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United States Department of Agriculture

Agricultural Research Service

Title: Intraspecific variation of Melaleuca quinquenervia leaf oils in its naturalized range in FLorida, the Caribbean, and Hawaii

Authors
item Wheeler, Gregory
item Pratt, Paul
item Giblin-Davis, Robin - UNIVERSITY OF FLORIDA
item Ordung, Kelly -

Submitted to: Biochemical Systematics and Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 4, 2007
Publication Date: August 1, 2007
Citation: Wheeler, G.S., Pratt, P.D., Giblin-Davis, R.M., Ordung, K. 2007. Intraspecific variation of Melaleuca quinquenervia leaf oils in its naturalized range in Florida, the Caribbean, and Hawaii. Biochemical Systematics and Ecology. 35(8):489-500.

Interpretive Summary: The invasive species Melaleuca quinquenervia is a weed that threatens the health of the Florida Everglades and adjacent areas. Biological control efforts have resulted in the release of three Australian insect species. One of the biological control agents, the weevil Oxyops vitiosa, grows and reproduces poorly when fed leaves of one type of the weed. To find suitable sites for release for this weevil and locations where nursery sites can be developed for mass production of weevils, we studied the chemical variation in this plant in Florida. For comparison, we also examined the terpenoid variation in naturalized populations of this species in the Caribbean, Hawaii, and Australia. We found that two chemical variants exist in Florida, each dominated by one compound, either E-nerolidol or viridiflorol. At the 28 populations studied in Florida no regional trends in chemotype dominance were found. More than half (16 of 28) the populations were composed of between 34 and 66% of both chemotypes. A similar number of populations was dominated (> 67%) by either the E-nerolidol (8 populations) or the viridiflorol (6 populations) chemotype plants. Additionally, we calculated the total amount of compounds in leaves from each population and found that the levels in plants grown where M. quinquenervia biological control agents are tested for safety were significantly lower compared with those are most other sites. Moreover, the majority of the plants from this location were assigned to the poor nutrient chemotype. Additionally, the levels of total terpenoids in leaves from plants grown in Australia and the Caribbean were significantly greater than those in leaves from Florida and Hawaii. These results identified 8 populations that would be most suitable for initial releases and where field nurseries could be established for on site mass production of biological control agents.

Technical Abstract: The invasive species Melaleuca quinquenervia is a weed that threatens the biodiversity of the Florida Everglades and adjacent areas. Biological control efforts have resulted in the release of three Australian insect species. Not all populations of the plant however, are equally nutritious to the biological control agent, Oxyops vitiosa (Coleoptera: Curculionidae). Previous results indicated that O. vitiosa had reduced larval survival, growth, and fecundity when fed different M. quinquenervia chemical variants. To find suitable sites for release for this herbivore species and locations where nursery sites can be developed for mass production of weevils, we studied the natural terpenoid variation in this plant throughout its range in Florida. For comparison, we also examined the terpenoid variation in naturalized populations in the Caribbean, Hawaii, and Australia. We found that two chemical variants or chemotypes exist in Florida, each dominated by one sesquiterpene, either E-nerolidol or viridiflorol. At the 28 populations studied in Florida no regional trends in chemotype dominance were found. More than half (16 of 28) the populations were composed of between 34 and 66% of both chemotypes. A similar number of populations was dominated (> 67%) by either the E-nerolidol (8 populations) or the viridiflorol (6 populations) chemotype plants. Additionally, the total amount of terpenoids in leaves from plants grown where M. quinquenervia biological control agents are tested was significantly reduced compared with most other sites. Additionally, the total amount of terpenoids in leaves from plants grown in Australia and the Caribbean were significantly greater than those in leaves from Florida and Hawaii. These results identified 8 populations that would be most suitable for initial releases and where field nurseries could be established for on site mass production.

Last Modified: 12/27/2014
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