Category: New Research Page 52 of 66

Another week brings another nice batch of anole publications from a few previously held meetings. This batch comes from a combined special issue of General and Comparative Endocrinology that features articles from The Inaugural Meeting of the North American Society for Comparative Endocrinology (NASCE) and the 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology (ISAREN) held last July.  The papers from this meeting are now available at the journal’s page at Elsevier ScienceDirect.

Wade (2012) provides a nice review of structure and function of three sexually dimorphic anole features in green anoles (Anolis carolinensis): the forebrain, the dewlap neuromuscular system, and the copulatory neuromuscular system.  She also reviews comparative studies across anole species of the dewlap system and provides a detailed discussion of endocrine regulation in green anoles.  Cohen & Wade (2012) investigated “Aromatase and 5 alpha-reductase type 2 mRNA in the green anole forebrain: An investigation of the effects of sex, season and testosterone manipulation.”  Finally, in a non-anole paper about other iguanid lizards Hews et al. (2012) investigate “neuroendocrine correlates of aggression differences in adults of two Sceloporus lizard species.”

 

Of all the anoles great and small, near and far, green and brown, one stands out for its combination of elegance, charm, and mystique. I refer, of course, to the Ecuadorian horned anole, Anolis proboscis, denizen of Andean forests, possessor of an enchanted sword, and all-around lizard of mystery. Now, however, the veil has been lifted, as the first reports on the biology of the previously unknown lizard have just been published in Breviora, a journal of the Museum of Comparative Zoology at Harvard.

The mystery comes in three acts. The first concerned the continued existence of the horned anole. The species was discovered in 1953 and over the next 13 years, another five were found, all male like the first, all from the vicinity of the Ecuadorian town of Mindo. Then, for four decades…nothing. Many feared the species extinct, perhaps a victim of the deforestation that has ravaged so much of the Western side of the Andes. All this changed in 2005 when a group of birdwatchers spied one crossing a road near Mindo (mind you, this is an arboreal lizard—insert your own joke). Anolis proboscis lives!

The photo above made its way onto the internet and to the attention of Steve Poe, an expert on locating hard-to-find anoles, who led a team of American and Ecuadorian scientists back to Mindo in the summer of 2009. Poe’s approach to finding day-active anoles is seemingly perverse: he stays up all night looking for them. The reason is simple: many anole species sleep on narrow twigs or leaves, presumably because approaching predators will produce vibrations on the flimsy perches, alerting the lizards to impending danger. Although this strategy may be effective in avoiding predators that creep, crawl or slither along branches, it’s not so well-suited to avoid detection by flashlight-toting herpetologists, who are attuned to locating the tiny reptiles—which conveniently blanch to a pale color at night—even when they’re roosting 20-30 feet high in the canopy. Poe’s team quickly located a large number of lizards, establishing that the species not only exists, but seems to have a healthy population.

Unbeknownst to Poe, another team of researchers independently had discovered a new horned anole locality. This team, from the Ecuadorian Museum of Science in Quito, located five specimens of the horned anole at two sites 11-13 km northeast of the original collecting locality, slightly extending the known range of the species. Both groups published detailed descriptions of the anatomy of the species—the Ecuadorian group last year and Poe’s team as the first of the Breviora set published today—describing previously unknown variation in horn size and shape, as well as differences in color and patterning both among males and between the sexes.

And, speaking of differences between the sexes, that leads to the resolution of mystery number two. Ever since the species was first described and the initial half dozen specimens collected, lizard enthusiasts have wondered—what about the females? Do they have horns, too? Of course, in the absence of any information on the natural history of the species, it was hard to have an informed opinion. Is the horn used in self defense, in which case the lady lizards could probably use one as well as the guys? Or is it used by males to fight amongst themselves, or even as an ornament used to woo or titillate? Nobody knew, and so it was anybody’s guess whether the females were nasally adorned or not. But now we know the answer. Before I reveal it, take a moment and take a guess: yes or no? When you’re ready, scroll past the lovely photo of another male and see for yourself.

