Different prey strategies of terrestrial and aquatic species in the carnivorous genus Utricularia (Lentibulariaceae)
Seine, Rüdiger Porembski; Balduin, Melanie; Theisen, Inge; Wilbert, Norbert; Barthlott, Wilhelm
published: Aug 5, 2002
Utricularia is the largest genus of carnivorous plants, however, surprisingly little is known about the prey spectrum within the genus. The scarce information available stems from a few aquatic Northern hemisphere species. Of the 214 species of Utricularia, the vast majority grows terrestrial and the only report on their prey is by DARWIN who gained his results from herbarium specimens. An analysis of trap size in aquatic versus terrestrial species shows significantdifferences indicating differing prey spectra. The small trap size of terrestrial species points towards protozoa as possible prey. The experimental assessment validates this expectation; terrestrial Utricularia species attract and catch protozoa (Blepharisma americana) offered as prey. The paper shows for the first time that terrestrial bladderworts, in contrast to aquatic species, are probably specialized to prey upon protozoa. Trapping of protozoa is considered an ancestral character in the Genlisea/Utricularia clade of the Lentibulariaceae.