hardening Capacity Than Brown Anoles

By Chris Thawley

On January 6, 2020

In New Research

Ectotherms rely on interactions with surrounding thermal environments to regulate their body temperature. If their body temperatures get too low or too high, ectotherms may be unable to move effectively or escape dangerous temperatures, potentially leading to death. One plastic physiological response which may help ectotherms avoid the effects of dangerously high body temperatures is heat hardening. Heat hardening is a type of physiological flexibility that entails an organism increasing its heat tolerance after a previous exposure to high temperatures. In areas with high temperatures, differences between ectotherms in their abilities to effectively conduct heat hardening could affect competition between them.

A green anole (Anolis carolinensis) basks at an elevated perch.

Sean Deery, a masters student in the Gunderson lab at Tulane University, chose to investigate heat hardening capacity in two species of anoles, the native green anole (Anolis carolinensis) and the invasive brown anole (Anolis sagrei), both of which are present in New Orleans. As brown anoles have expanded throughout the area, they have displaced green anoles, forcing them higher into vegetation, a pattern repeated in other areas of the southeastern U.S.

Brown anoles are particularly adept at exploiting urban habitats, where temperatures may be considerably higher than surrounding natural areas due to the urban heat island effect. Sean wondered whether the competitive advantage of brown anoles over green anoles might be based in part on a superior heat hardening capacity, which could support their dominance in urban areas.

(a) A male green anole and (b) and a displaying male brown anole in Florida.

To quantify heat hardening in this system, Sean captured green and brown anoles and first measured their upper critical thermal maximum (CTMax) by steadily ramping up their body temperatures until the lizards lost coordination. CTMax represents a temperature that could prove lethal to a lizard as it would be unable to escape these hot conditions. After allowing lizards to recover, Sean measured their CTMax again after periods of 2, 4, and 24 hours. Heat hardening was calculated as the difference between the initial CTMax and the subsequent measurement after exposure to those initial high temperatures.

Sean’s results were surprising: He found that brown anoles showed no evidence of heat hardening at any time after an initial measurement of CTMax. In fact, brown anoles showed a reduction in CTMax, suggesting that the initial testing may have stressed them and reduced their ability to cope physiologically with higher temperatures. Green anoles on the other hand showed a moderate heat hardening response, with significant increases in CTMax just 2 hours after exposure to high temperatures. Sean’s results also suggest that individual lizards with lower initial CTMax values showed greater heat hardening.

For now, it appears that heat hardening is not a factor driving invasions of brown anoles in the southeastern U.S., but the differences between these two species are intriguing. Sean hopes to expand on this work by investigating molecular mechanisms that may support or inhibit heat hardening, such as expression of heat shock proteins.

SICB 2019: The Life and Death of an Extralimital Population of Invasive Brown Anoles

By Chris Thawley

On January 6, 2019

In New Research

Brown anoles are invasive throughout the southeastern United States and are often transported via the nursery trade.

As invasive species expand across landscapes, they may engage in new interactions including with native competitors and prey as well as encountering novel environmental conditions such as different temperatures or patterns of rainfall. It is often difficult to observe the process of how invasive species which are dispersing across landscapes are affected by these novel conditions, because it may be difficult to find edge populations of invaders, and those extralimital populations which do not survive may have disappeared before scientists can observe them.

In southern Florida, many anole species have been introduced and are expanding their ranges, perhaps none more prolifically so than the brown anole (Anolis sagrei). In the past 75 years or so, brown anoles have occupied all of peninsular Florida, the eastern seaboard of Georgia, and Gulf Coast habitats through Louisiana. Many of these expansions are thought to occur via hitchhikers on cars or via the nursery trade, in which potted plants with adults or eggs are transported to new areas. These introductions may fail for many reasons (e.g., inhospitable environments, low numbers of colonizers, intentional extirpation by humans), but these processes of dispersal, establishment, and extirpation are difficult to study. Dan Warner, a professor at Auburn University, took advantage of a known extralimital population of brown anoles in a greenhouse in central Alabama to study the survival of a population created through this type of dispersal.

This population of anoles existed well north of its continuous invasive range in the United States and was exposed to much colder winter conditions than other studied populations. It was present at the greenhouse from at least 2006, and so survived for at least 10 generations, long enough for adaptation to these novel thermal conditions to potentially occur. Working with a team of undergraduates, graduate students, and post-docs, Dan assessed the thermal conditions in the greenhouse environment, conducted mark-recapture studies of the population, and measured thermal tolerances of lizards.

Dr. Amélie Fargevieille and Jenna Pruett representing the Warner Lab at SICB 2019.

At SICB 2019, Dr. Amélie Fargevieille and Jenna Pruett presented results from the study, showing that the greenhouse population included all life stages of lizards and reached a total size of >1000 individuals. While one might expect that these northern lizards would have altered critical thermal limits, the Warner lab showed that both the upper and lower thermal limits of these lizards (the temperatures at which their movements became uncoordinated), were the same as those found in lizards from warmer, southern populations. These results indicate that existence in a colder northern climate for >10 years did not lead to adaptive changes in thermal limits, perhaps due to the population occupying a thermally-buffered habitat, i.e., the greenhouse.

While hurricanes have facilitated several fascinating studies of anole adaptation (e.g., Schoener et al., 2017, Donihue et al., 2018), they may also take these opportunities away. In the case of this population, Hurricane Irma blew off the greenhouse roof in 2017 (which remained unrepaired), exposing this population to the rigors of a central Alabama winter. Multiple surveys in 2018 confirmed that there were no survivors of this previously robust population. Dataloggers confirmed that, even in the most sheltered microhabitats that remained, temperatures dropped below the critical thermal minima of brown anoles, presumably extirpating the entire population.

