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Hawaii Ant Group
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While the establishment of any new ant species in Hawaii is considered detrimental, the following species are of particular concern:
The little fire ant is a very serious pest that can attain very high densities, and
like Solenopsis invicta, its powerful sting poses problems for domestic animals, wildlife, agricultural
workers and others who come in contact with it (reviewed in Wetterer and Porter
2003). Not surprisingly, it has also had tremendous impacts on native invertebrate communities
in natural areas (Wetterer and Porter 2003).
The little fire ant was first detected in Hawaii in March of 1999 near Pahoa, Puna district,
Hawaii Island. It could have reached Hawaii Island from
Florida, but a foreign source is also likely. This species is native to portions, if not most, of
South and Central America and occurs in nearly all Neotropical countries and Caribbean
islands. Later in 1999 little fire ants were also descovered on the island of Kauai.
As soon as the little fire ant was detected on Hawaii Island, Hawaii Department of Agriculture developed a little fire ant pest advisory  . The interagency Hawaii Ant Group advocated the view in September
1999 that combating the little fire ant is exceptionally important since it makes an
excellent surrogate for combating the red imported fire ant. HDOA efforts have involved
detection, experimental efforts at eradication of local populations, and inter-island quarantine.
To date, eradication programs have met with mixed success and the distribution of little fire ants in East Hawaii has continued to expand. The Kauai population was thought to have been eradicated after a series of treatments in 1999, but were re-decovered in the same location in 2003. Eradication efforts on both islands are ongoing.
Source: Krushelnycky, Paul D., Lloyd L. Loope, and Neil J. Reimer. 2005. The Ecology, Policy, and Management of Ants in Hawaii. Proc. Hawaiian Entomol. Soc. 37:1-25.
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The South American red imported fire ant, Solenopsis invicta, had been intercepted by Hawaii Department of Agriculture inspectors in 1991. Identified as among "Hawaii's Ten Least Wanted" pests in a 1996 educational
brochure (CGAPS 1996), this notorious species has invaded more than 125 million hectares in the southern U.S. since the 1930s despite a USDA federal quarantine. In 1998, Solenopsis invicta reached California, where it is still sparse (and still subject to an eradication campaign) but likely to invade most of the state within the next few years, a situation that poses an immense threat to Hawaii because of its high volume of trade with California. The red imported fire ant has invaded numerous Caribbean islands (Davis et al. 2001) from Florida in the last 20 years, and it is capable of doing the same in the Pacific unless concerted action is taken. Already it has reached Australia and New Zealand, where eradication campaigns are underway (Queensland Department of Primary Industries and Fisheries 2003; New Zealand Ministry of Agriculture and Forestry 2004), as well as Malaysia (Na and Lee 2001) and Taiwan (Chiu Yu-Tzu 2004).
In the continental U.S., Solenopsis invicta threatens public health and safety, industry, biodiversity, and quality of life. Its aggressive nature and powerful sting have occasionally caused the deaths of people, injury to many people annually, and injury and death of wildlife, livestock, and pets. If Solenopsis invicta becomes established in Hawaii, it is likely to invade most non-rainforest areas, except for the highest-elevation areas on Hawaii's volcanoes. Consequently, it has the strong potential to negatively affect agricultural lands, parks, residential and other private properties, tourist destinations, and native biodiversity in natural areas.
Solenopsis invicta colonies grow rapidly and reach exceptional sizes; individual mature nest mounds may contain up to 200,000 workers, and there can be more than 500 mounds per hectare. Large numbers rapidly swarm onto anything that is unfortunate enough to disturb the colony, and each individual ant can deliver multiple painful stings. Unsuspecting tourists and children are most are risk for being stung. Attracted to electric equipment, the red imported fire ant commonly infests and damages electrical distribution systems, communication systems, air conditioners, well pumps, traffic boxes, and airport runway lights.
Research indicates that Hawaii's temperatures favor Solenopsis invicta, and the ant has the potential to colonize much of the state. If Solenopsis invicta becomes established in Hawaii, extensive use of pesticides to protect the state's residents, wildlife, tourist industry, agriculture, and other industries would almost certainly be employed, as it has in the continental U.S. The stakes are clearly high for Hawaii to prevent establishment of this species, and HDOA reacted quickly to the news of its establishment in California by implementing stringent measures for importation into Hawaii of certain high-risk items in early 1999.
Sources
Barr, Charles L. 2002. Broadcast baits for fire ant control. Texas A&M University, Texas Imported Fire Ant Research and Management Plan, pub. B-6099, 6-02, 16pp.
Drees, Bastiann M., Homer Collins, David F. Williams, and Awinash Bhatkar. 2002. Considerations for planning, implementing and evaluating a spot-eradication program for imported fire ants. Texas A&M University, Fire Ant Plan Fact Sheet #030.
Krushelnycky, Paul D., Lloyd L. Loope, and Neil J. Reimer. 2005. The Ecology, Policy, and Management of Ants in Hawaii. Proc. Hawaiian Entomol. Soc. 37:1-25.
VanGelder, Ellen and Mikhail Korzukhin. 2002. Predicting temperature-dependent range limits for the Red Imported Fire Ant (Solenopsis invicta) in Hawaii. Poster presented at the 2002 annual Hawaii Conservation Conference.
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The Asian arboreal weaver ant (Oecophylla smaragdina [Fab.]) is widely distributed from Asia to Australia, where it occupies a wide range of forest habitats from savanna and monsoon dry forests to more mesic habitats and rain forests (Holldobler and Wilson 1994). A closely related species lives in Africa. Weaver ants use their larvae as spindles to weave nests in the canopy, and their ability to select an optimal environment within the canopy for their nests gives the group a wide tolerance for different forest types. Given the Asian weaver ant's known distribution and preferred environments, it would be able to invade all forested habitats in Hawaii except perhaps the wettest and coldest rain forests.
The ant is a voracious arboreal predator, which can exclude all sensitive animals from its nest tree as well as closely neighboring trees. Colonies can contain 500,000 or more workers and can control a territory of a dozen or more large trees (Holldobler and Wilson 1994). They control the entire tree surface from the ground up and kill virtually all animals found within their territory (Holldobler and Wilson 1994). Native forest birds would be naive to such a competitor and probably would be unable to nest or forage near an active ant nest. Both native invertebrates and several native forest bird species, as well as the endangered tree-roosting native bat, would be severely affected, and the extinction of many currently listed species as well as many currently nonendangered species would be expected if this species established in Hawaii.
The Asian weaver ant is often considered beneficial by farmers, who have lionized the ants and introduced them to their orchards for pest control for centuries (Way and Khoo 1992). The species has been introduced to south Pacific islands for biocontrol of palm pests (Greenslade 1965). However, its effects on either the intended target or potential nontargets have not been recorded. It could be introduced into Hawaii illegally by well-intentioned gardeners returning from Asia. Less likely is the possibility that fertile queens could arrive as stowaways in aircraft or in shipments of cut flowers or other plant material.
The weaver ant's exceptionally complex behavior makes them popular research animals. The related African species is established in entomological laboratories in the continental United States (Holldobler and Wilson 1994) and could be moved to Hawaii. Holldobler and Wilson (1994) describe a method to transport small colonies within hand luggage on aircraft.
Source: Loope, Lloyd L., Francis G. Howarth, Frederick Kraus, and Thane K. Pratt. 2001. Newly emergent and future threats of alien species to Pacific birds and ecosystems. Studies in Avian Biology No. 22:291-304.
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