Anolis equestris displaying. Photo by Ultra Violet.
We at AA obviously have a soft spot for those monstrously grotesque, yet winningly appealing giants of the anole world. Here’s a lovely picture that just passed through the tweet-o-sphere. Good pictures of knight anoles dewlapping are few and far between, and Ultra Violet kindly allowed us to reproduce it here.
Photo by Frank Burbrink
Ophidiologist extraordinaire Frank Burbrink posted a photo of this Costa Rican anole on Facebook, challenging several of us to identify it. The consensus is that it’s A. lionotus or perhaps A. poecilopus. Any thoughts? More importantly, Frank of snake phylogenetics fame (including a paper on Caribbean serpents), had this to say:
“I really like these streamside anoles. Ecologically and morphologically they seem so un-Anolis like. There were tons of these guys along the wet rocks also inhabited by plethodontids nearby. I would love to see an Anole Annals post about these the very wet streamside anoles.”
So, here one is! He goes on:
“First off…they seemed unusually wet and cold. Second they were everywhere. Third they seemed to be able to hold onto the face of very slippery large rocks (boulders)…some right next to the waterfalls. I am not sure how they actually got there…unless they swam and crawled up the face of the rock. That seems like it wouldn’t take much effort to observe how they do it. Anyhow, everything about them was very non-anole like—other than the huge dewlap, body and head shape.”
Photo by Frank Burbrink
“They seem to exist in a niche not filled by other lizards …certainly not even the semi-aquatic gymnothalmids. It makes you wonder from what ancestral ecomorph they invaded this particular niche…which again seems so un-Anolis” like.
Editor’s note: we’ll be hearing soon about the talks in the upcoming herp meetings, one of which is on aquatic anoles. More on that soon.
A twofer. Photo by Frank Burbrink
Quite a line-up! This August in San Juan. Schedule below, and details on their website, as are the abstracts:
DAY I: August 1, 2013
8:30 Ray Huey Opening remarks
9:00 Ariel Lugo Climate change or land cover change? Which is driving some lizards to the lowlands?
9:30 Jennifer Sunday Global patterns of thermal tolerance and range limits in ectotherms
10:00 Barry Sinervo On the risk of extinction of tropical ectotherms: Are they buffered against climate?
10:30 Coffee Break
11:00 Elvira Cuevas Update of climate change in the Caribbean, and projections on soil nutrient cycling and interactions
11:30 Omar Gutierrez Significant diurnal and seasonal variation in soil CO2 efflux is positively related to temperature in a moist subtropical forest in Puerto Rico
12:00 Lauren Buckley Thermal specialization of ecotherms on tropical mountains
12:30 Michael Kearney The thermodynamic niches of tropical ectotherms
1:00 Lunch Break
2:30 Mike Kaspari Life in the boundary zone–the thermal ecology of small cursorial insects
3:00 Patricia Burrowes Climate change efects on Caribbean seasonality and its implications on an ectotherm host-pathogen dynamics
3:30 Carlos Navas Vulnerability of anuran amphibians to climate change: inferring the impact of water availability and temperature
4:00 Ana C. Carnaval Integrating data sets to validate models of biological response to former climate change in the Brazilian Atlantic forest
4:30 Coffee Break
5:00 Mridul Thomas The effects of ocean warming on marine phytoplankton diversity
5:30 Brad Lister Long-term declines in arthropod abundance restructure a rainforest food web
DAY II: August 2, 2013
8:30 Martha M. Muñoz Evolutionary stasis and lability in thermal physiology in a group of tropical lizards
9:00 Luisa Otero Effects of recent climate warming on the reproductive phenology of Puerto Rican Anolis lizards
9:30 Alexander Gunderson Behavioral responses to thermal variation: implications for predicting the biological impacts of climate change
10:00 Michael L. Logan Population level differences in thermal ecology suggest resilience to warming among Honduran Anolis lizards
10:30 Ignacio de la Riva Thermal ecology of Bolivian lizards of the genus Liolaemus: Will climate warming drive them to extinction?
11:00 Mat Vickers Sunshine, on a cloudy day
11:30 Michael Angilletta Symposium highlights
12:00 Leave for Field Trip to El Verde
Anolis pulchellus with a cool aggressive display. Photo by Manuel Leal.
