Anole Annals

Ken Miyata’s handiwork on display outside David Wake’s office

Recently, a chapter of Ken Miyata’s thesis on the ecology of Ecuadorian anoles was published in the Bulletin of the Museum of Comparative Zoology, along with remembrances of Ken–who died 30 years ago–by Jerry Coyne, Chuck Crumly, Ray Huey, Eric Larson, Greg Mayer, and B Wu.

David Wake knew Ken Miyata, too, and here’s what he had to say: “Ken did an undergraduate honor’s thesis with me in MVZ. He was far ahead of his time — we had no digital database but he wanted to do detailed mapping of some species so he selected Batrachoseps attenuatus and then laboriously went through the large MVZ collection. He made a pin for each locality and on the pin recorded the MVZ catalogue number (or first in a series in the case of multiple specimens). Then he researched the exact locality, often going to field notes. The result is still on the wall outside my office! From time to time someone suggests taking it down, but it has now gained the status of historical document! And it is a constant reminder to me of Ken and his enthusiasms and diligence.”

Anoles Link Spatially Distinct Terrestrial Food Webs – Part 1 Of 2

By Sean Giery

On August 3, 2013

In Introduced Anoles, New Research

LIke all the anoles in our study, a considerable fraction of A. equestris’ diet was derived from the flow of allochthonous resources into its habitat.

A. sagrei, probably the most common vertebrate in Florida perch low on trees making occasional forays to the ground to feed.

The ecological importance of small, terrestrial insectivores such as litter frogs and small geckos is a topic that I’ve been curious about for years. While my dissertation research does not include anything about it, I am still quite curious about how these small, diverse and abundant vertebrates fit into ecosystems. Anoles possess all of the attributes that seem to predispose them to strong interactions and soon after arriving in Miami to begin my Ph.D., I decided to launch a small, side-project using tried-and-true food web tools, stable isotopes and gut content analysis to try to illustrate if and how these small, rather inconspicuous predators might affect ecosystem structure and function. The results of this study were just published online in Functional Ecology.

Basically, we found that anoles couple adjacent food webs by consuming insects that move across habitat boundaries. While food web linkages are a potentially important ecological dynamic and our study yielded some unique findings, there are other bits of information for those more generally interested in anole biology. Therefore, I’ve decided to break this post into two parts. Part 1 deals with our primary findings and contextualizes them within current understanding of food web ecology linkages. It’s sort of a geeky treatment of the subject. Part 2 will illustrate some of the other data that we’ve collected that were not dealt with explicitly in the paper that will be of interest to, I suspect, AA readers.

Bidirectional trophic linkages couple canopy and understory food webs

Sean T. Giery,Nathan P. Lemoine, Caroline M. Hammerschlag-Peyer, Robin N. Abbey-Lee, and Craig A. Layman

1. Cross-system resource flux is a fundamental component of ecological systems. Allochthonous material flows generate trophic linkages between adjacent food webs, thereby affecting community structure and stability in recipient systems.

2. We investigated cross-habitat trophic linkages between canopy and understory food webs in a terrestrial, wooded, ecosystem in South Florida, USA. The focal community consisted of three species of Anolis lizards and their prey. We described interspecific differences among Anolis species in the strength and routing of these cross-habitat flows using stable isotope analysis, stomach content analysis, and habitat use data.

3. All three Anolis species in this study consumed different prey, and occupied vertically distinct arboreal habitats. Despite these differences, carbon isotope and stomach content analysis revealed strong integration with understory and canopy food webs for all Anolis species. Modes of resource flux contributing to the observed cross-habitat trophic linkages included prey movement and the gravity-driven transport of detritus.

4. Our study shows that terrestrial systems are linked by considerable bidirectional cross-system resource flux. Our results also suggest that considering species-specific interactions between predator and prey are necessary to fully understand the diversity of material and energy flows between spatially separated habitats.

The study system was dominated by St. Augustine grass and isolated Ficus trees.

