earticle

영어

Predation risk is one of the important forces that driving the evolution of prey behavior. Effectively avoiding predators can increase the survival rate and fitness of prey itself, which is also beneficial when an alien species invading into a new environment. In South Korea, bullfrog is an invasive anuran, we conducted experiments on bullfrog tadpoles to evaluate the functions and behavioral adjusting capability of micro-habitat preference. In first experiment, survival rate of tadpoles was highest in submerged vegetation (75.0%, n=20), which was significantly higher than that in the micro-habitat without vegetation (45%, n=20), and the survival rate in emerged vegetation was 50% (n=20), which did not significantly differ from other two treatments. Results shows that submerged vegetation functions as a shelter that reducing predation risks. In second experiment, most of tadpoles preferred staying longer (77.50±29.26% of observation) in submerged vegetation, which was higher than expectation of 50% (t19=4.20,p<0.001). This frequency that tadpole stay in emerged vegetation treatment was 59.17±21.10%, which did not differ from expectation (t19=1.94,p=0.067).The frequency that tadpole staying in submerged vegetation was higher than that in emerged vegetation(t38=-2.27,p=0.029).This results indicated that bullfrog tadpoles tend to stay in vegetation, especially the submerged vegetation. In last experiment, we repeated second experiment by using wounded tadpoles. Tadpoles stay in submerged vegetation increased to 84.58±22.99%, but it did not increase significantly (t38=-0.85,p=0.400) than previous results. The frequency that tadpole stay in emerged vegetation was 77.5±17.54%, which was higher than that in second experiment (t38=-2.99,p=0.005). Results in third experiment indicating that bullfrog tadpoles have the ability to adjust the avoidance behavior according to previous experiences. In summary, bullfrog tadpoles tend to stay in submerged vegetation which functions as a predation-free refuge, and adjust their anti-predation behavior depending on conditions.