Here is a short film I made concerning green and brown anoles in Florida and their behaviors and physical differences. Follow me on Instagram @dailyanole!
Photo by Jake Scott, iNaturalist
Hello again!
Hope you all are doing great. I just finished my finals and two applications to PhD programs (so far) so fingers crossed for me???
I wanna talk about another (mostly) brown-coloured anole today since I feel like there’s not enough appreciation for them.
Anolis distichus, the Bark Anole, is a trunk anole with about 16 subspecies, that ranges in colour from brown to grey to green. Their dewlaps also vary in colour and pattern with their population. Males and females look the same, but in this species only males have a dewlap.
Found in Haiti, Dominican Republic, central Bahamas and, of course, Florida, these anoles can be found in range of habitats. Bark anoles are kind of on the small side at about 127mm in length.
My favourite thing about the Bark Anole is the patterning that gives it its name. The striping mimics the roughness and shapes found in tree bark, making it kind of invisible sometimes. Quite an example of perfect camouflage.
Photo by alyssa_marker16, iNaturalist
Photo by alyssa_marker16, iNaturalist
There’s been a lot of research on the anole, particularly looking into its subspecies and if any of them are their own species. Currently, this doesn’t seem to be the case quite yet.
Maybe. There’s a lot of conversation about just how much variation there is or isn’t with this species.
Photo by djhiker, iNaturalist
1st place: Two Anolis lineatus by Matthijs van den Burg.
Aryeh Miller and Ansley Petherick
Thank you once again to everyone who participated in this year’s Anole Annals photo contest! We received over 400 total votes from 14 different countries, and now we’re ready to announce the results. First up, the grand prize winner, is the above photo of two Anolis lineatus from Aruba taken by Matthijs van den Burg. The second place winner is below, Anolis polylepis from the Osa Peninsula of Costa Rica, by Anna Thonis. Congratulations!
2nd place: Anolis polylepis by Anna Thonis.
The rest of the winners are below, and their photos can be seen in the 2021 calendar here! Click the link to order your calendar.
Congrats again to all the winners, and happy holidays!
Anolis lineatus, Matthijs van den Burg
Anolis polylepis, Anna Thonis
Anolis evermanni, Anna Thonis
Anolis gundlachi, Anna Thonis
Anolis aquaticus, Lindsey Swierk
Anolis aquaticus, Lindsey Swierk
Anolis aquaticus, Lindsey Swierk
Anolis marmoratus, Kristin Winchell
Anolis princeps, Jhan Salazar
Anolis carolinensis, Delton Howard
Anolis sagrei, Delton Howard
Anolis oculatus, Charles Watson
Anolis roquet. Photo by Gaëll.
Read all about it in the latest issue of IRCF Reptiles & Amphibians.
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!
Flicker is the bimonthly publication of the Cayman Islands Department of the Environment. The October issue, available here, reports on the introduction of the green anole, Anolis carolinensis, to Grand Cayman, and on continuing efforts to remove green iguanas from that same island. Older issues are also available. If you’d like to receive future issues, contact the editor.
Aryeh Miller and Ansley Petherick
The Finalists Are In!
Thanks to all who submitted photos for the Anole Annals calendar contest–we received lots of great submissions! We’ve narrowed it down to the top 32, and now it’s time for you to vote! Here’s a slideshow of the finalists:
Vote Now!
Choose your 6 favorites in the poll below. You can right-click on the thumbnail to view full-size images in the poll, check the box next to your picks. You have 13 days to vote – poll closes on 12/13/20 (a Sunday) at 11:59pm. Spread the word!
Photo by Rachel Easton.
Periodically, we here at Anole Annals get reports of mating between green and brown anoles. Usually, it turns out to be a case of misidentification–often the “brown” anole is really a green anole in brown color phase, but sometimes it actually does happen. The most recent report comes from reader Rachel Easton, who tells the story of the picture above: “I’ve had them for a few weeks but they lived together at the pet store for months before I had them. They are in a 20 gallon in my greenhouse. This is the first time I’ve witnessed the mating behavior. I moved their tank to another location and about 3 minutes later they were mating. I occasionally see them displaying their throats at one another but I assumed it was a territorial dispute over the best basking spot.”
Photo by Steven Kurniawidjaja, iNaturalist
Hello! Hope you had a good Thursday!
I moved #DidYouAnole and shortened it for this week because of the holiday. We aren’t talking about one specific anole (or lizard) today, but just ideas on an observed behaviour.
Recently someone posted a picture of curly-tailed Brown Anole (Anolis sagrei) noting that they had been seeing this recently with the brown anoles in their area.
This intensity of tail curling, while typical of curly-tailed lizards (they’re named for it!), isn’t all too uncommon in anoles. For curly-tailed lizards, their tail curl is possibly used as part of anti-predator behaviour, meaning it helps them distract a predator away from their bodies, or makes them look bigger. Anoles also use their tails in a similar way, waving them during aggressive displays against other males and predators.
Photo by Bill Lucas, iNaturalist
Lizards use their tail in various kinds of signaling and tail curling is one that we have been observing but don’t quite know a lot about yet! Has anyone else observed this or have any ideas about tail curling behaviour?
Female Clouded Anole (Anolis nebulosus), Guerrero by Levi N. Gray.