Some basics – The community was composed of four anole species, Anolis sagrei, A. distichus, A. carolinensis*, and A. equestris. The study site was recently featured in AA. Generally, the purpose of the study was to describe variation among species in resource use using stomach contents, habitat use, and stable isotope analysis. But based on some initial observations and a bit of stable isotope data, we had considered that there might be a role for anoles in ecosystems via linking spatially distinct food webs. That is, anole diets might be sourced, in part, by primary production originating outside their respective microhabitats. Basically, we knew that anoles occupy distinct arboreal habitats, but when we examined the stomach contents of each, we found that some prey were from habitats spatially distinct from the ones used by each anole species (e.g., How do terrestrial grasshoppers get inside a canopy giant anole such as A. equestris?),which spawned a more in-depth investigation. Additionally, some initial stable isotope data strongly supported the same interpretation – that is, anole diets might be at least partially derived from allochthonous resources.

Ecological And Population Data On Some Little Known Ecuadorian Anoles

By Jonathan Losos

On August 2, 2013

In New Research

Ken Miyata–naturalist, fly-fisherman, and photographer extraordinaire–died tragically young 30 years ago at the age of 32. Among the many items of unfinished business was his gargantuan thesis, Patterns of Diversity in Tropical Herpetofaunas, 787 pages in length and entirely unpublished. The dissertation ranges far and wide over topics herpetological and ecological–check out the Table of Contents at the bottom of the post. Over the years, Ernest Williams tried to talk a number of scientists into guiding some of the chapters into print, but the task was too large and so it has remained shelf-bound.

Anolis peraccae. Photo by Luke Mahler.

After a recent trip to Ecuador, I happened to be looking at the thesis for other reasons (parts of it were incorporated into the description of A. lyra by Poe et al. in 2009) and came across Chapter 2. This multi-part section includes separate studies on the habitat use of three anole species at the Río Palenque field station (A. chloris, A. festae and A. peraccae) and population biology and dynamics of two other species elsewhere (A. boettiger and A. gemmosus). Miyata argued that little was known of the population biology of South American anoles. Thirty years on, the situation isn’t all that different.

Anolis chloris. Photo by Luke Mahler.

As a result, the data presented by Miyata in 1983 are still very relevant today and deserve wider circulation. And for that reason, we decided to publish a lightly-edited version of parts Chapter 2 in the Bulletin of the Museum of Comparative Zoology, appropriate given that Miyata was a grad student in the Museum (this paper, like all other Bulletins of the MCZ, is available online). In addition, in an online supplementary file, a number of his friends) Jerry Coyne, Chuck Crumly, Ray Huey, Eric Larson, Greg Mayer and B Wu) provide reminiscences of Ken.

The paper ranges widely over matters of anole ecology, behavior, and population biology, providing data on five species for which almost nothing exists in the literature. The paper’s findings are summarized in the abstract:

Anolis festae. Photo by Luke Mahler.

Little is known about the ecology and natural history of South American anoles. This study reports the results of a variety of different studies on several relatively common species of Ecuadorian Anolis. In part I, habitat use and population density are compared among three species of Anolis that occur in sympatry at a number of sites in Ecuador. The three species—A. chloris, A. festae, and A. peraccae—are roughly the same body size. These species perch primarily on tree trunks, and A. chloris perches substantially higher than the other two species, which are similar in perch height. Large differences from one year to the next were observed both in mean perch height and in population densities.

Anolis gemmosus. Photo by Jonathan Losos

In Part II, natural history, growth rates, and population densities are reported for two little known Anolis species, A. bitectus and A. gemmosus. Although the two species are from nearby regions and are similar in microhabitat use, they show more differences than similarities in most aspects of their biology. The species have similar ranges in active body temperatures, but A. bitectus is thermally passive, whereas A. gemmosus appears to thermoregulate. Populations of A. gemmosus tend to remain constant through time, whereas A. bitectus undergoes moderate population fluctuations. Both species exhibit little sexual size dimorphism, but in A. bitectus females are larger, and in A. gemmosus males are larger. Anolis bitectus has a fairly high characteristic growth rate, whereas that of A. gemmosus is quite low.

