| Contents |
| Recently, the ideal free dispersal strategy has been proven to be
evolutionarily stable in the spatially discrete as well as continuous setting. That
is, at equilibrium a species adopting the strategy is immune against invasion
by any species carrying a di fferent dispersal strategy, other conditions being
held equal. In this talk, we consider a two-species competition model where
one of the species adopts an ideal free dispersal strategy, but is penalized
by a weak Allee eff ect. We will show rigorously in this case that the ideal
free disperser is invasible by a range of non-ideal free strategies, illustrating
the trade-o ff between the advantage of being an ideal free disperser and the
setback caused by the weak Allee eff ect. Moreover, a sharp integral criterion
is given to determine the stability/instability of one of the semi-trivial steady
state, which is always linearly neutrally stable due to the degeneracy caused
by the weak Allee e ffect. |
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