Joseph A. Sisneros(2007): Saccular potentials of the vocal plainfin
midshipman fish, Porichthys notatus. J. Comp. Physiol. A, 193/4, 413-424.
Abstract: The plainfin midshipman fish, Porichthys notatus, is a vocal
species of teleost fish that generates acoustic signals for intraspecific
communication during social and reproductive behaviors. All adult morphs
(females and males) produce single short duration grunts important for
agonistic encounters, but only nesting males produce trains of grunts and
growls in agonistic contexts and long duration multiharmonic advertisement
calls to attract gravid females for spawning. The midshipman fish uses the
saccule as the main acoustic endorgan for hearing to detect and locate
vocalizing conspecifics. Here, I examined the response properties of evoked
potentials from the midshipman saccule to determine the frequency response
and auditory threshold sensitivity of saccular hair cells to
behaviorally-relevant single tone stimuli. Saccular potentials were recorded
from the rostral, medial and caudal regions of the saccule while sound was
presented by an underwater speaker. Saccular potentials of the midshipman,
like other teleosts, were evoked greatest at a frequency that was twice the
stimulus frequency. Results indicate that midshipman saccular hair cells of
non-reproductive adults had a peak frequency sensitivity that ranged from 75
(lowest frequency tested) to 145 Hz and were best suited to detect the low
frequency components (?105 Hz) of midshipman vocalizations.
S. E. Roian Egnor, Jeanette Graham Wickelgren and Marc D. Hauser
(2007):Tracking silence: adjusting vocal production to avoid acoustic
interference. J. Comp. Physiol. A, 193/4, 477-483.
Abstract: Organisms that use vocal signals to communicate often modulate
their vocalizations to avoid being masked by other sounds in the
environment. Although some environmental noise is continuous, both biotic
and abiotic noise can be intermittent, or even periodic. Interference from
intermittent noise can be avoided if calls are timed to coincide with
periods of silence, a capacity that is unambiguously present in insects,
amphibians, birds, and humans. Surprisingly, we know virtually nothing about
this fundamental capacity in nonhuman primates. Here we show that a New
World monkey, the cotton-top tamarin (Saguinus oedipus), can restrict calls
to periodic silent intervals in loud white noise. In addition, calls
produced during these silent intervals were significantly louder than calls
recorded in silent baseline sessions. Finally, average call duration dropped
across sessions, indicating that experience with temporally patterned noise
caused tamarins to compress their calls. Taken together, these results show
that in the presence of a predictable, intermittent environmental noise,
cotton-top tamarins are able to modify the duration, timing, and amplitude
of their calls to avoid acoustic interference.
Kind regards
Sonja
PS: Please contact the authors for reprint requests.
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University of Vienna, Dept. of Behavioural Biology
Sonja Amoser
PhD Student, Research Associate
Althanstrasse 14
1090 Vienna
Austria
tel: +43 (1) 4277 54467
fax: +43 (1) 4277 54506
mobile: +43 (664) 500 61 06
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