The mating calls of six forms belonging to four genera Megophrys,Oreloalax,Scutiger and Leptolalax were recorded in Wawu Mountain National Forest Park,Sichuan Province of China,using cassette tape recorder (Aiwa) and Sony tape with an external microphone.All recordings were analyzed with an IBM PC based 'SIGNAL' software analysis system (Engineering Design,USA).The range of analyzed frequency was set as 0-10 kHz.Acoustic analysis shows that the dominant frequency of L.oshanensis,M.minor,M.sp.,S.(S.)chintingensis,O.omeimontis,and O.schmidti is 4521.9,3456.4,2293.8,1076.5,1071.0 and 1849.4 Hz on average respectively;the note duration is 46.2,90.8,99.6,72.2,78.8 and 110.3 millisecond on average respectively;the note interval is 140.4,253.0,681.4,1517.7,461.3 and 619.5 millisecond on average respectively.One-Way ANOVA analysis indicates that there are significant differences among the analyzed six forms on the dominant frequency,the note duration,and the note interval (P<0.01).Multiple comparisons using Least-Significant Difference (LSD) show that the difference of the dominant frequency between S.(S.) chintingensis and O.omeimontis is not significant (P=0.917>0.05);on the note duration,only L.oshanensis is significantly different from M.minor,M.sp.,O.omeimontis and O.schmidti (P<0.01);on the note interval,L.oshanensis is not significantly different from M.minor,the same with M.sp.versus O.schmidti and O.omeimontis versus O.schmidti (P>0.05).Correlation analysis indicates that there are no significant correlation among the three acoustic characters of dominant frequency,note duration and note interval,and two environmental factors of the elevation and air temperature (P>0.05) except that the note interval is significantly linear correlated with the elevation (r=0.943,P=0.005<0.01).In the light of above,it is suggested that acoustic characteristics of calls are useful in distinguishing forms;the change of the note interval with the elevation may be a kind of strategy of reproduction.
