On the Caribbean island of Tobago, there is an odd snake. Many snakes are well camouflaged to blend in their environments, to surprise a tasty meal and to avoid their own predators. Other snakes are brightly colored to advertise their dangerousness to predators (called aposematic coloration). Coral snakes are an excellent example of aposematic coloration, with conspicuously banded color patterns usually in some combination of red, black and white or yellow (and the deadly venom to back it up).
There are also a host of coral snake mimics that look like coral snakes but are not venomous or only mildly so. These mimics get protection for looking like what they are not. However, the snake on Tobago (Erythrolamprus ocellatus), is neither well camouflaged nor a good mimic of coral snakes. It is red with black blotches (not rings) and virtually no white coloration at all.
Now, Tobago does not have coral snakes (though neighboring Trinidad does) and we hypothesized that E. ocellatus was in the process of evolving away from being a coral snake mimic in their absence.
In summer 2014, Erin Hodson (’15) and I did a field experiment to test this idea. Erin (and her friends and family) laboriously made 480 clay replicas of E. ocellatus and the relevant coral snakes (see below). We then hauled them down to Trinidad and Tobago to set out and see what would attack them. Notable overweight baggage fees were incurred.
The paper describing the results of our work has recently appeared in the pages of the journal Evolutionary Biology. Feel free to look it up and see what we found!
Erin E. Hodson and Richard M. Lehtinen. 2017. Diverse Evidence for the Decline of an Adaptation in a Coral Snake Mimic. Evolutionary Biology 44: 401–410.
As I sit here, an ice storm is on the way that will wreck havoc among all of us endotherms that are active at this latitude in January. Our salamander friends, however, are waiting (happily, I hope) below the frost line, looking for signs of spring. Salamanders are ectotherms and have body temperatures (and corresponding metabolic rates) that are primarily influenced by temperatures in the environment. It might seem like an advantage to have high internal body temperatures year round but when the food runs short and the ice storms come, it makes you appreciate that the salamanders have a pretty good system, too.
Earlier this year, my friend Yeong-Choy Kam and I published a paper based on an experiment I conducted in his lab over ten years ago in Taiwan. Time flies! Previously, there had been anecdotal reports of cannibalism in the tadpoles of Polypedates braueri (a large Taiwanese tree frog, see photo below) but no one had tested whether it occurred under controlled conditions. So, we set up a simple experiment where we varied the level of food and the density of tadpoles, expecting that if cannibalism occurs, it should most likely be observed under low food and high density conditions. We did not observe any cannibalism in any of our experimental treatments, suggesting that cannibalism may not actually occur in this species after all (or at least under the conditions we examined).
This was published in the journal Current Herpetology. Glad to have this out, even though it took ten years!
Lehtinen, R.M. and Y.-C. Kam. 2017. No experimental evidence for cannibalism in tadpoles of a rhacophorid treefrog, Polypedates braueri. Current Herpetology 36: 54–57.
The axolotl (Ambystoma mexicanum) commonly referred to as the “Mexican walking fish” is featured as this month’s salamander of the month. This amphibian is interesting due to its ability to regenerate most body parts. The axolotl has the ability to regrow new body parts even including parts of the brain and spinal cord. If an axolotl lost a foot, it has the ability to quickly grow a new limb in under a month! These salamanders are different from most other salamanders because they live their entire lives underwater. Interest in this species is high as they are critically endangered due to expansion of Mexico City, where they are found. If you would like more information on the Axolotl or salamanders in general, follow the link to http://www.livescience.com/52627-salamanders.html
Recently, several colleagues and I published a new taxonomic paper entitled “Cryptic multicolored lizards in the Polychrus marmoratus Group (Squamata: Sauria: Polychrotidae) and the status of Leiolepis auduboni Hallowell) in the journal Amphibian and Reptile Conservation. This paper re-validates an old name for a species of monkey lizards (genus Polychrus) from Venezuela and Trinidad and Tobago. These colorful lizards are found throughout much of South America but the actual diversity within this group has not yet been carefully studied.
Wooster grad Patrick Brennan (‘13) generated the DNA sequences on which a portion of this work in based for his Independent Study thesis. Other unrecognized species likely exist in this group, so our work is not done. Congrats Patrick!