The host specificity of insects on plants and the resulting insect assemblages characteristic of certain plants are well documented. The majority of studies relate to phytophagous insects and their specialisation on particular host plants. Less documented, however, is the specificity of predatory insects to plant hosts. Contrasting sets of beetle taxa (phytophagous Chrysomelidae and Curculionoidea, and predatory Coccinellidae) occurring on plants from selected Myrtaceae and Fabaceae were compared. Characteristic assemblages were identified on the host plants. Taxonomically related plants shared similar beetle assemblages. In contrast, taxonomically related beetles did not share similar host-plant preferences. The host specificity of predatory beetles (coccinellids) was as great as that of the phytophagous taxa.