Can native predators be used as a stepping stone to reduce prey naivety to novel predators?

Predator naivety negatively affects reintroduction success and this threat
is exacerbated when prey encounters predators with which they have had no
evolutionary experience. While methods have been developed to inculcate
fear into such predator-naïve individuals, none have been uniformly
successful. Exposing ontogenetically- and evolutionary-naïve individuals
firstly to native predators may be an effective stepping stone to improved
responses to evolutionarily novel predators. We focused on greater bilbies
(Macrotis lagotis) and capitalised on a multi-year mammalian recovery
experiment whereby western quolls (Dasyurus geoffroii) were reintroduced
into parts of a large fenced reserve that contained a population of naïve
bilbies. We quantified a suite of antipredator behaviours and measures of
general wariness across quoll-exposed and quoll-naive bilby populations.
We then translocated both quoll-exposed and quoll-naïve individuals into a
large enclosure that contained feral cats (Felis catus) and monitored
several behaviours. We found that bilbies can respond appropriately to
quolls but found only limited support that experience with quolls better
prepared bilbies to respond to cats. Both populations of bilbies rapidly
modified their behaviour in a similar manner following their
reintroduction to a novel environment. These results may have emerged due
to insufficient prior exposure to quolls, inappropriate behavioural tests
or insufficient predation risk during cat exposure. Alternatively, quolls
and cats are only distantly related and may not share sufficient
similarities in their predatory cues or behaviour to support such a
learning transfer. Testing this stepping stone hypothesis with more
closely-related predator species and under higher predation risk would be
informative.