Evidence Suggests That Cloacas Carry Risk: Venereal Disease and Lizard-Parasite Coevolution

By Bryan Falk

On August 1, 2013

In New Research

Anolis cristatellus wileyae - Does this pair need to worry about Cyrtosomum infections?

Anolis cristatellus wileyae – Does this pair from St. Thomas need to worry about Cyrtosomum infections? Read on.

I wanted to write a few posts about parasites because hey – anoles have some really neat parasites! First up are the nematodes in the genus Cyrtosomum, which have been reported from several anoles and some other lizard taxa like Sceloporus and Cyclura. You might remember Cyrtosomum because C. penneri was the worm that AA-contributor Gerrut Norval and his colleagues used to infer that the Taiwanese population of A. sagrei originated from Florida and not Hawaii, something that wasn’t clear from sagrei molecular data (cool!).

Aside from pinworms (we’ll get to these another day), Cyrtosomum species are probably the most widespread nematode parasites in anoles. They’re really small (difficult to see without magnification), and occur in really large numbers in the lizards’ large intestines (many hosts have worm burdens of 100-200). Until recently, we knew very little about their life history – we knew that they could multiply within a single host individual via infective larvae, but we didn’t know how they moved between host individuals. Several authors (including Norval et al.) noted that Cyrtosomum species are only found in adult lizards, and suggested the possibility that these are sexually transmitted parasites.

Okay, let’s just take a moment… Worms, from sex. Yep.

Gabe Langford and his students tested this hypothesis in C. penneri, and

A Dearth Of Anole Talks At The Ecological Society Of America Meetings

By Jonathan Losos

On July 31, 2013

In All Posts

In contrast to their ubiquity at the evolution meetings [1,2], anoles are barely in attendance at the enormous Ecological Society of America meetings. Last year there were but three (including the famous “Kitty Cam” talk), and this year the dearth is worse, with but a single talk this week in Minneapolis. So, here it is, by Rich Glor and part of the symposium on “Coexistence of Closest Relatives: Synthesis of Ecological and Evolutionary Perspectives”:

Patterns of Anolis lizard coexistence across a complex island landscape

Thursday, August 8, 2013: 3:40 PM

M100EF, Minneapolis Convention Center

Richard E. Glor , Biology, University of Rochester, Rochester, NY

Background/Question/Methods

In species rich adaptive radiations, complex patterns of species coexistence result from speciation and natural selection acting over evolutionary time. In Anolis lizards, similar communities of 4-6 arboreal microhabitat specialists that partition available perches by size and height have evolved independently on each of the four largest Caribbean islands. These well-studied communities of anole ‘ecomorphs,’ however, account for only a fraction of anole species diversity. Most anole diversification has occurred subsequent to microhabitat specialization, resulting in complexes of closely-related species that belong to the same ecomorph but appear to be allopatrically or parapatrically distributed in different macrohabitats. We use integrative analyses that combine thousands of anole species occurrence records from public biodiversity databases, GIS environmental data, molecular phylogenetic and population genetic data, and data on phenotypic variation to test three predictions about anole species co-occurrence across the island of Hispaniola: (1) local communities tend to be comprised of microhabitat specialists that evolve relatively early in anole radiations, (2) closely-related or incipient species tend to be allopatrically or parapatrically distributed in distinct macrohabitats, and (3) habitat filtering in extreme habitats leads to communities in which species that are more closely related to one another than expected by chance.

Results/Conclusions

Our analyses support the prediction that local communities tend to be comprised of phenotypically distinct microhabitat specialists that evolved early in anole radiations and are relatively distantly related. Our analyses also support the prediction that closely-related species tend to be allopatrically or parapatrically distributed in distinct macrohabitats. This result, together with a growing body of molecular population genetic data, suggests that both geographic and ecological processes play an important role in recent anole speciation events, and dictate patterns of co-occurrence in closely related anole species. Finally, we find preliminary support for the importance of habitat filtering by recovering evidence for a latitudinal gradient in the phylogenetic composition of local communities whereby communities at the highest altitudes tend to include more closely-related species than communities at lower altitudes. This pattern is particularly evident in the Cordillera Central, where communities of closely related and ecologically unusual species tend to occur at the highest altitudes.

