photo: Crotaphytus collaris auriceps near Moab, Utah by Barney Oldfield
Research
As a researcher I am interested in animal communication, especially animal signals and displays. I conduct research on this topic in the field and in the lab, using observational and experimental methods.
Visual Signals
male and female Crotaphytus dickersonae
In the visual domain I work primarily with color signals, where I ask questions about signal production ("What pigments and reflective structures are responsible for the colors produced?"), signal perception ("How do the colors appear to the animals on which they are displayed?"), signal function ("What information do the colors convey to the intended receivers?), and signal evolution ("How do factors such as habitat illumination and predator vision influence the evolution of the colors?").
electron micrograph of a butterfly scale
I address the above and related questions using a variety of techniques, such as spectrometry, electron microscopy, chromatography, computational visual modeling, experimental 'playbacks', and field observation.
male Anolis sagrei displaying its dewlap
I also conduct research on motion signals in lizards, where I ask questions such as "How do lizard bobbing displays vary among and within related species?", and "Can individuals use bobbing displays to discriminate their own species or population from others?". Together with colleagues I use robotic lizards to determine the sensitivity of subjects to motion and color variation in their displays, and document the details of their responses using digital video recording and image analysis software.
Acoustic Signals
ringtailed lemur troop
Some primate species, like ringtailed lemurs, convey highly specific information in their alarm calls regarding the class of predator that is presenting a threat. Demonstrating this ability requires data both on "production specificity" (i.e., a narrow range of evoking stimuli) and "perception specificity", which usually is accomplished via call playback experiments. Other species, like ruffed lemurs, have been shown to exhibit much less specificity in their alarm calls.
photo of Crotaphytus dickersonae near Bahia Kino, Sonora, Mexico by Will Wells; photo of ringtailed lemurs at the Duke Lemur Center by David Haring.