Category: New Research Page 49 of 66

Kat Wollenberg presented a very interesting analysis of geographic variation in Hispaniolan  A. cybotes, distinguishing effects due to environmental differences, microhabitat use, and genetic relatedness. One particularly novel approach was to compare elevational differences that occur independently in a number of different mountain ranges (the different mountain ranges are the red parts in Hispaniola above).

Here’s the abstract:

Diversification within adaptive radiations: the case of Hispaniolan trunk-ground anoles

The evolutionary processes that produce adaptive radiations are still enigmatic to date, as these are by definition recognized after the radiation has occurred, which makes it difficult to study them as an ongoing process. One way to connect pattern to process is to study the processes driving divergence today among populations of species that belong to an adaptive radiation, and compare the results to patterns observed on deeper level. In this paper, we tested whether evolution is a deterministic process with equal outcomes during different stages of the adaptive radiation of Anolis lizards. On the example of a clade of trunk-ground anoles, we inferred the adaptive basis of spatial variation among contemporary populations, and tested whether axes of phenotypic differentiation among them mirror known axes of diversification at deeper levels of the radiation. Although non-parallel change associated with genetic divergence explains the vast majority of geographic variation, we found phenotypic variation to be adaptive as confirmed by spatial convergence across the landscape, as well as genetically independent habitat-associated morphological variation. Morphological diversification of populations occurs recurrently along both tested axes of diversification previously identified in the anole radiation, but different sets of characters are affected.

Ray Huey and Luisa Otero in front of their poster

Anole Annals has previously had a number of posts on the exciting ongoing project in Puerto Rico examining climate change and thermal biology of anoles. Last night, Luisa Otero presented the results of one aspect of the project, examining the reproductive biology of Anolis cristatellus in a forest and an adjacent (i.e., across the street) open habitat. Previous work by Ray Huey (specifically, his dissertation research in the 1970s) showed that in the open in lowland Puerto Rico, crested anoles are able to thermoregulate and maintain a high and constant body temperature, but in the forest, where good sunspots are scarce, anoles don’t thermoregulate and have lower temperatures.

Luisa’s work confirmed that this pattern has not changed even as Puerto Rico has warmed in recent years–open habitats are still thermally preferable for crested anoles. The exciting new twist is that Luisa examined the reproductive rate of the lizards. Every month of the year, more female anoles are gravid in the open habitat, but this result is particularly striking in the winter, when reproduction slows down in the open, but seems to cease entirely in the forest. Hence, differences in thermal biology do appear to have strong effects on individual fitness and presumably population dynamics, and, at least for now, global warming has not changed the relative suitability of different habitats.

Two posters presented at last night’s session examined how anoles respond to predators. In one, Lisa Cantwell of the University of Tennessee conducted a laboratory study on A. sagrei in which she played different bird calls to see if they would respond differently to predators versus non-predators. And, indeed they do, as the graph on the left shows–compare in particular panels c and d, showing that the behavior exhibited depended on which bird call they heard. The next step in the research, now underway as Lisa’s doctoral research (this started as an undergrad project!), is to take this work into the field to study free-ranging anoles.

Anoles beware–this guy’s as bad as he looks.

The second project was also the result of undergraduate research, this time Chris Peterson, who presented research conducted at the La Selva Biological Research Station in Costa Rica as part of an OTS course. Chris and a colleague presented the ground dwelling Anolis humilis with either one spider, a prey species, or two spiders, both the prey and another spider that actually–horrors–eats anoles. They wanted to see whether they were less likely to attack the prey spider in the presence of the predatory one and whether the size of the prey influenced the decision to attack in the presence of the predator. Results seemed to confirm these predictions: the anoles were more likely to attack in the absence of the predator, and when they did attack, it was usually in the presence of a larger prey spider (when alone, size of the prey did not influence likelihood to go for it).

One final tangent–note that the title of this poster uses the generic name Norops. Rumors are swirling here in Vancouver that a new paper is about to appear and reignite the battle over anole nomenclature with a new proposal to split Anolis into multiple genera. Stay tuned!

It’s all there if you magnify the image!

In recent years, the Central American species A. cupreus has been split into six species. Jenny Gubler, working in Kirsten Nicholson’s lab at Central Michigan, presented a poster on the results of a genetic analysis of variation in this group. Examining mitochondrial DNA, she found support for the monophyly of the entire group and for existence of A. dariense, but that A. villai belongs within that species. Biogeographically, a clear separation is seen between those on the Pacific and Atlantic sides of the continental mountain range chains, and the clade is arrayed from north (basal) to south (highly nested), in support of previous work.

We’re now at the halfway point in the World Congress, and so far its been fabulous. As noted previously, most of the anole action is backloaded into the last two days, especially Monday, which explains in part the radio silence on AA thus far. The other reasons for the lack of reportage are that, first, the meeting has been non-stop, leaving little time for posting and, second, that many of AA’s contributors spent all yesterday afternoon in the inaugural meeting of the Anoline Lizard Specialist Group, discussing anole conservation issues, and thus missed a number of anole talks. We’ll hear more about ALGS later, and hopefully other WCH attendees will jump into the void and tell us what we missed yesterday.

