To evaluate the effect of thermal acclimation on thermal adaptation and locomotor performance of ant Polyrrhachis vicina Roger, and to test optimality models, the subjects were divided into two groups, acclimated respectively to 15℃ and 13.4～21.6℃ under a 14L∶10D dark-light cycle for 2 weeks. Preferred temperature, critical high temperature, critical low temperature were measured using a thermal gradient apparatus. Pause frequency, sprint speed and maximum length of continuous locomotion were selected as the locomotor parameters of Polyrhachis vicina Roger. The temperature range selected by the ant acclimated to constant temperature is from 19.2～35.2℃, the highest peak of which is 23.2～27.2℃; the preferred temperature of the subject individuals acclimated to constant temperature is (26.39±0.41)℃. The temperature range selected by the ant acclimated to variable temperature is from 21.2～35.2℃, the highest peak of which is 27.2～31.2℃; the preferred temperature of the subject individuals acclimated to variable temperature is (28.70±0.42)℃. One-way ANOVA showed that the preferred temperature of the ants was significantly influenced by both constant temperature and variable temperature (F1, 50=15.70, p<0.001).Critical high temperature of individuals acclimated to constant temperature is (43.48±0.39)℃, while the critical high temperature (CHT) of individuals acclimated to variable temperature is (41.22±0.35)℃; Critical low temperature (CLT) of individuals acclimated to constant temperature is (4.55±0.26)℃, while the critical low temperature of individuals acclimated to variable temperature is (4.83±0.14)℃. One-way ANOVA showed that there is significant difference between the CHT of the ants acclimated to constant temperature and the CHT of the ants acclimated to variable temperature (F1, 22=17.40, p<0.01). There is significant difference between pauce frequency (PF) of individuals acclimated to constant temperature and PF of individuals acclimated to variable temperature (F1, 15=78.29, p<0.001); There is significant difference between sprint speed (SS) of individuals acclimated to constant temperature and SS of individuals acclimated to variable temperature (F1, 15=53.12, p<0.001); There is significant difference between maximum length of continuous locomotion (MLCL) of individuals acclimated to constant temperature and MLCL of individuals acclimated to variable temperature (F1, 15=155.09, p<0.001).Partial correlation analysis showed that there is significant positive correlation between the SS and MLCL of ants acclimated to constant temperature (r=0.63, df=12, p=0.017) and very significant positive correlation between the SS and MLCL of ants acclimated to variable temperature (r=0.81, df=12, p<0.001).The results that the preferred temperature of the animals acclimated to variable temperature didn’t meet the prediction of optimality models.
It could be concluded that the thermal adaptation and locomotor performance of this species are significantly influenced by thermal acclimation and that the results doesn’t support the optimality models.