Recent Extinction of a Viable Tropical Lizard Population from a Temperate Area WARNER, DA*; HALL, JM; HULBERT, A; TIATRAGUL, S; PRUETT, J; MITCHELL, TS; Auburn University.

JMIH 2017: Removal of Curly-tailed Lizards Increases Survival of Urban Brown Anoles

By Chris Thawley

On July 16, 2017

In New Research

Interspecific Interactions Between Two Species of Invasive Lizards in an Urban Environment; Camila Rodriguez-Barbosa and Steve Johnson

An extensive body of work has addressed the eco-evolutionary impacts of the Northern Curly-tailed Lizard (Leiocephalus carinatus) on Brown Anoles (Anolis sagrei) (much of it receiving coverage right here, here, and here on Anole Annals!). These species co-occur not only on many Caribbean islands where much of this research has taken place, but also within the urban matrix of southern Florida, where both species are introduced.

Camila Rodriguez-Barbosa and Steve Johnson investigated the impacts of curlies on brown anoles in shopping centers in southern Florida where both species were plentiful. Camila first collected baseline data on anole and curly populations at eight sites before embarking on a quest to eliminate curlies from four of her sites. Over the next four months, she removed over 300 (!) curlies from these sites, many of which had brown anole remains in their stomachs.

She found that this removal had serious consequences for brown anoles. Compared to anoles from shopping centers where curlies were unchanged, A. sagrei at removal sites experienced higher survival and consequently greater abundances. These anoles also shifted to lower perches once curlies were removed, mirroring results from previous work which show that the introduction of curlies leads to brown anoles occupying higher perches to escape this dangerous predator. Camila’s work suggests that brown anole/curly-tailed lizard interactions may be similar even in very different habitats and provides a fascinating look at lizard life (and death) in the urban sprawl of southern Florida.

JMIH 2017: Brown Anole Reproductive Output Varies Seasonally

By Chris Thawley

On July 16, 2017

In New Research

Tim Mitchell, Josh Hall, and Daniel Warner: Seasonal Shifts in Anolis sagrei Reproduction Invoke Challenges for Scientific Reproducibility

Sometimes a scientist just needs hundreds of hatchling anoles for an experiment. Tim Mitchell found himself in this position recently, and, like a good lizard ecologist, he started breeding colonies of anoles in the lab to produce eggs to incubate until hatching. As he created three different breeding colonies from brown anoles (Anolis sagrei) in central Florida, one each in February, June, and September, Tim found that he had also created an ideal situation in which to examine how the reproductive condition and output of brown anoles varies across the breeding season.

Tim, along with his coauthors Josh Hall and Dan Warner, found that females produced eggs with significantly greater mass later in the breeding season. These eggs took longer to produce than those earlier in the year (a greater interclutch interval), and the eggs resulted in hatchlings that had higher mass in relation to the weight of their eggs. These reproductive differences remained even after accounting for the fact that female anoles were also larger and heavier later in the year.

These findings suggest that female A. sagrei may shift their reproductive effort from producing a higher quantity of eggs (i.e., more, smaller eggs resulting in smaller hatchlings) in the beginning of the breeding season, to producing higher quality eggs (i.e., fewer, larger eggs resulting in larger offspring) later in the breeding season. Tim’s findings also stress the importance of investigating and accounting for seasonal differences when examining reproductive output in lizards.

Female Brown Anole Inspecting Nest Pot

By Renata Brandt

On June 15, 2017

In Anole Videos

It is not new to most of us that female lizards choose between different nest sites (e.g. Shine & Harlow, 1996; Warner & Andrews, 2002), anoles included (Socci et al., 2005; Reedy et al., 2012 – covered on Anole Annals). But what is new to me is how females assess soil characteristics to decide where to lay their eggs.

Brown anoles in an intimate moment.

For context, I recently started to breed brown anoles in the lab for the first time. I’m using large vertical screen cages in an outdoor set up, which I believe makes them pretty comfortable to keep their daily anole life. There have been lots of male-male interactions (displaying and serious fights), mating and nesting.

A few days ago I started to notice females head down in the nests pots, breathing heavily from time to time. I wondered if they were inspecting the nest pots before laying and shared a video on Twitter. They take a long time in that position, which made me really curious to know how they assess their chosen nest-site characteristics. Let me know if you know more about it. Posted above is the video I uploaded to youtube.

I feel so lucky to be able to observe all these cool behaviors and I hope to share some more soon!

Brown Anole Predation by Red-bellied Woodpeckers in Florida

By James T. Stroud

On March 22, 2016

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

While visiting relatives last week in Fort Myers (FL), anole enthusiast and avid wildlife photographer Kyle Wullschleger noticed a commotion among the trees while on an afternoon hike in a small neighbourhood nature preserve. On closer inspection he witnessed a group of red-bellied woodpeckers (Melanerpes carolinus) foraging on surrounding cypress trees, with a couple eventually appearing with their apparent target–non-native Cuban brown anoles (A. sagrei). He recalls some of the details:

“The photos from the sequence aren’t all that fantastic because I cropped in so it really just shows the behavior. The whole sequence the woodpecker was basically just slamming the anole against the tree and then trying to pick it apart – it was hard to tell what exactly it was doing, but I believe it eventually swallowed it whole before flying away–it hopped behind the tree so I couldn’t see it anymore.”

“There were at least five birds all moving up and down the lower third of the cypress trees just around the boardwalk I was on. They were moving around the trees without really knocking the wood, so maybe they were purposefully targeting anoles? I only saw successful predation twice, but the brush is so thick–it’s obviously happening quite a bit.”

Sean Giery had previously discussed the main avian predators of anoles in urban South Florida, but woodpeckers didn’t make the list. Woodpeckers do occur in urban areas of South Florida; a new one to add to the list?