Figure 3. Dependence of chemotaxis motion on the adaptation rate.
(A) The chemotaxis drift velocity 
for different exponential gradient 
. Different symbols represent different adaptation rates 
. Note that 
first increases linearly (dashed line) with 
before reaching a saturation velocity at a critical gradient 
,. We can fit 
with: 
, in which 
is the chemotaxis motility constant given by the linear fitting coefficient and the saturation drift velocity is 
. The dependences of 
and 
on 
are shown in (B) and (C) respectively. For the range of 
we studied, we found that 
is roughly independent of 
and 
depends on 
with a simple scaling relation: 
.