A $90 Night Light?

By Thomas Sanger

On July 29, 2013

In All Posts

Several years ago I reviewed some lighting options for people interested in hunting anoles at night (Who wouldn’t? Throw that noose away!). At the time I recommended several readily available lights ranging from 300 to 700 lumens, $60 to $500 respectively. Needless to say, most anole enthusiasts were likely priced out of the brightest lights. However, I recently found an option affordable to even our dedicated summer field assistants. A relatively new company to the US, Magicshine, advertises an 1100 lumen light for only $90, the MJ-808U.

Maginshine MJ 808U

Now the first thing we should all do is assume that this is too good to be true. In just a few years our discussion has gone from $500 to $90 for a supposedly superior light. Come on! Online reviews of Magicshine’s products are generally favorable, but mixed. Reviews on mountain bike forums comment on the relatively poor construction and historically bad batteries. Several reviewers have also commented on overheating problems for riders not peddling their hardest.The best part of Magicshine is by far their price. But the last I checked we rarely look for anoles on bikes at night so we will need to take all of this in with some hesitation.

So what about herping? Time will ultimately tell how these lights hold up to our uses. I received my light in the mail earlier this week and have used it twice. To keep my hands free I also purchased the accessory head strap for about $8. I also need to purchase the extension cable as the attached cable between the battery and light is too short to reach my backpack from my head. First impressions, the light is retinal burning bright. I have absolutely no complaints there. I will warn you now, however, that the light gets hot, but has yet to overheat for me. I haven’t fully run down the battery yet either, but it has lasted for over 90 minutes of burn time so far. In summary, my first impressions are as the online reviews suggests, there are both pros and cons to this product, but for $90 why not give it a try. I am cautiously optimistic.

Has anyone else discovered this light yet? If so, please share your reviews with the community.

Biomechanics Shed Light On Differences In Signal Behaviour

By Mattias Hagman

On July 29, 2013

In New Research

Why do closely related species sometimes differ in signalling behaviour, despite apparent similarities in the selection pressures that act on the signal? That question is addressed in a paper in Functional Ecology now available as an early view.

Comparing Anolis species from Jamaica that extend the dewlap rapidly with more slowly extending relatives from Puerto Rico, Ord, Collar and Sanger have modelled the performance of the dewlap and then simulated changes to the system to predict its effects on the speed of the dewlap extension. The predictions are then compared with data on both morphology from cleared and stained specimens and actual dewlap speeds for lizards recorded in the field.

The analyses show that morphological changes have affected the performance of the dewlap display in Jamaican and Puerto Rican anoles differently. Within islands structural changes have led to differences in dewlap speed among species, whereas differences between islands are the result of an increase in muscle contraction velocity present in Jamaican species, but absent in Puerto Rican species.

The study is an excellent example of how investigations into the biomechanics of motion-based visual displays can increase our understanding of differences in signal behaviour.

Anole Display Behavior: Posters At the Animal Behavior Meetings

By Jonathan Losos

On July 28, 2013

In New Research

The 50th annual conference of the Animal Behavior Society kicks off today in Boulder, Colorado. Anole presentations are few: only two posters, which begs the question, why aren’t more behavioral biologists studying anoles? Certainly, their behavior is easily observed and manipulated. And, indeed, some such work is conducted, but not nearly as much as one might expect given the ubiquity of the animals in the southeastern U.S. and throughout the neotropics. And, moreover, the behavioral work that is done is relatively infrequently published in the behavior literature or, apparently, reported at behavior meetings. Behaviorists, you’re missing the boat!

In any case, the sole anole reporter at ABS is Joe Macedonia, who is presenting two posters. The first is a comparison of the behavior of the odd gray-dewlapped green anoles with more ordinary, red-dewlapped populations, and the second is a study using anole robots to determine the relative importance of dewlap color and behavior in species recognition; this study has recently been published and we should be hearing more about it soon.