 

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The function and evolution of anole dewlaps have been the focus of studies for decades. As flashy, showy displays of color, it’s no wonder that dewlaps even captured the attention of Darwin. However, most studies to date have focused solely on male dewlaps leaving female dewlaps much neglected (but see Johnson & Wade, 2010 and Vanhooydonck et al., 2009). While the possession of dewlaps is less common in females than males, and female dewlaps are often rather diminutive compared to the male’s, the mere presence of female dewlaps in a good number of species, combined with striking variation in color, pattern and size across the genus, begs the question of what is driving the evolution and maintenance of such female ornamentation?

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As reported previously at Anole Annals, The 2012 meeting of the Society of Integrative and Comparative Biologists (SICB) was packed with anoles (1, 2, 3, 4, 5, 6).  At least 17 talks or posters mention Anolis in title (complete list below the fold)!  The abstracts from this meeting are now available via PDF from the Society’s journal Integrative and Comparative Biology.  I was excited to see all of the new anole content as it appeared on Web of Science and other indexes, but disappointed that these titles were only associated with abstracts.  To all of you who presented: please get this stuff published, many of your titles are very compelling and the anole community can’t wait to learn more!

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Have you heard about the extremely expensive (and delicious) coffee from Indonesia made  from beans that have passed through the digestive system of civets (hence called “cat poo” coffee because civets are sometimes called civet cats? Did you know that a similar coffee is produced in Central America, made from beans pooped out by Norops anoles? Well, that’s not what this post is about.

Rather, it’s about several recent studies on anoles in coffee plantations.  One recent study, discussed at further length by Rich Glor, compares the biodiversity of sun and shade coffee plantations in Puerto Rico. The authors note at the outset that biodiversity tends to be higher in shade coffee areas, and wanted to see whether that was true in Puerto Rico. In a truly herculean effort, they censused the lizards, birds, insects and vegetation in six plantations, three shade, three sunny. This was a lot of work. Just for the lizards, they individually marked (via paint spray gun) nearly 5000 anoles.

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It’s immediately clear to anyone visiting the Greater Antilles that humans have had a dramatic impact on natural environments.  Even in those areas that remain forested and seemingly pristine, it isn’t difficult to find the stray coffee bush or mango tree.  Indeed, some understory crops, such as coffee and cacao, have traditionally been grown under an intact canopy.  These traditional practices have been changing over the past few decades, however, as large commercial operations have favored the efficiency of clear-cutting and subsequent cultivation in open sun.  The impacts of this shift from shade to sun cultivation on biodiversity have been debated for decades, with most studies indicating overall losses in biodiversity and super-abundance of a few common species in sun plantations.

In spite of the prevalence of agriculture in the Greater Antilles, relatively few studies have investigated the abundance of anoles and other lizards in different types of agriculturally disturbed habits (but see my first first authored paper!).  A new study by Borkhataria et al. (2012) conducts a comparative analysis of species abundance of birds, anoles, and invertebrates in shade versus sun coffee on Puerto Rico.  This study is a welcome addition to the literature because the portion of coffee on Puerto Rico grown in sun plantations has doubled in recent years, although overall coffee production has declined.

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Few anole species have been responsible for as much taxonomic confusion as the widespread Amazonian species Anolis chrysolepis.  It wasn’t even until 2008 that taxonomists decided once and for all that this species should be called A. chrysolepis (Duméril & Bibron 1837), rather than A. nitens (Wagler 1830) (Mayer 2008 successfully petitioned for recognition of  A. chrysolepis on the grounds that Wagler’s Draconura nitens was a nomen dubium due to the absence of a holotype and an exceptionally vague 4-line description and locality [“America”]).

Largely because of its broad range and remarkable geographic variation in size, shape, and coloration, Anolis chrysolepis has attracted the attention of herpetologists for generations.  

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Elise Knowlton, a graduate student in Manuel Leal’s Lab at Duke University, reports on the initiation of her field research on mating behavior in green anoles in North Carolina

The pug-nosed anole, as it is known, is a pretty weird species. First is its funny-looking face, hence it’s name. Second, it is very unusual among anoles in being relatively large, yet found almost invariably near the ground–most larger anoles are found higher up in the tree. Finally, it’s long legs are ungainly and seemingly awkward. Relatively little is known about its natural history, and there is some indication that in some places, it may have become less common.

Our knowledge of natural history knowledge was expanded ever so slightly by the recent report by Mora et al. in the most recent Herpetological Review of an observation of a male eating a pygmy rain frog (Pristimantis ridens).