Zidona dufresnei is a volute, not a top shell.  Top shells are
herbivorous, but volutes are predators, feeding on a wide range of
invertebrate animals, including other mollusks.  Probably some volutes
are sufficiently opportunistic to feed on a dead animal they find (and
can thereby be caught in traps), but I don't know specifically if Zidona
dufresnei does this.

Paul M.