A Comparison of Headbob Display Structure in Gray-Dewlapped and Red-Dewlapped Anolis carolinensis

JM Macedonia, LE Cherry, DL Clark

Many species of diurnal lizards engage in motion displays, termed ‘pushups’ or ‘headbobs’. In the diverse genus Anolis, headbob display structure typically exhibits substantial interspecific, and in some cases population-level, variation. The green anole (Anolis carolinensis) exhibits a red-dewlapped (RD) form found throughout the southeastern USA, as well as a gray-dewlapped (GD) form that is restricted to southwest Florida. Prior research has shown that RD A. carolinensis produce headbob displays of three basic types (Type A, B, C) that vary primarily in display unit durations. Based on known genetic and physiological differences between the two dewlap color forms, we hypothesized that GD and RD males also would differ in headbob display temporal structure. We quantified 440 displays from 24 GD and 15 RD males, and found some, though not all, display units to differ significantly in duration between the two populations. Our results therefore indicate that stereotyped display behavior can be added to the list of known traits that differ between the gray-dewlapped and red-dewlapped forms of A. carolinensis.

Color and motion display discrimination in Anolis grahami: evidence from responses to lizard robots

JM Macedonia, DL Clark, DJ Kemp

Anolis lizards exhibit color and motion displays that are thought to mediate species recognition, but direct experimental support is limited. We used lizard robots in two field experiments to test the relative importance of dewlap color (calibrated using a computational visual model) and headbob display structure for species recognition in Anolis grahami on Bermuda. Results from experiment 1 revealed equivalent, significant decrements in responsiveness of 102 adult male subjects to color and motion display manipulations, relative to the conspecific robot control. Findings also suggested that dewlap hue, not brightness, was responsible for reduced subject response to non-control dewlap colors. In experiment 2 we presented 93 different A. grahami males with conspecific or heterospecific (Anolis extremus) robots that performed their own, or the other species’, headbob displays. Results revealed species-specific body/dewlap coloration to be more important than headbob display structure for species recognition. Although more work is needed, our findings support the proposition that interspecific variation in color and motion displays provides important cues for species recogntition in anoles.

Central American Green Anoles Mating

By Jonathan Losos

On July 27, 2013

In Anole Photographs

Photo: Cesar Barrio-Amorós/ Doc Frog Photography

Cesar Barrio posted this quadtych on his doc frog facebook page. Taken from his balcony in Ojochal, Puntarenas province, Costa Rica, the photo shows Central American green anoles, A. biporcatus, mating in a cecropia tree. Other than the fact that it is a cool set of images, the photos show the dichromatism in dewlap color displayed by this species, which we’ve discussed previously, and also that the male changed color during the course of mating. I wonder why. It also illustrates that this species exhibits relatively little size dimorphism.

As a bonus, Cesar sent me a photo of the inhabitant of the next tree beyond the cecropia, an A. charlesmyersi strutting his stuff.

Photo: Cesar Barrio-Amorós/ Doc Frog Photography

The Incomplete Guide To The Wildlife Of Saint Martin

By Jonathan Losos

On July 26, 2013

In New Research

Mark Yokoyama’s second edition is now out, and available for download for free. Or, if you want to go old school, hard copies are available for purchase on Amazon.

The 128 page guide covers both the native and introduced fauna of Saint Martin, with more than 500 photographs and considerable treatment of invertebrates as well as vertebrates.

Of course, the most important subject of the book are the anoles, two native and two introduced, each of which gets a page. Mark has published previously on the introduced anoles, A. sagrei and A. cristatellus. Both for the moment are restricted in range–to a resort complex and a cruise ship terminal, respectively. If they expand their ranges–and I’m betting they will–it will be interesting to see how they interact with the native A. gingivinus, as well as each other.

The image below on A. pogus will give you a feel for the book. Certainly a must-have if you’re going to St. Martin, and a nice-to-have even if you aren’t.