  We examine the hydrodynamic performance of two cilia beating patterns
reconstructed from experimental data. In their respective natural systems, the
two beating patterns correspond to: (A) pumping-specialized cilia, and (B)
swimming-specialized cilia. We compare the performance of these two cilia
beating patterns as a function of the metachronal coordination in the context
of two model systems: the swimming of a ciliated cylinder and the fluid pumping
by a ciliated carpet. Three performance measures are used for this comparison:
(i) average swimming speed/pumping flow rate; (ii) maximum internal moments
generated by the cilia; and (iii) swimming/pumping efficiencies. We found that,
in both models, pattern (B) outperforms pattern (A) in almost all three
measures, including hydrodynamic efficiency. These results challenge the notion
that hydrodynamic efficiency dictates the cilia beating kinematics, and suggest
that other biological functions and constraints play a role in explaining the
wide variety of cilia beating patterns observed in biological systems.
