  A generalized seasonally-varying predator-prey model with Allee effect in the
prey growth is investigated. The analysis is performed only on the basis of
some properties determining the shape of the prey growth rate and the trophic
interaction functions. General conditions for coexistence are determined, both
in the case of weak and strong Allee effect. Finally, a modified Leslie-Gower
predator-prey model with Allee effect is investigated. Numerical results
illustrate the qualitative behaviors of the system, in particular the presence
of periodic orbits.
