Fire ants (Family Solenopsis) are troublesome ants in much of the United States. They have medically significant bites and stings and are a destructive invasive species. Recently, the discovery of Sicilian fire ants has the authorities of Italy worried.
According to the Guardian the ants so far appear to be confined to about 12 acres (5 hectares) around the city of Syracuse . According to the paper:
“The red fire ant, Solenopsis invicta, has a powerful sting, damages crops and can infest electrical equipment including cars and computers.
The ant, considered one of the most destructive invasive species, can rapidly form “super colonies” with multiple queens. The colonies prey on invertebrates, larger vertebrates and plants, destroying native plants and out-competing native ants, insects and herbivores for food.
The red fire ant is the fifth most costly invasive species in the world, spreading via human trade from its native South America into Mexico, the Caribbean, Australia and the US, where it causes an estimated damage of $6bn (£4.8bn) each year.
Researchers have identified 88 red fire ant nests across 5 hectares (12 acres) near the city of Syracuse, in Sicily, Italy. According to genetic analyses in a study published in Current Biology, the invasive colonies could have come from China or the US.” Links in original.
Researchers hope quick action can help control the ants and keep them from spreading to other nations.
In the United States fire ants have spread to many states and are beyond elimination. Texas has a significant problem with the ants, which infest 14 states from Florida to California. Puerto Rico is also infested.
Sicilian fire ants are potentially a serious problem for Europe. According to the United States Department of Agriculture (USDA) solenopsis ants do$6 billion in damage in the United States:
“Two species of Imported Fire Ants (IFA) were introduced into the United States from South America at the port of Mobile, Alabama. The black imported fire ant, Solenopsis richteri Forel, arrived around 1918 and the red imported fire ant, Solenopsis invicta Buren, in the late 1930’s. Both species probably came to the port in soil used as ballast in cargo ships. Today, IFA infest more than 367,000,000 acres in Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia and Puerto Rico. IFA have an impact on agriculture and natural resources by damaging crops, agricultural equipment, and impacting wildlife. As an urban pest, IFA are a nuisance pest and can cause allergic reactions including rare instances of anaphylactic shock in humans.”
The ants destroy crops, can ruin agricultural electrical equipment, and kill or outcompete native ants. They also attack native wildlife and native plants.
Fire ant densities in the United States are many times greater than in South America. That is believed to be because viruses and other diseases that kill the ants have not been imported with them. Their main enemy appears to be a fly that lays eggs on the heads of live fire ants. The hatchings then consume the ant. Spiders and other American predators will also eat the ants. So far no “Magic Bullet” has been found.
The USDA has begun a phorid fly breeding program to reduce the ant numbers but it is not expected to totally end the outbreak:
“In an effort to manage IFA within the generally infested areas of the U.S, APHIS, along with cooperators in Agricultural Research Service, universities, and states, implement an Imported Fire Ant Phorid Fly (Pseudacteon spp.) rearing and release program. The first 2 species of this biocontrol agent, P. tricuspis and P. curvatus, were released from 2002-2009 and have become established in more than 65% of the IFA quarantined area. In 2010-2014 there were multiple releases of two additional species, P. obtusus and P. cultellatus, both of which have become established in limited areas. Phorid flies will not be a stand-alone biological control agent for IFA but will be an important tool in IFA management programs.”