Anuran Phonotaxis Experiments: Does the Speaker Affect Accuracy?

• Published in: Journal of herpetology 1991-06, Vol.25 (2), p.231-232
• Main Authors: Patricia R. Y. Backwell, Bishop, Phillip J., Passmore, Neville I.
• Format: Article
• Language: English
• Subjects: Amphibia and reptilia; Amphibians; Animal ethology; Biological and medical sciences; Experimentation; Freshwater; Fundamental and applied biological sciences. Psychology; Hyperolius marmoratus; Loudspeakers; Perceptual localization; Phonotaxis; Psychology. Psychoanalysis. Psychiatry; Reptiles; Snakes; Sound pressure; Tulle netting; Vertebrata; Zoology
• ISSN: 0022-1511; 1937-2418
• DOI: 10.2307/1564659

Studies of phonotactic accuracy in many anurans have shown that the auditory system can guidr a female to a sonic target with extreme accuracy. Although an acoustic cue by itself is sufficient to allow for accurate localization, the experimental procedures employed in the measurement of phonotactic accuracy in the past have ignored several factors present under natural conditions. For example, the presence of a visible speaker in an otherwise barren arena may affect localization accuracy of females. Similarly, if a female is close to a sound source, acoustic near-field effects may act as tactile cues. Hyperolius marmoratus is a small anuran with an interaural distance of approximately 8 mm. Female behavior in phonotaxis experiments and in the field suggests the extensive involvement of vision in the localization of mates. We investigated the possible effect of the loudspeaker as a visual cue in aiding localization by using two-dimensional phonotaxis experiments in which approach accuracy was measured when the speaker was visible and when it was concealed from the approaching female. Female accuracy was also measured at different stages of the approach: over the first meter of the approach from the release point; over the last 0.5 m of the approach; and in the final 4 jumps made by the female.