Year: 2012 Page 15 of 47

Here on the Anole Annals we like to talk food. Although anoles are predominantly insectivorous creatures, we have documented some of their stranger eating habits on this blog. For example, through recent research we have learned that they are more frugivorous than previously thought. They also include other vertebrates into their diets, such as frogs. Chamaeleolis anoles, we have learned, have specialized molars to aid in crunching mollusks.

Sadly, however, anoles are often also on the receiving side of predation. Anoles are important prey items for many different animals. Sometimes, even plants get their fill on anoles.

In her recently published undergraduate thesis, Dr. Yudisleidy López Ricardo from the University of La Habana, Cuba discusses the diet of the barn owl (Tyto alba furcata) in several localities in Villa Clara and Ciego de Ávila. Dr. López Ricardo examined nearly 300 owl pellets (regurgitated bits that contain food remains) and found 69 different prey types. As expected, small mammals such as the house mouse and black rat were common prey items. A novel finding of this study, however, is that large species of anoles, namely A. equestris, A. porcatus, and even Chamaeleolis sp. lizards were found in the owl pellets. Smaller anoles, including A. jubar, A. sagrei, and A. lucius were also found in the diets of the barn owl. The authors also found that a different herp, the Cuban tree frog, Osteopilus septentrionalis, was not uncommonly found in owl pellets, but this species is nocturnal.

The finding that anoles are a small, but important, component of this species’ diet is quite interesting in light of the fact that Tyto alba, like most owls, is nocturnal. The main question for me is how they are finding and catching anoles. Owls rely heavily on sensitive hearing to locate moving prey at even great distances. But anoles are predominantly diurnal creatures, and are typically asleep and quite still by nightfall. Owls also have great vision and may be spotting anoles during crepuscular hours. Or are they opportunistically feeding on anoles? Perhaps a different predator scares an anole out of its sleeping site and owls are snatching up fleeing anoles.

Any thoughts from the Anolis community on this interesting finding?

Squares are A. gaigei; circles are A. tropidogaster; triangles are locations of members of the species complex for which specimens were not examined and thus determination to species has not yet been accomplished.

Gunther Köhler’s at it again! This time with a merry band of colleagues he’s split Anolis tropidogaster, a little brownjob of an anole widespread in southern Central America and Colombia, into two species, A. tropidogaster in Colombia and eastern Panama and A. gaigei sandwiching it in western panama and the Santa Clara Mountains of Colombia.

Like a number of recently differentiated mainland anoles, the species differ markedly in the shape of their hemipenes. However, in contrast to some other cases, they also differ in dewlap color and a number of scale characters. Further, a limited genetic analysis suggests that the two forms may be substantially differentiated genetically.

The title of the paper says it all: “It is time for a new classification of anoles (Squamata: Dactyloidae).” No doubt, AA contributors will have something to say about this before long, but comments–or posts–are welcome now. The paper–by Nicholson, Crother, Guyer, and Savage–is a 108 page monograph in Zootaxa (text runs to page 69). Anolis is proposed to be split into the following genera: Dactyloa, Deiroptyx, Xiphosurus, Chamaelinorops, Audantia, Anolis, Ctenonotus, and Norops. In addition to presenting a phylogeny and a new classification, the paper also has sections on biogeography, dating, ancestor reconstruction and–most intriguingly–“Evolution of ecomodes in the family Dactyloidae.” Stay tuned!

High school students conducting anole research. Read all about it in the author’s post on the paper.

Everyone knows that anoles, like most reptiles, are not good parents. They just drop off the eggs, and that’s that. If they come across their offspring, they might even eat them! Not a paragon of parenthood. But does that mean the anole moms don’t do anything to help their kids? If nothing else, perhaps they could lay their eggs in places that would lead to maximally healthy offspring.

To test this idea, Aaron Reedy and a cast of dozens conducted an experiment in which they gave female brown anoles a choice of nest substrates varying in moisture content to see if they preferentially put eggs in some places over others. Then, they raised the eggs in the different environments to see if it matters.

The results were clearcut: females prefer to lay eggs in the soil with the highest moisture levels available. And, in turn, it matters: eggs put in such soils (the placement of eggs was randomized after the females laid them) had high hatching success, produced large offspring, and led to an overall increase in offspring survival.

These results are interesting and in agreement with a variety of studies on other reptiles. What is particularly notable about this research is that it was conducted in a low-income neighborhood city high school science classroom. The first author, Aaron Reedy, was a science teacher (he’s now in grad school at the University of Virginia), and the project was conducted by him and a large number of his high school students. Now, that’s remarkable! Reedy provides an interesting account of how the experiment came to be and what the students thought of it in a post at Scientific American’s website.

This paper also brought to our attention another paper published earlier this year that had eluded AA‘s notice.

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