idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
It has now been shown for the first time that non-avian reptiles are able to adjust their calls in relation to environmental noise as is known for the complex vocal communication systems of birds and mammals. In Tokays, night active geckos, researchers of the Max Planck Institute for Ornithology in Seewiesen found an increase in the duration of brief call notes in the presence of broadcast noise compared to quiet conditions. The geckos did not adjust the amplitude of their calls, however, under noisy conditions the animals produced more of the louder syllables. This discovery shows that the communication systems of non-avian reptiles are much more complex than previously thought.
The sophisticated vocal communication systems of birds and mammals are characterized by a high degree of plasticity in which signals are individually adjusted in response to changes in the environment. One mechanism of such vocal plasticity is the Lombard effect, in which the call amplitude increases depending on the level of ambient noise. This Lombard effect is often accompanied by an increase in the duration of the call, which further helps to detect the signals in noise.
In non-avian reptiles some species do have vocal communication, like for example the Tokay, a night active gecko from South East Asia. Within his repertoire, especially the loud GECK-O call stands out and led to his scientific name Gekko gecko. The GECK-O call has important functions for the communication of Tokay males to attract females and to repel rival males. This call is often preceded by low-amplitude cackles. For their study, Henrik Brumm and Sue Anne Zollinger of the Max Planck Institute for Ornithology exposed Tokays to noise of about 65 dB(A) which corresponds to the traffic noise of a busy street. They wanted to find out if the Lombard effect could also be found in a reptile. And in fact, the Tokays increased the duration of the GECK-calls by 7 percent and the O-calls by 37 percent compared to the control group in quiet conditions. Therefore, the Tokays, and probably also other vocally-communicating reptiles, are able to adjust their calls depending on the ambient conditions.
However, the researchers could not find a Lombard effect in the calls, as the Tokays did not increase the amplitude of their call syllables in relation to the background noise level. „The study suggests that the Lombard effect evolved independently in birds and mammals“, says Henrik Brumm, first author of the study and research group leader in Seewiesen. However, the Tokays employed another strategy to increase the overall signal-to-noise ratio of their calls: Instead of increasing the amplitude of each call component, they produced more of the loud GECK-O syllables and fewer of the softer cackle calls in noise. „We think that the fact that signals will reach the intended recipient is a driving force for the evolution of a communication system, independently of the animal group“, says Sue Anne Zollinger, co-author of the study.
Contact:
Dr. Henrik Brumm
Max Planck Institute for Ornithology, Seewiesen
Research Group Leader „Communication and Social Behaviour”
Phone.: +49 8157 932 355
E-Mail: brumm@orn.mpg.de
Phenotypic plasticity of Tokay calls reveals the complex communication of lizards
Frank Lehmann / Max Planck Institute for Ornithology
None
Korrektur Copyright für das Foto: Henrik Brumm
Merkmale dieser Pressemitteilung:
Journalisten
Biologie
überregional
Forschungsergebnisse
Englisch
Phenotypic plasticity of Tokay calls reveals the complex communication of lizards
Frank Lehmann / Max Planck Institute for Ornithology
None
Sie können Suchbegriffe mit und, oder und / oder nicht verknüpfen, z. B. Philo nicht logie.
Verknüpfungen können Sie mit Klammern voneinander trennen, z. B. (Philo nicht logie) oder (Psycho und logie).
Zusammenhängende Worte werden als Wortgruppe gesucht, wenn Sie sie in Anführungsstriche setzen, z. B. „Bundesrepublik Deutschland“.
Die Erweiterte Suche können Sie auch nutzen, ohne Suchbegriffe einzugeben. Sie orientiert sich dann an den Kriterien, die Sie ausgewählt haben (z. B. nach dem Land oder dem Sachgebiet).
Haben Sie in einer Kategorie kein Kriterium ausgewählt, wird die gesamte Kategorie durchsucht (z.B. alle Sachgebiete oder alle Länder).
