Temperature influence on escape behaviour in two species of pygmy grasshoppers

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