Meeting Abstract
P3.61 Tuesday, Jan. 6 Elastic mechanisms as a determinant of anuran jumping performance: do toads bounce? ABBOTT, Emily/M*; ROBERTS, Thomas/J; Brown University; Brown University Emily_Abbott@brown.edu
Anuran jumping performance varies widely among species. Biomechanical studies have proposed that some of the best jumpers use an elastic mechanism to produce power outputs that exceed available muscle capacity. Most studies of jump power have focused on good jumpers, and it is unclear whether species with less spectacular jumping performance also utilize an elastic mechanism. To better understand the underlying determinants of jumping performance, we used a force plate to quantify power output and takeoff time in Osteopilus septentrionalis (Cuban tree frogs), Rana pipiens (Leopard frogs) and Bufo marinus (Cane toads). Maximal jumps elicited from a large number of trials were analyzed. O. septentrionalis jumps were both the fastest and most powerful (takeoff time 0.0680.005 s, peak power 308.755.8 W kg-1 body mass), followed by R. pipiens (0.1120.008 s, 66.619.2 W kg-1), while B. marinus performed the slowest and least powerful jumps (0.1750.03 s, 14.74.3 W kg-1). The power output measured for B. marinus corresponds to less than 100 W kg-1 hindlimb muscle mass (16% body mass), well below the power generating capacity of typical Bufo muscle (>200 W kg-1). Evidence for an elastic mechanism in B. marinus is also absent in the shape of power profiles during jumping. The asymmetric power profile of O. septentrionalis is indicative of elastic energy storage early in the jump, while B. marinus symmetrical and relatively shallow power curve may indicate a jump powered directly by muscle contraction. R. pipiens power profile is intermediate and may reflect an elastic mechanism less effective than that of O. septentrionalis. These results suggest that variation in anuran jumping ability may be explained in part by variation in the effective use of elastic mechanisms. Supported by NSF grant 642428 to TJR.
