The Natural Host Range of Beetle Species Feeding on Broom, Cytisus scoparius (L.) Link (Fabaceae), in Southwest Europe

The natural host range of beetles feeding on broom ( Cytisus scoparius ) and 14 other species (including six other Cytisus species) in the tribe Genisteae was investigated at 39 sites in Spain , Portugal and France in 1989 and 1992 as part of a biological control programme for broom . Data on host - plant associations were analyzed for 36 phytophagous beetle species from 18 sites , and host records were listed for an additional 58 species . Nine species were apparently restricted to the genus Cytisus : Cryptocephalus octoguttatus, Gonioctena olivacea, Bruchidius lividimanus, B. villosus, Exapion elongatissimum, E. fuscirostre, Lepidapion sp . 1 , Polydrusus confluens and Tychius parallelus. These field records suggest a narrower host - plant range for some beetle species than laboratory host - range tests , and may assist in interpreting host - plant associations reported in the literature . Beetle species with a restricted host - plant range were rarely found on related non - host plants .