Geographic Variations In Life History Characteristics In Polypedates Megacephalus

In this paper, we explored the difference in age structure, clutch size, egg size, body size, testes mass, sperm size, and the correlation of each other in the Polypedates megacephalus from three different populations（Fanjing mountains : 108°44′E, 27°46′N, 449 m.a.s.l.; Shangzhong: 108°43′E, 26°23′N, 680 m.a.s.l.; Leigong mountains: 108°10′E, 26°22′N, 1300 m.a.s.l.）.Research on age structure indicated that males were composed of 4 age groups and 3 age groups composed in females, and sexual maturity age was 2 years old max age in males were 5, in females were 4 in all populations. There was no significant difference in average age among populations(males: F_2,153=1.106, P=0.334; females: F2,62=0.65, P=0.526), also in age distribution between males and females（Fanjing mountains: t=0.213, P=0.832; Shangzhong: t=-0.985, P=0.329; Leigong mountains: t=0.234, P=0.816）.Studies of body size show that there were significant difference between males and females（mean body size, Fanjing mountains, males: 43.74±0.43 mm, females: 59.30±0.66 mm, t=19.81, P<0.001; Shangzhong, males: 42.77±0.44 mm, females: 57.37±0.99 mm, t=13.55, P<0.001; Leigong mountains, males: 44.13±0.47 mm, females: 58.33±1.15 mm, t=11.44, P<0.001）; but there was no difference in males or females inter-populations(males: F_2,153=1.99, P=0.14; females: F2,62=1.02, P=0.37).Further research indicated that males of three populations had no different in growth rate with Von-Bertalanffy’s growth model analysis, but the growth rate of Fanjing population was significant differ from other two populations. And results show a significant correlation between age and body size(males: F_2,153=26.212, P<0.001; females: F1,62=4.027, P=0.049).Studied on testes mass（mean testes mass, Fanjing mountains: 0.078±0.0098; Shangzhong: 0.066±0.0060; Leigong mountains: 0.091±0.0061）and sperm size show that difference in testes mass among populations were similar when eliminate the influence of body size or not, significant difference between Leigong mountains and Shangzhong（LSD: P<0.01）, and tend to be significant difference between Fanjing mountains and Leigong mountains（LSD: P=0.058）; but there was no significant difference in testes mass between Fanjing mountains and Shangzhong populations（LSD: p =0.631）. In this study, we also found that there was no difference between left and right testes within population（P>0.05）, and there was a positive correlation between body size and testes mass(F_2,79=27.77, P<0.001). Comparative study among three populations show that sperm size in Leigong population was significant longer than other two populations（P<0.001）, but there was no different between Fanjing mountains and Shangzhong（P=0.22）, and the correlation between body size and sperm size tend to be negative, between testes mass and sperm size tend to be independent.Research on variation in clutch size exhibited a significant difference among populations（One-way ANOVA: F2,53 = 106.900, P < 0.001）, and population with high altitude had a greater clutch size, but there was no correlation between clutch size and females body size; also exhibited no differ in egg size among populations（One-way ANOVA: F2,51 = 1.786, P = 0.178）. We also found that there was a negative correlation between egg size and females body size in high population, and no significant relationship between clutch size and egg size（Partial correlation analysis: Leigong: r =-0.083, P = 0.376; Fanjin: r = 0.153, P = 0.272; Shangzhong: r= 0.165, P= 0.270）.