A few days back, we reported on a recent paper on hybridization between the Puerto Rican grass-bush anoles, A. krugi and A. pulchellus. But what better way to get the backstory than to hear it straight from the horse’s mouth? So, check out co-author Manuel Leal’s description of how the paper came to be over at Chipojolab.
Developing bark anole embryo. Photo by Catherine May.
A while back, Anthony Geneva offered excess A. distichus eggs from their breeding colonies to any researchers would could use them. Some were sent to Kenro Kusumi’s lab at Arizona State, and Catherine May has now published some cool images of embryos at different ages (1-7 days old and 14+ days old).
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!
Liolaemus tenuis, if I’m not mistaken. Photo by Felipe Rabanal.
South American fence lizard lookalikes Liolaemus keep on racking up the species numbers as new taxa are described willy-nilly. Over at Tetzoo, Darren Naish has written a nice post entitled “The enormous lioaemine radiation: paradoxical herbivory, viviparity, evolutionary cul-de-sacs and the impending mass extinction.” It’s a very nice overview of the different aspects of diversity of this clade, including summary of an interesting recent paper by Pincheira-Donoso and colleagues, and includes the chilling statement: “some herpetologists think that the Liolaemus radiation will eventually exceed the Anolis (sensu lato!) one in terms of number of species.”
The just concluded evolution meetings in Snowbird, UT featured many highlights, but surely none more sensational than this fantastic tattoo adorning the arm of Tulane graduate student Justin Yeager. Justin, whose very cool research focuses on poison arrow frogs, bioluminescent millipedes and mantisflies, assures that a space is reserved on his other arm for a lady proboscis, which as we all know is hornless.
Word on the street is that there are some other very cool anole tattoos out there. Photos welcome!
In collaboration with the Conservation Biology course taught by Dr. Karen Beard here at Utah State University, where I am a Ph.D. student, I have been involved in gathering life history data on ~400 species of reptiles that have been introduced outside of their native ranges for an analysis of how life history traits (e.g., diet, fecundity, longevity) interact with other factors to influence the likelihood of successful establishment. Appendix A of Fred Kraus’ 2009 book Alien Reptiles and Amphibians is the source of the species list we are using, and included in this analysis are 26 species of Anolis. This is where you come in.
First, we coded all anoles as (i) sexually-dichromatic, (ii) diurnal, (iii) non-venomous, (iv) oviparous, (v) omnivores that lack (vi) temperature-dependent sex determination and (vii) parthenogenesis. Is anyone aware of any exceptions to these seven generalizations?
Second, we searched for data on clutch size, clutch frequency, incubation time, and longevity. The Anole Classics section of this site and the Biodiversity Heritage Library were particularly useful. After conducting what I feel to be a pretty thorough literature scavenger hunt, I am forced to conclude that some of these data simply do not exist at the species level for all of the species we’re interested in, or are not explicitly stated in a way that is obvious to a non-anole-expert. Of course, there is a lot of literature, including many books that I don’t have access to, and there are also lots of credible observations that don’t get published. I’m hoping that some of the readership here can help fill in at least some of the blanks in the table below. As one member of the team, I did not collect all of the data that are filled in myself, nor have I personally vetted every value, so if you spot an error please do point it out.
Two important points:
Without further ado (for your enjoyment, and because I know from my own blog that nobody reads posts lacking pictures, I’ve embedded an image of each species):
| Species | Median clutch size | Median clutches per year | Incubation time (days) | Maximum longevity (months) |
 A. aeneus |
2 | |||
 A. baleatus |
||||
 A.bimaculatus |
2 | 43 | 84 | |
 A. carolinensis |
1.15 | 6 | 41.5 | 65 |
 A.chlorocyanus |
1 | 18 | ||
 A. conspersus |
1 | |||
 A. cristatellus |
2.5 | 18 | 83 | |
 A. cybotes |
1 | 18 | 45 | |
 A. distichus |
1 | 16 | 45.5 | |
 A. equestris |
1 | 1 | 48 | 149 |
 A. extremus |
||||
 A. ferreus |
1 | 18 | ||
 A. garmani |
1.5 | 18 | 67 | |
 A. grahami |
1 | |||
 A. leachii |
||||
 A. lineatus |
||||
 A. lucius |
1 | 3.5 | 60 | |
 A. marmoratus |
2 | 50 | ||
 A. maynardi |
||||
 A. porcatus |
1 | 18 | 63.5 | |
 A. pulchellus |
1 | |||
 A. richardii |
1 | |||
 A. sagrei |
2 | 20 | 32 | 22 |
 A. stratulus |
||||
 A. trinitatis |
2 | 50 | ||
 A. wattsi |
1 |
Thanks in advance. I think this is a great blog and I hope to post something more interesting on here soon.
