Vibration Communication in Vertebrates
143
3.10 Polypedates leucomystax- the Common Malaysian Treefrog
Frogs in the family Rhacophoridae, the Old World treefrogs, comprise 186 species
in 10 genera (Duellman and Trueb 1986). One of these genera, Polypedates,
contains 11 species found in Japan, eastern China, and throughout tropical Asia. In
order to characterize the evoked calling responses of one species in this genus, a
series of acoustic playback experiments was carried out with the common
Malaysian treefrog, Polypedates leucomystax, from Peninsular Malaysia, (Narins
et al. 1998).
Relatively few rhacophorid frogs have been so studied, and P. leucomystax has
the potential for providing an excellent neuroethological model of vertebrate
acoustic behavior, because it is widely distributed, highly vocal, relatively
accessible in its natural habitat, and of sufficient head size to facilitate
electrophysiological investigations of natural sound encoding by the auditory
system (Narins et al. 1998). These workers found that one color morph of the
Malaysian treefrog, Polypedates leucomystax, exhibits a rather unusual behavior.
Females living in dense mats of floating vegetation perch conspicuously on a reed
or blade of grass and tap their rear toes rhythmically on the vegetation. This
activity, which persists for several minutes, occurs in the dark and was only
occasionally accompanied by vocalizations. Thus, it is likely that the tapping
functions as a vibrational signal indicating the female's presence to neigh-boring
males. This is the first known example of a vertebrate using vibratory signaling
via a substrate other than the earth.
3.11 Loxodonta africana and Elephas maximus - the African and
Asiatic Elephants
It has been recently shown that elephants produce significant low-frequency,
substrate-borne vibrations during periods of vocalizations and movement
(O'Connell et al. 1997). The substrate vibrations were characterized as vertically
polarized (Rayleigh) waves with a velocity of about 250 ms- 1 • These workers
make the plausible suggestion that seismic vibrations produced concomitantly
with airborne vocalizations could mediate long distance signaling in these
animals. Whether these seismic signals are detected using a form of bone
conduction involving the relative motion of the massive ossicles with respect to
the skull (Reuter et al. 1998), or via sensory mechanoreceptors in the toes or feet
(O'Connell et al. 1999), is an open question for future research.
4 Concluding Remarks
It is becoming clear that seismic communication and sensitivity to whole-body
vibrations are more ubiquitous among the vertebrates than had been previously
143
3.10 Polypedates leucomystax- the Common Malaysian Treefrog
Frogs in the family Rhacophoridae, the Old World treefrogs, comprise 186 species
in 10 genera (Duellman and Trueb 1986). One of these genera, Polypedates,
contains 11 species found in Japan, eastern China, and throughout tropical Asia. In
order to characterize the evoked calling responses of one species in this genus, a
series of acoustic playback experiments was carried out with the common
Malaysian treefrog, Polypedates leucomystax, from Peninsular Malaysia, (Narins
et al. 1998).
Relatively few rhacophorid frogs have been so studied, and P. leucomystax has
the potential for providing an excellent neuroethological model of vertebrate
acoustic behavior, because it is widely distributed, highly vocal, relatively
accessible in its natural habitat, and of sufficient head size to facilitate
electrophysiological investigations of natural sound encoding by the auditory
system (Narins et al. 1998). These workers found that one color morph of the
Malaysian treefrog, Polypedates leucomystax, exhibits a rather unusual behavior.
Females living in dense mats of floating vegetation perch conspicuously on a reed
or blade of grass and tap their rear toes rhythmically on the vegetation. This
activity, which persists for several minutes, occurs in the dark and was only
occasionally accompanied by vocalizations. Thus, it is likely that the tapping
functions as a vibrational signal indicating the female's presence to neigh-boring
males. This is the first known example of a vertebrate using vibratory signaling
via a substrate other than the earth.
3.11 Loxodonta africana and Elephas maximus - the African and
Asiatic Elephants
It has been recently shown that elephants produce significant low-frequency,
substrate-borne vibrations during periods of vocalizations and movement
(O'Connell et al. 1997). The substrate vibrations were characterized as vertically
polarized (Rayleigh) waves with a velocity of about 250 ms- 1 • These workers
make the plausible suggestion that seismic vibrations produced concomitantly
with airborne vocalizations could mediate long distance signaling in these
animals. Whether these seismic signals are detected using a form of bone
conduction involving the relative motion of the massive ossicles with respect to
the skull (Reuter et al. 1998), or via sensory mechanoreceptors in the toes or feet
(O'Connell et al. 1999), is an open question for future research.
4 Concluding Remarks
It is becoming clear that seismic communication and sensitivity to whole-body
vibrations are more ubiquitous among the vertebrates than had been previously