“Adventures of an Expeditionary Biologist:
A Physio-ethological Approach to Amphibian Communication”
by Peter Narins,
Departments of Integrative Biology and Physiology,
and Ecology & Evolutionary Biology,
Center for the Advanced Study of Behavior, UCLA.
Friday, 19th March 2010: 4.00pm
Lecture Theatre 20
Host: David Bickford
“Animal communication occurs when a signal generated by one individual is transmitted through an appropriate channel and results in a behavioral change in a second individual. We have explored specific morphological, physiological and behavioral adaptations in a wide variety of taxa that appear to have evolved specifically to tailor and sculpt intraspecific communication systems.
In this lecture, I will review some of these adaptational studies in amphibians, including:
(1) Cross-modal integration as the basis for understanding agonistic behavior in territorial dart- poison frogs, Allobates femoralis. We used an electromechanical model frog (robot) to present territorial males with visual and auditory cues separated by experimentally-introduced temporal delays or spatial disparities to probe temporal and spatial integration in this animal. Our results demonstrate both that temporal and spatial integration may be reliably estimated in a freely-behaving animal in its natural habitat, and that we can use aggressive behavior in this species as an index of cross-modal integration in the field.
(2) The second example concerns two distantly related organisms: the concave-eared torrent frog (Odorrana tormota), calling near fast-flowing mountain streams of Anhui Province, Central China, and the endemic Bornean frog, Huia cavitympanum, living in a very similar riverine habitat in Sarawak, Malaysia. In addition to the high-pitched audible components, these species’ calls contain previously unreported ultrasonic harmonics. This extraordinary upward extension into the ultrasonic range of both the harmonic content of the advertisement calls and the frogs’ hearing sensitivity is likely to have coevolved in response to the intense, predominately low- frequency ambient noise from local streams.
These two case studies provide evidence that a physio-ethological approach, determining the physiological mechanisms underlying natural behavior, can be a fruitful avenue for elucidating the selective forces acting on the evolution of animal communication systems.”