Body size and calling variation in the green toad (Bufo viridis)

Green toads from Sardinia are on average 30% longer and twice as heavy as t hose from the Italian Peninsula. The skeletochronological analysis of an is land and a mainland population showed that differences of size were not a c onsequence of a longer lifespan of island toads, but of their higher growth rate in the pre-adult stages of life. The effects of these differences of size on the acoustic communication system of the species were analysed. Sig nificant differences were observed in both spectral and temporal properties of the calls. The longer size of insular toads resulted in a reduction of 0.24 kHz of the fundamental frequency. Differences of temporal properties w ere mostly due to the different thermal conditions of calling males: with r espect to mainland toads, island green toads were generally active at lower water temperatures and, at the same water temperature, they had proportion ally lower body temperatures.