  When predicting the fate and consequences of recurring deleterious mutations
in self-fertilising populations most models developed make the assumption that
populations have discrete non-overlapping generations. This makes them
biologically irrelevant when considering perennial species with over-lapping
generations and where mating occurs independently of the age group. Previous
models studying the effect of perennial life-histories on the genetic
properties of populations in the presence of self-fertilisation have done so
considering age-dependent selection and have found that, contrary to empirical
observations, perennial populations should exhibit lower levels of inbreeding
depression. Here we propose a simple deterministic model in continuous time
with selection at different fitness traits and feedback between population
fitness and size. We find that a perennial life-history can result in high
levels of inbreeding depression in spite of inbreeding, due to higher
frequencies of heterozygous individuals at the adult stage. We also propose
that there may be demographic advantages for self-fertilisation that are
independent of reproductive success.
