The proposed research will examine six-legged animals (insects) as first step toward testing whether or not design solutions exist that are general features of legged, terrestrial locomotor systems. Results will be compared with our previous research on eight-legged designs (crabs) and published work on quadrupedal and bipedal mammals. Using newly developed, miniature force-plate the applicant proposes to examine mechanical energy fluctuations and stability. Both aerobic and anaerobic energy cost will be measured using miniature treadmill. The applicant will test whether or not: (1) the use of an inverted pendulum mechanism during walking is a general feature of legged locomotor systems, possibility relating to energy conservation; (2) the use of bouncing mechanisms during high-speed locomotion is a general feature of legged stress; (3) major variations in body form of legged locomotor systems affect mechanical power output which may determine metabolic energy cost; (4) stability is the foremost design criteria in small legged terrestrial locomotor systems independent of body form. The comparison of a 6-legged design with 2-, 4-, and 8-legged animals will provide the foundation for the future investigation of the impact of variation in body form on terrestrial locomotion.//