Anolis sagrei mating. Image from Bob Cox’s lab website
Although the Evolution meetings are coming to a close, we get to go out on a high note. Christian Cox gave one of the last talks of the day discussing the hormonal basis for gender differences in sexual size dimorphism in anoles. Sexual size dimorphism (SSD), or the tendency for the sexes to differ in the size of different traits, has been widely documented in nature. Usually the male exhibits comparatively larger features, such as bigger body size or larger ornaments. Anoles are an intriguing case of SSD, as the traits that can exhibit dimorphism can vary widely among species. Some species, such as Anolis carolinensis, exhibit SSD in multiple traits, including body size, head shape, and dewlap size. In contrast, other species exhibit minimal SSD. As an example, A. distichus from the Caribbean island of Hispaniola tends to show no SSD in body size or head shape, but has strong SSD in dewlap size.
Christian Cox and his collaborators posit that one mechanism underlying SSD may be a pleiotropic regulator that can couple and decouple dimorphism in different phenotypes and their candidate for this study was testosterone. They conducted experiments manipulating levels of testosterone in adult males and females of Anolis sagrei and assessed how body size, head shape, and dewlap traits changed. Anolis sagrei is a particularly good system for assessing the role of SSD in anoles. Male A. sagrei can be up to 50% larger and three times more massive than females.
To conduct the study, they took three year-old male and female lizards and gave them either testosterone or blank subdermal implants. They maintained lizards under laboratory conditions for two months and then gathered information on morphological dimensions and dewlap characteristics. Under testosterone treatment, males and females grew similarly, whereas males grew faster than females in the control group. This merits restating – they were able to make females grow like males just by applying testosterone! Clearly testosterone has strong effects on male-specific growth patterns.
To determine if testosterone affects metabolism, they measured metabolic rate using stop-flow respirometry. They found that testosterone treatment increased metabolic rate for males and females. Correspondingly, they found that visceral fat bodies were lower in testosterone treated animals, suggesting that increased growth is caused by shunting energy towards growth and away from storage metabolism. They further determined that testosterone treatment increased the size of the humerus and femur, but had no significant effect on jaw length and head width. Because this species exhibits little SSD with respect to head dimensions, perhaps this finding is not surprising, but I would be curious to know whether testosterone influences skull growth in species with SSD in head dimensions, such as A. carolinensis.
Finally, the authors found that testosterone led to increased dewlap size in both males and females. In fact, the dewlaps of testosterone-treated females were comparable in size to those of control males and eroded the sex differences that otherwise existed between them. Testosterone treatment decreased the saturation and brightness in the dewlap, leading the authors to suggest that it accelerates its development, as they posit that this color is representative of the fully developed dewlap in the wild.
Thus, they find strong evidence that testosterone plays a large role in modulating SSD in anoles. In particular, it abolishes differences in growth in various traits except for skull shape. And it can create male-like females as well as forge super-males. It would be interesting to see if, in addition to acquiring a male-like morphology, the females would tend to act like males, as well. Their next step is to conduct testosterone manipulation experiments in A. distichus, a species that has low SSD in body size and head shape, but strong SSD in dewlap size, to determine if the effects of testosterone are repeatable in a system exhibiting a pattern of SSD that is different from A. sagrei.
*****************
Extreme sex differences in the development of body size and sexual signals are mediated by hormonal pleiotropy in a dimorphic lizard. Authors: Cox, Christian L.; Hanninen, Amanda F; Cox, Robert M.
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