Effects of Brachypterolus pulicarius (L.) (Coleoptera: Nitidulidae) on Growth and Seed Production of Dalmatian toadflax, Linaria genistifolia ssp. dalmatica (L.) Maire and Petitmengin (Scrophulariaceae)

The impact of the ovary-feeding beetle Brachypterolus pulicarius on the growth and reproduction of Dalmatian toadflax, Linaria genistifolia spp. dalmatica, was evaluated in greenhouse and field experiments. Studies were conducted with paired plants (with and without B. pulicarius) in the greenhouse and field. Plants from three different age groups (3, 6, and 12 months old) were used. Results of both split-plot analysis of variance and path coefficient analysis indicated that B. pulicarius feeding reduced the height of Dalmatian toadflax plants by up to 23 cm; increased the number of primary and secondary branches by 77 and 95%, respectively; reduced the number of flowers produced per plant by 44 to 49%; and decreased seed production by 43 to 93%. Brachypterolus pulicarius affects reproduction allocation, seed production, and dispersal and may reduce the potential for rapid adaptation by Dalmatian toadflax because fewer seeds will limit the chance of successful mutations. Therefore, B. pulicarius may prove to be an important component in the integrated weed management of Dalmatian toadflax.