Category: New Research Page 57 of 66

Polymorphism in dorsal patterns of female Anolis humilis. Color version of photo in Parmelaere et al., Biol. J. Linn. Soc. (2001), courtesy E. Parmelaere.

The topic of female dorsal pattern polymorphism has been broached several times in Anole Annals posts. Such polymorphism occurs in some species and not others; a comprehensive survey by Paemelaere et al. demonstrated that it was much more common in mainland anoles than in island species, and in some clades more than in others.

But the bigger question is: does dorsal pattern matter to the ladies?

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Thom’s recent post on the upcoming SICB meeting reminded me that I was yet to share the anole research I learned about at the Animal Behavior Meeting this past summer in Bloomington, Indiana. There were just a handful of presentations on herp research during the meeting, and I was excited to see that there were others presenting work on anoles:

Sarah Flanagan presented work from her Honors thesis with Catherine Bevier whereby she used mate choice experiments to test whether female Anolis sagrei prefer males with greater physiological capacities and/or higher quality territories. Sarah’s study showed that females preferred males with depleted liver glycogen (glycogen levels were measured in leg muscle and liver samples after mate choice trials). Females, however, did not show a preference for males in a territory filled with plants over males in bare territories.

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Geographic range of natural and introduced populations of Anolis sagrei. From Angetter et al. (2011).

The Cuban brown anole, Anolis sagrei, is indisputably the most successful of all Caribbean anoles. Not only is it found throughout almost all of Cuba at low elevations, but also everywhere in the Bahamas, on many islands in western Cuba, and even on the coast of Central America. Not surprisingly given its natural colonizing ability, the brown anole is the anole most widely introduced by humans as well, now established not only in Florida, but also on many islands in the Caribbean, as well as Taiwan, Hawaii and, most recently, Costa Rica.

What is surprising is how widely the brown anole has spread in North America. As the map above indicates, invasive populations have moved to areas much farther north than the species’ most northerly outpost in the Bahamas. One would think that Cuban anoles—or even Bahamian ones—would not be adapted to conditions in Georgia because environmental conditions are so different from those in Cuba.

To examine this idea, Angetter et al. conducted a species distribution modeling exercise to compare the environmental conditions that characterize the brown anole’s native range with that of its introduced range.

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Incubating A. sagrei eggs.

Anyone who has incubated reptile eggs knows that moisture is important. Without sufficient moisture, eggs quickly desiccate and shrivel beyond any chance of returning to a healthy, turgid state. Because of this, eggs must experience positive water balance during most of the incubation period for successful embryonic development, and the relative moisture content of the incubation medium can greatly impact how much water is taken up by eggs. In turn, this will affect embryonic metabolism and will have important effects on hatchling size.

Those of us who have incubated thousands of reptile eggs have probably come across the occasional ‘odd ball’ that swells up at a healthy rate, but never hatches, and upon dissection nothing but water and yolk oozes out with no sign of an embryo.

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With the the deadline quickly approaching, the National Science Foundation‘s Doctoral Dissertation Improvement Grant (NSF DDIG) program is on the mind on many graduate student anologists (myself included).  These grants provide significant funding (up to $15,000 this year) to graduate students allowing them to expand upon their existing dissertation research. A large part of my preparation has been reading the successful proposals of other students.  That got me to wondering how many other anole-centric proposals have been funded recently.  Luckily, the NSF has a handy search function for just such a question.

I found 16 funded projects since 1987 coming from the labs of 9 PIs (8 of whom have a single funded student each – the 9th PI and most of his 8 funded students post here often).  In total, students of anole science have been awarded $167,306 with a substantial uptick in the last few years. Here’s hoping this trend continues.  Good luck to all applying this year.