Male Clouded Anole (Anolis nebulosus), Guerrero by Levi N. Gray.
Ecogeographical rules attempt to simplify ecological and evolutionary processes that shape morphology. In a cool study published this summer in Current Zoology, Anaya-Meraz and Escobedo-Galván (2020) examine the combined effect of Rensch’s Rule and van Valen’s Island Rule in Clouded Anoles. Specifically:
Rensch’s Rule: within lineages, sexual dimorphism decreases in magnitude with increased body size when females are the larger sex but increases in magnitude when males are the larger sex.
The center black line indicates 1:1 male to female size, the top line and bottom lines indicate male- and female-biased size dimorphism, respectively. *Adapted from Piross et al. 2019.
van Valen’s Island Rule: describes the tendency of diminutive and large mainland species to trend toward gigantism or dwarfism on islands, respectively, due to competitive factors.
*Adapted from Lomolino, 2005
In their paper, Anaya-Meraz and Escobedo-Galván ask, how does Clouded Anole (Anolis nebulosus) sexual size dimorphism change when the Island Rule could be in effect?
Using 305 Clouded Anole museum specimens, they found that sexual size dimorphism differs between the mainland and island populations. While all populations revealed variation in the degree of sexual size dimorphism, populations on the Islas Tres Marías uniformly possess male-body size bias. But on the mainland, 40% of the populations had the opposite pattern, female-body size bias.
Intriguingly, Anaya-Meraz and Escobedo-Galván note that in the Clouded Anole, island males spend almost 50% more of their waking period engaged in some form of social interaction (Siliceo-Cantero et al. 2016). This is offered as an explanation for why male Clouded Anoles also have larger dewlaps among the Tres Marías populations.
In lizards, the Island Rule may not necessarily stand out as a trend (Meiri, 2007), but we see from Anaya-Meraz and Escobedo-Galván’s study that male Clouded Anoles are larger on islands. On the Antillean Islands, the magnitude of sexual size and shape dimorphism of anoles decreases with increased anole species diversity (Butler et al., 2007). The Islas Tres Marías populations follow this pattern in having increased sexual size dimorphism when not competing with other anole species.
*Adapted from Poe et al. 2017.
Overall, Clouded Anole body and dewlap sizes are larger in insular populations while Rensch’s Rule does not show a clean pattern in this species. However, as noted by the authors, it is important to consider the adaptive force of being on an island versus the ancestral condition. To truly understand morphological evolution within a species and across the genus we need to know body size trends of closely related species. Moreover, some researchers are discouraging studies that determine the universality of ecogeographical rules in favor of integrative approaches based around hypothesis testing (Lomolino et al. 2006, Lokatis & Jeschke, 2018).
What do you think? Is there room for using ecogeographical rules within an integrative framework (See Benítez-López et al. 2020)? Or do ecogeographical rules obscure true drivers of adaptation?
References:
Anaya-Meraz, Z. A., and A. H. Escobedo-Galván. 2020. Insular effect on sexual size dimorphism in the Clouded Anole Anolis nebulosus: when Rensch meets Van Valen. Current Zoology, doi: 10.1093/cz/zoaa034.
Benítez-López, A., L. Santini, J. Gallego-Zamorano, B. Milá, P. Walkden, M. A. J. Huijbregts, and J. A. Tobias. 2020. The island rule explains consistent patterns of body size evolution across terrestrial vertebrates. bioRxiv 2020.05.25.114835. Cold Spring Harbor Laboratory.
Butler, M. A., S. A. Sawyer, and J. B. Losos. 2007. Sexual dimorphism and adaptive radiation in Anolis lizards. Nature 447:202–205. Nature Publishing Group.
Lokatis, S., and J. M. Jeschke. 2018. The island rule: an assessment of biases and research trends. Journal of Biogeography 45:289–303. Wiley Online Library.
Lomolino, M. V. 2005. Body size evolution in insular vertebrates: generality of the island rule. Journal of Biogeography 32:1683–1699.
Lomolino, M. V., D. F. Sax, B. R. Riddle, and J. H. Brown. 2006. The island rule and a research agenda for studying ecogeographical patterns. Journal of Biogeography 33:1503–1510.
Meiri, S. 2007. Size evolution in island lizards. Global Ecology and Biogeography, 16:702-708.
Poe, S., A. Nieto-montes de Oca, O. Torres-Carvajal, K. De Queiroz, J. A. Velasco, B. Truett, L. N. Gray, M. J. Ryan, G. Köhler, F. Ayala-Varela, and I. Latella. 2017. A Phylogenetic, Biogeographic, and Taxonomic study of all Extant Species of Anolis (Squamata; Iguanidae). Systematic Biology 66:663–697.
Piross, I. S., A. Harnos, and L. Rózsa. 2019. Rensch’s rule in avian lice: contradictory allometric trends for sexual size dimorphism. Scientific Reports 9:7908. Nature Publishing Group.
Siliceo-Cantero, H. H., A. García, R. G. Reynolds, G. Pacheco, and B. C, Lister. 2016). Dimorphism and divergence in island and mainland Anoles. Biological Journal of the Linnean Society, 118:852–872.
This post was originally published on biomh.wordpress.com.