The stability of a one-spike solution to a general class of reaction-diffusion (RD)
system with both regular and anomalous diffusion is analyzed. The method of matched
asymptotic expansions is used to construct a one-spike equilibrium solution and to derive
a nonlocal eigenvalue problem (NLEP) that determines the stability of this solution on an O(1) time-scale. For a particular sub-class of the reaction
kinetics, it is shown that the discrete spectrum of this NLEP is determined in terms of
the roots of certain simple transcendental equations that involve two key parameters
related to the choice of the nonlinear kinetics. From a rigorous analysis of these
transcendental equations by using a winding number approach and explicit calculations,
sufficient conditions are given to predict the occurrence of Hopf bifurcations of the
one-spike solution. Our analysis determines explicitly the number of possible Hopf
bifurcation points as well as providing analytical formulae for them. The analysis is
implemented for the shadow limit of the RD system defined on a finite domain and for a
one-spike solution of the RD system on the infinite line. The theory is illustrated for
two specific RD systems. Finally, in parameter ranges for which the Hopf bifurcation is
unique, it is shown that the effect of sub-diffusion is to delay the onset of the Hopf
bifurcation.