Jc. Nauen et Re. Shadwick, The scaling of acceleratory aquatic locomotion: Body size and tail-flip performance of the California spiny lobster Panulirus interruptus, J EXP BIOL, 202(22), 1999, pp. 3181-3193
Tail-flipping is a crucial escape locomotion of crustaceans which has been
predicted to be limited by increased body mass (M-b). Given isometric growt
h, one may predict that with growth event duration will decrease as M-b(-1/
3), translational distances will increase as M-b(1/3) translational velocit
y will be independent of M-b, translational acceleration will decrease as M
-b(-1/3), angular displacement will be independent of Mb and angular veloci
ty and angular acceleration will decrease as M-b(-1/3) We tested these hypo
theses by examining the scaling of 12 morphological variables, five kinemat
ic variables and six performance variables of tail-flipping by the Californ
ia spiny lobster Panulirus interruptus.
Growth approximated isometry, which validated the use of the proposed scali
ng hypotheses. For animals from 1 to 1000 g Mb, the predicted scaling relat
ionships for tail-flip duration and translational distance and velocity var
iables were supported; however, translational acceleration performance was
much better than predicted. Predictions for rotation and rotational velocit
y variables were not supported, while the rotational acceleration data clos
ely matched the predicted relationship.
The increase in tail-flip duration as predicted suggests that muscle shorte
ning velocity decreases with growth; the sustained acceleration performance
(similar to findings for shrimp and fish fast-starts) suggests that muscle
force output may increase at a greater rate than predicted by isometry, Th
e scaling of rotational acceleration indicates that the torque produced dur
ing the tap-hip scales with a mass exponent greater than 1. Comparison of t
he tail-flip performance of Panulirus interruptus with those of other crust
acean species reveals a wide range in performance by animals of similar bod
y size, which suggests that the abdominal muscle mag show interesting diffe
rences in contractile properties among different species.