“…Because of intraspecific competition and different behaviours between juvenile and adult individuals ( [5,17,22] and references therein), the host population is split into juvenile (J) and adult (A) subpopulations. Let J (t, x, a) and A(t, x, a) be their respective densities at time t, position x ∈ , ⊂ R n , n ≥ 1, and chronological age a ∈ (0, a † ) for juveniles and a ∈ (a 1 , a † ) for adults, with a 1 > 0 [16,26,28].…”