DO INTRODUCED PARASITOIDS DISPLACE NATIVE ONES

An attempt was made to determine from the literature and from experience whether native parasitoids of native pests are eliminated by introduced parasitoids. Several native or previously-introduced parasitoids of exotic pest species have become scarce or apparently have disappeared completely following the introduction of additional natural enemies. It is concluded that native parasitoids can be displaced over much of their range, but there usually are favorable habitats where they are able to co-exist with the introduced species.