Temperature influence on escape behaviour in two species of pygmy grasshoppers

I studied changes in the escape capability and tactics of two species of pygmy grasshoppers (Tetrix biupunctata and T. subulata) across a range of four ambient temperatures (15 degrees C, 20 degrees C, 25 degrees C and 30 degrees C). Reaction distance and locomotor performance were associated across temperatures. Grasshoppers allowed a foreign object (a hand-held pencil) to approach more closely before escaping at low than at high temperatures, and jumping performance, mean jump length, increased by 60% when the temperature was increased from 15 degrees C to 30 degrees C. In T. subulata, individuals used their wings more frequently when jumping at high temperatures, and moved 47% farther when flying than when jumping without using their wings (T. bipunctata lacks functional wings). Relative jumping performance of individuals changed across the four different temperatures but did not change for individuals participating in jumping trials on four separate occasions at constant temperature. This demonstrates a lack of habituation or prior experience.