Effects of age, size and temperature on the advertisement calls of two Spanish populations of Pelodytes punctatus

Abstract

AbstractAdvertisement calls of males from two Spanish populations of parsley frogs (Pelodytes punctatus) were recorded. Body size (SVL, mass) and calling temperature were measured, and age was determined through skeletochronology of phalanges. Calling males were 2-7 years old in Valencia. In Burgos, males were 1-6 years old and the age structure was highly skewed with more than 50% of the sample of males being 1 year old. The range of body temperatures of calling males was similar in both sites (10-15.1°C in Valencia, and 10-17.5°C in Burgos). Males called with the typical two-note advertisement call A-B, although in Burgos it was common to hear A-only calls. In both populations repetition of the second note was rare. Calls of both populations showed a negative correlation between temporal parameters (note duration, inter-note interval, pulse rate) and body temperature. On the other hand, spectral parameters (dominant frequencies and dominant frequency ranges) were not correlated to temperature and correlation with body size (SVL, mass) was non-significant. Age was not significantly correlated with dominant frequency or with any other measured call parameter. Call frequency in Pelodytes is a poor predictor of male body size and does not convey information on age. Thus, any size-related mating trends could result from non-static calling parameters such as call intensity, or from mechanisms of malemale competition (e.g. chorus attendance).