Model general overview
We modeled the eco-evolutionary trajectories of parasites influenced by
their host evolutionary history and host-switching events. Thus, we
assumed that the evolutionary history of the host can represent a proxy
for the resources for parasite species (Agosta et al. 2010; Imrie et al.
2021). We also assumed that the probability of host-switching decreases
as the phylogenetic distance between the species of host involved in the
event (original and new host species) increases. Finally, the model
assumes that parasite evolution occurs at the same evolutionary time
scale as the host, which increases possibilities for host-switching as
host speciation occurs. Parasite individuals are explicitly modeled and
characterized by their used host species and genetic identity, following
the description of the model proposed by Higgs & Derrida (1991) and
Manzo & Peliti (1994). This approach allows us to model parasite
speciation. The host species are modeled as resources that impose a
carrying capacity to parasite species, analogous to islands in the
Manzo-Pelit model (Manzo & Peliti 1994), but in the present model, the
islands (hosts species in our case) emerge (as a new host species that
speciate) and the distance between them varies over time, according to a
predetermined time host diversification (i.e. based on ultrametric
empirical phylogenies). The model does not consider the selection
pressure imposed by parasites on the evolution of the resource.
Therefore, we are not modeling a process of reciprocal evolution, or
co-evolution.