We numerically investigate deformations and modes of networks of semiflexible biopolymers as a function of crosslink coordination number $z$ and strength of bending and stretching energies. In equilibrium filaments are under internal stress, and the networks exhibit shear rigidity below the Maxwell isostatic point. In contrast to two-dimensional networks, ours exhibit nonaffine bending-dominated response in all rigid states, including those near the maximum of $z=4$ when bending energies are less than stretching ones.

• Received 13 August 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.088301