Overseas Collections Play Important Role In Controlling Invasive Species

Melaleuca quinquenervia, commonly known as the "Australian broad-leaved paperbark tree," is a serious invasive plant in Florida that has caused extensive environmental and economic damage. In its native country of Australia, melaleuca trees are widely planted. But in Florida, melaleuca is a pest, growing into immense forests and virtually eliminating all other vegetation.

That's why when the Florida melaleuca population needed to be controlled, ARS scientists at ABCL in Brisbane began surveying, collecting and curating the herbivorous insects of melaleuca and adding them to their extensive collection. More than 450 insect species in the collection feed on melaleuca alone. Two of these insects have been successful in curbing melaleuca's spread and a third has successfully established, thanks to the leadership and cooperative effort from the ARS Invasive Plant Research Laboratory (IRPL) in Ft. Lauderdale, Fla., and cooperators.

The insects join tens of thousands of herbivorous and parasitic insects in ABCL's collection that have been professionally preserved for permanent storage. The specimens are often used for genetic characterization and by taxonomists to conduct systematic studies and identify cryptic species -- new species that look identical to those already known.

ABCL's collection also houses samples of targeted weeds such as melaleuca. These samples are used to help characterize and genetically match weeds in the exotic range with specimens from the native range, an essential component in selecting effective, host-specific biocontrol agents.

During the past 24 years, the scientists at ABCL have explored countries throughout Asia to find the most promising biocontrol agents. According to Matt Purcell, entomologist and director of ABCL, a large percentage of the insects they collect are previously unknown to science. Their collections help to increase the knowledge of biodiversity across different habitats and ecosystems in Australia and Southeast Asia.

Similar biocontrol collections are housed at ARS labs in Montpellier, France; Hurlingham, Argentina; and Beijing, China.