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Worldwide, there are close to 10,000 species of ants. Of these, 147 have moved into areas where they are not native. However, of these, only about 40 are said to be tramps, a quaint but often imprecise word used to describe ants which tend to travel with human activities, unnoticed amidst building supplies, plants, packing, heavy equipment and machinery. Within this group, there is a handful of species that may be some of the most damaging of all non-native species to invade the Pacific!
In the Marshalls Islands, only about two dozen ant species of any sort have been recorded. If there are any natives among them, it may be just the "kallep" (trap-jaw ant, Odontomachus simillinus) - but of course, it may have also arrived in prehistoric times. "Kinal" (fire ant, Solenopsis geminata) hails from the tropical Americas. But "kallep buroro" (long-legged ant, Anoplolepis gracilipes) and the very tiny little ant that is sometimes called "kinal edrik" (Monomorium destructor), seem to have come from Africa. Of the general "Ion," the black crazy ant (Paratrechina longicornis) is figured to have been introduced from the tropics of Asia or Africa. However, the ghost ant (Tapinoma melanocephalum) is so widespread throughout just about every corner of the globe that its place of origin cannot even be determined!
So, most, if not all of the ants that people encounter in the Marshalls are tramp species. Not all tramps are that destructive, however. Some, like the pharaoh ant (Monomorium pharaoris), the most common of all ants throughout the world, are basically domestic in nature. They not only bites people but also live where people live, often becoming bothersome household pests. "Kinal edrik" not only has the unpleasant habit of biting the people in whose homes it resides, but it also causes problems to open electrical circuits, causing various electrical appliances to stop working.
The bite of the larger, full-sized red "kinal" is extremely powerful. When a colony of these tramps bites and stings a person (this particular species does both), it is a painful experience that most victims will try to avoid ever happening again!
Yet painful as such attacks are, the damage that a few invasive ant species can cause to a native biota is much more serious.
Among the worst are the seemingly docile crazy and long-legged ants, which are bringing environmental disasters in their wake. In Ailinglaplap, one island that was formerly "mo" island (thus in a very natural state), began to be inhabited by people, but then was invaded by long-legged ants. The ants reportedly found the holes of the land crabs and coconut crabs to be convenient nesting places. Once established, these ant colonies proceeded to attack the crabs, blinding them and eventually destroying most of their abundant number from the entire island. This same species has caused similar problems on Christmas Island in the Indian Ocean. It is invading pristine - rainforests, killing the endemic land crabs. The ramifications appear to be endangering endemic species of lizards, seabirds and mammals.
Lots of horror stories are told from around the earth of the disasters caused by tramp invasive ants. On Hawaii, where there are no native ants, tramp species have been implicated in the extinction of many of that land's endemic spiders. In Tonga, the big-headed ant (Pheilole megacephala) has destroyed all native ants it has found in its expanding territory reportedly tearing them to pieces. The little fire ant (Wasmannia auropunctata), recently invaded the Solomon Islands, where it has blinded the local dog population, which then survive only a few years afterwards.
On other Pacific Islands, tramp ants have been known to come and go for no known reason. But they must still be taken seriously. On some islands, both fire ants and long-legged ants have killed hatchling turtles and young birds. Most reports deal with ground- nesting birds, but since many of the tramp ants are quite capable of climbing trees, there is no reason to feel that tree-dwelling birds, such as the endemic Micronesian pigeon (Ducula oceanica ratakensis), are immune from attack.
Invasives usually are said to be more likely to make headway into disturbed environments than untouched ones. But the long-legged ant on Christmas Island has been documented as destroying natural areas. Thus, what impact destructive such species could have on the essentially pristine bird and turtle havens of the northern atolls, and on some of the seemingly insignificant Marshalls' endemic species, such as the pseudoscorpions, is unknown.
Yet the sad fact is that such questions are often not addressed until after damage is already done. After all, ants are so small and easy to ignore - until it is too late! As entomologist James K. Wetterer, who specializes in tramp ants, has observed: "Humans tend to kill off the largest of native animals. The ccompanying ants help eradicate much of what remains."