Behavioral Ecology Vol. 13 No. 2: 149-153
© 2002 International Society for Behavioral Ecology
Female preference function related to precedence effect in an amphibian anuran (Alytes cisternasii): tests with non-overlapping calls
a Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain b Centro de Biologia Ambiental, Faculdade de Ciências, Universidade de Lisboa, Bloco C2, Campo Grande, P-1700 Lisboa, Portugal
Address correspondence to J. Bosch. E-mail: bosch{at}mncn.csic.es .
We quantified precedence effect (measured as female preference for the leading calls in an acoustic interaction between two males) with non-overlapping, simulated male calls presented with various phase relationships to female Iberian midwife toads (Alytes cisternasii) in two-speaker phonotaxis playback tests. The resulting information determines the shape of the female preference function for intercall delays. Females preferentially approached leading callers for most tested phase angles. We found a gradation in the degree to which females selected the leader. They tended to exert a strong preference for the leader in 30° test, and at higher phase angles, the overall preference was weaker and graded (the higher the phase angle, the lower the preference). Other parameters of female preference (latency and repeatability) also had a graded relationship with phase angle value. The sharp difference in probability of approach between 30° and 60° is consistent with a mechanism of male calling inhibition immediately after hearing a competitor's call previously described in other taxa. In natural interactions, male A. cisternasii adjust the timing of their calls to a phase angle that provides a slight but significant advantage to the leading caller.
Key words: Alytes cisternasii, anurans, calling, female preference, midwife toads, precedence effect.