Your intrepid correspondent did sneak out of the ALGS meeting to catch one talk yesterday. Joe-Felix Bienentreu of the Senckenberg Research Institute in Frankfurt reported on his studies of the A. pachypus species complex in Central America. In recent years, the group has been split into five species; Bienentreu focused on variation in pachypus itself, which occurs in Costa Rica and western Panama. Within this range, the species shows considerable variation in dewlap color, with some red, some yellow, and some containing both; in all, five groups were initially identified based on dewlap color. An examination of 40 scale and morphological characters for more than 200 specimens across this range led to grouping the first initial groups into two main groups. Genetic analysis with mitochondrial DNA is partially congruent with these groups, but shows some discrepancies.

The ribbon cutting for WCH7 in Vancouver is hours away, and it promises to be a grand occasion. The best and the brightest of herpetology will be there–a month ago, registration already topped 1600. Needless to say, the highlight of the meeting will be the talks and posters on anoles, 24 in all. In June, Emma Sherratt provided the list, but it’s worth re-posting, with the addition of one newly discovered talk (which didn’t use the words “anole” or “Anolis” in the title, and thus was missed). And, to whet your appetite, we provide links to previous AA posts on some of these talks. Don’t miss all the action, either live in Vancouver, or virtually here in AA‘s pages:

Read More

Brad Lister and Andres Garcia report from Guanica, Puerto Rico:

Most likely, every researcher working in the field with anoles has had the same questions that we’ve wondered about for many years.  How much time do resident species spend in the canopy where they are hidden from our view? What is the home range of males and females? On average, how far do individuals move per day? On days when most of the lizards in a given habitat seem to disappear, where do they go? We tried to answer these and related questions by conducting hundreds of hours of observation on Anolis nebulosus in the Chamela dry forest in Jalisco, Mexico. Anolis nebulosus is very rare in this area and we spent more time finding lizards (2-3 hrs/individual) than actually making observations. Often, after hours of searching, the focal individual would disappear from view within minutes.

Obviously the ability to easily find and track small anoles using radio telemetry would be a major asset in our efforts to understand their behavior and ecology.  Previously, transmitter size limited radio tracking to relatively larger lizards such as Sceloporus, Phrynosoma, and Ameiva. Recently, however, Advanced Telemetry Systems has developed 0.2 and 0.5 gram transmitters that make tracking even 3-4 gram female anoles feasible. We are currently in Puerto Rico continuing with our research on climate change and Anolis ecology, and decided to use the ATS transmitters to track A. gundlachi, A. cooki, and A. cristatellus.

The photo to the left illustrates the ATS equipment we are using in the Luquiilo rainforest and the Guanica tropical dry forest.

Read More

What can a kitty cam tell us about the secret lives of anoles? Photo from http://blogs.inlandsocal.com/pets/4501cat.jpg

The 97^th annual meeting of the Ecological Society of America begins Sunday in Portland. These meetings are truly enormous, and given the great amount of ecological research, past and present, on anoles, it’s surprising that there are not more anole talks scheduled. Nonetheless, there are three, and they look to be good ones. On Tuesday, Sean Giery will talk about studies on the ecosystem role of anoles in Miami. Basically, by examining stomach contents and measuring stable isotopes, he determined the extent to which terrestrial resources enter arboreal ecosystems. For A. equestris and A. distichus, the route is terrestrial insects walking up trees and being eaten, whereas for A. sagrei, it results from foraging on the ground. Also on Tuesday, Jason Kolbe talks on an experimental study of founder events in the Bahamas. We’ve already reported on this study, but Jason will be providing at least a few snippets of new data from this year’s field season. Finally, on Thursday, Kerrie Anne Lloyd will talk about a study looking at predation rates by domestic cats in Georgia, as determined by placing Kitty Cams on housecats. Turns out that a favorite prey item is, alas, green anoles.

Check out the abstracts for these talks below the fold, and if any AA readers attend the talks, please file a report.

Read More

Photos from Cádiz and Birds report in IRCF Reptiles & Amphibians.

Trunk anoles are the least diverse and most enigmatic of the six replicated anole ecomorph categories (the others are grass-bush, trunk-ground, trunk-crown, twig, and crown giant). Numerous species of trunk anoles belonging to the distichus species group are a dominant component of Hispaniola’s anole fauna, but Cuba has only one very rare trunk anole species and Jamaica and Puerto Rico have no trunk anoles whatsoever.  In the latest IRCF Reptiles & Amphibians: Conservation and Natural History, Cádiz and Bird report the first occurrence of the Cuban trunk anole – A. loysianus – on Isla de Juventud.  This is the first time that this spectacular little anole species has been reported from Cuba’s largest satellite island.

As impressive as their current diversity may be, anoles have a rather pathetic fossil record.  Aside from a smattering of subfossils that are less than a million years old, all we have to work from are a few amber specimens from the Dominican Republic preserved over a narrow temporal window (15-20 mybp).  This lack of fossils is problematic because molecular genetic data suggest that that Anolis may be more than 50 million years old.  The fossil record for anole relatives isn’t much better, with only a handful of well-characterized fossils that are greater than 10 or 20 million years old existing across Iguania.  Although they are relatively uncommon, previous reports of iguanian fossils have occasionally been sloppy about assignment to extant clades.  Daza et al. (2012) have done a remarkable job of clarifying our understanding of fossil iguanians by providing not only a remarkably detailed and nuanced description of a new fossil iguanian from the Late Pliocene, but also by conducting quantitative phylogenetic analyses that place this fossil in a large tree that includes a diverse range of other fossil and extant iguanians.

Read More