  In this paper, we study the interplay between individual behaviors and
epidemic spreading in a dynamical network. We distribute agents on a
square-shaped region with periodic boundary conditions. Every agent is regarded
as a node of the network and a wireless link is established between two agents
if their geographical distance is less than a certain radius. At each time,
every agent assesses the epidemic situation and make decisions on whether it
should stay in or leave its current place. An agent will leave its current
place with a speed if the number of infected neighbors reaches or exceeds a
critical value $E$. Owing to the movement of agents, the network's structure is
dynamical. Interestingly, we find that there exists an optimal value of $E$
leading to the maximum epidemic threshold. This means that epidemic spreading
can be effectively controlled by risk-averse migration. Besides, we find that
the epidemic threshold increases as the recovering rate increases, decreases as
the contact radius increases, and is maximized by an optimal moving speed. Our
findings offer a deeper understanding of epidemic spreading in dynamical
networks.
