Abstract: To explore the effects of temperature on tadpole metamorphosis duration and immune function, we measured the metamorphosis duration of tadpoles ofPelophylax nigromaculatus at Gonser stage 37 under water temperature of 21, 23, 25, and 27 ℃, and compared the variations of response to phytohemagglutinin P (PHA-P) at metamorphosis completion period among different water temperature treatments. The results showed that there was no significant difference in body mass, snout-vent length, and ratio of body mass to snout-vent length among different water temperature treatments (P>0.05). The metamorphosis duration was significantly higher in 21  and 23 ℃ treatments than in 25  and 27 ℃ treatments (P<0.05). The responsiveness to PHA-P all peaked at 3 h after injection for all temperature treatments, with an increasing tendency from 21 ℃ group to 27 ℃ group. There was no significant difference for the maximal PHA-P values (P>0.05). The responsiveness to PHA-P was significantly higher at 3 h after injection than at 0, 9 and 12 h after injection under 21 ℃ treatment (P<0.05), but was significantly higher at 3 h after injection than at 0 and 12 h under 23 ℃ treatment (P<0.05). Under 25  and 27 ℃ treatments, the responsiveness to PHA-P was significantly higher at 3  and 6 h after injection than at 0 h. Increasing temperature greatly shortened the metamorphosis duration of tadpoles of P. nigromaculatus. There was an enhanced tendency for the responsiveness to PHA-P, but no forward or delayed responsiveness to PHA-P was observed. Our results indicate that moderately elevated temperature would not reduce cell-mediated immunity during development of tadpoles.

Key words: tadpole, water temperature, phytohemagglutinin-P, development.