The History of Little Fire Ant Wasmannia auropunctata Roger in the Hawaiian Islands: Spread, Control, and Local Eradication

The islands of Hawaii have been the battleground for successive “inva- sion waves” by exotic ants for over a century. The arrival of Pheidole megacephala (Fabricius) (the big headed ant) in the late nineteenth century, was followed in 1939 by Linepithema humile (Mayr) (the Argentine ant) and Anoplolepis gracilipes (fr. Smith), (the longlegged Ant) in 1953. The most recent arrival is the little fire ant (Wasmannia auropunctata Roger) which was first recorded in 1999. This paper chronicles the subsequent spread of W. auropunctata through the Hawaiian archi- pelago. Initially introduced and spread via the import and sale of nursery plants, W. auropunctata is now well-established on the island of Hawaii. Ubiquitous on the windward side of Hawaii island, W. auropunctata are now being transported not only via nursery plants but also via non-agricultural products. The prevention, detection and response to W. auropunctata introductions is addressed by infor- mal and ad hoc partnerships between a number of agencies, each contributing to preventing and reducing spread of this species. The draft Hawaii Inter-Agency Biosecurity Plan recognizes and strengthens these partnerships and will contribute positively to Hawaii’s biosecurity system

Analysis Taking the sting out of Little Fire Ant in Hawaii

In the 1990's, Little Fire Ants (LFAs) found its way to the island of Hawaii, most likely traveling with a shipment of potted plants from Florida. These plants were subsequently sold to consumers along the east coast of the Island, along with Little Fire Ant colonies living in the potting medium. LFA is now thriving and continues to spread. Fifteen years after the initial detection in 1999, LFA has spread to over 4000 locations on the island of Hawaii and has been found in isolated locations on Kauai, Maui, and Oahu Islands. Current efforts are expected to contain the infestations on the other islands but significant additional investment is needed to halt the rapid spread of LFA on the island of Hawaii. Increased management expenditures can suppress infestations; reduce spread between sectors; and decrease long-term management costs, damages, and stings. • An immediate expenditure of $8 million in the next 2-3 years plus follow-up prevention, monitoring, and mitigation treatments will yield$1.210 billion in reduced control costs, $129 million in lowered economic damages, 315 million fewer human sting incidents, and 102 million less pet sting incidents over 10 years. • Over 35 years, the benefits include$5.496 billion in reduced control costs, $538 million less economic damages, 2.161 billion fewer human sting incidents, and 762 million fewer pet sting incidents