Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 2005
Publication Date: November 13, 2005
Citation: Wheeler, G.S. 2005. Chemotype variation of the weed melaleuca quinquenervia influences the biomass and fecundity of the biological control agent oxyops vitiosa. Biological Control. 36:121-128. Interpretive Summary: The invasive species Melaleuca quinquenervia is an invasive weed that threatens the Florida Everglades. The defensive chemicals in the leaves of Melaleuca can limit the effect of biological control agents. Two distinct types of Melaleuca occur in Florida that differ in the types of defensive chemicals present. However, these two types of Melaleuca could not be separated by genetic analysis. A biological control agent the beetle Oxyops vitiosa feeds on the leaves of Melaleuca. We studied the survival, growth and fecundity of adults fed each chemical type. We found that the adults were bigger and laid more eggs when they fed on a type of Melaleuca that contained high concentrations of the chemical E-nerolidol compared with adults fed a type of Melaleuca that contained high concentrations of the chemical viridiflorol. These results indicate that better biological control will occur on E-nerolidol plants and to produce weevils for biological control they should be fed leaves of the plants that contain high concentrations of E-nerolidol.
Technical Abstract: Host plant variability can have a significant effect on herbivore populations by influencing survival, performance and fecundity. We examined the effect of terpenoid variation in two chemotypes of Melaleuca quinquenervia on the fecundity of the biological control agent Oxyops vitiosa (Coleoptera: Curculionidae). The M. quinquenervia chemotypes were distinguished by the principal terpenoids E-nerolidol and viridiflorol. Molecular analysis using both Amplified Fragment Length Polymorphisms (AFLP) and nuclear ribosomal DNA internal transcribed spacer (ITS) indicated that the two chemotypes are not from distinct evolutionary lineages, and either the chemotypes are not under strong genetic control or the molecular markers used are not linked with any genetic control of the chemotypes. Adult biomass and fecundity were reduced when the larvae and adults were fed leaves of the E-nerolidol compared with those fed leaves of the viridiflorol chemotype. By rearing the O. vitiosa weevil on the more nutritious chemotype these results assisted in the mass production and establishment of the M. quinquenervia biological control agent.