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

Abstract

Advertisement 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 skeletochronolog y 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-signi cant. Age was not signi cantly 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).

Age estimation by skeletochronology and advertisement call variation in the black-spotted pond frog (Rana nigromaculata)

“…Lykens and Forester (1987) first observed that the age of males did not influence any call features in the Spring peeper (Hyla crucifer), and these authors concluded that the females could not identify the older males by advertisement calls. Esteban et al (2002) obtained similar findings for Pelodytes punctatus and suggested that other calling measurements (i.e. call intensity) or maleÁ male competition could influence mate selection by females.…”

Osteological differentiation among Iberian <i>Pelodytes</i> (Anura, Pelodytidae)

“…A general heterochronic process, involving all the features, derives from the fact that P. ibericus has a smaller general adult size than the other species, and has been minimized by the use of natural logarithms. This size reduction probably can be explained in part because P. ibericus attains sexual maturity within one year, while P. punctatus is variable in this respect, with at least some individuals (not all) reaching maturity in the second year (Esteban et al, 2002). The list of characters given in Table 18 does not include several skull elements that do not show significant regressions, and no heterochronic perturbation can be observed, as their shape is not directionally changed during the adult growth trajectory.…”

Efeito da temperatura sobre o canto de advertência de Pleurodema tucumanum (Anura: Leiuperidae)

“…However, given that frogs are ectotherms, it is expected that acoustic properties of their calls will vary with temperature (Duellman and Trueb 1994). Moreover, several authors already have demonstrated the correlation of the temporal parameters of the call with the temperature (e.g., Blair 1958, Zweifel 1959, Gerhardt, 1978, Gayou 1984, Schneider and Sinsch 1992, Schneider et al 1993, Márquez and Bosch 1995, Navas 1996b, Schneider and Sinsch 1999, Esteban et al 2002, Martino and Sinsch 2002, Heyer and Reid 2003, mainly in species with energetic calling (Navas 1996a). Hence, the bioacoustic analyses of anuran calls requires considering temperature, so that this factor does not mask intrinsic differences or generate variations in otherwise similar calls.…”