Solenopsis invicta:
(extracted from a report submitted to CGAPS (Coordinating Group
on Alien Pest Species) meeting on 22 March 2000 by Lloyd Loope)
The red imported fire ant (RIFA) is an extremely aggressive,
economically and environmentally destructive stinging ant that
has spread over much of the southern United States, despite federal
quarantine measures. It can invade a broad range of habitats,
with favorable habitat generally including areas where temperatures
are greater than 10°F and rainfall greater than 10"/yr.
The species is currently impossible to eradicate "once established".
This is due to the fact that the colonies grow fast, produce lots
of queens, produce queens during many months of the year, and
have queens that fly. Hence prevention and early detection (before
colonies begin to produce queens) is essential to preventing the
permanent establishment of this ant in Hawaii. If the species
becomes established in Hawaii, "controlling" ant numbers
for any length of time will be extremely difficult and costly
because 1.) current control methods have mixed results, and 2.)
queens can easily fly in from untreated areas and reinvade recently
treated areas. Hence, long term control of ant numbers requires
a monumental degree of cooperation and coordination among neighbors/adjacent
landowners, requiring everyone to treat their infested property
at the same time.
Impacts of this ant are primarily associated with its aggressive
stinging of humans and animals that disturb it. When a nest is
disturbed hundreds of workers will attack and relentlessly sting
the intruder. Stings are painful, and usually a victim will incur
multiple stings. Stings sometimes lead to secondary infection.
In addition to threatening human and animal safety, this ant also
damages electrical and farm equipment, and crops. In summary,
the RIFA inflicts serious health, economic, and environmental
impacts on communities it invades.
Solenopsis invicta would likely do very well in Hawaii. due
to the mild climate and prevalence of disturbed habitats (including
range and agriculture lands). If it were to become established
here. it would likely have serious negative effects in all sectors,
affecting public health. tourism, agriculture and livestock industries,
and natural ecosystems. With the recent establishment of this
ant in California, the chance of its being introduced to Hawaii
has increased, possibly, dramatically. Because of this, the ant
group has applied for $50.000 in funding from the EPA to develop
a prevention/quick response plan for this species. The money-will
be used to pay-the salary of an entomologist assistant to develop
the plan with input from the ant group. The in-kind match was
contributed by Bishop Museum, YES, MISC, and HDOA.
IMPACTS OF A RIFA INVASION
HUMAN HEALTH:
- Children and the elderly have the highest sting rate; people
that are less able to move (infants, elderly, infirm) and naive
individuals (tourists and people new to RIFA infested areas)
are most at risk of RIFA attacks.
- In RIFA infested areas, fire ant stings occur more frequently
than bee, wasp, hornet, or yellowjacket stings. Disturbing fire
ant mounds (nests) is almost unavoidable when walking in heavily
infested areas.
- In heavily infested areas fire ants sting more than 50% of
the human population each year.
- Approximately 1% of the population (or >10,000 Hawaii
residents) is hypersensitive to stings and could die if untreated.
- Fire ants are known to invade buildings including nursing
homes, schools, and other sites where people are at high risk
for stings.
- At least 80 deaths have occurred from fire ant stings incurred
outdoors; three deaths have been reported from indoor fire ant
attacks.
- In South Carolina 33,000 sting cases (5% of all cases) in
1998 required medical attention and an estimated 176 South Carolinians
were treated for RIFA induced anaphylaxis.
ECONOMIC
- Economic impacts of the RIFA are serious. RIFA's have caused
billions of dollars in damage and control costs since entering
the U.S.
- Texas: estimated annual economic loss due to fire ants is
$300 million
- Homeowners must control ant numbers on their property to
avoid ant attacks; ant treatments can be costly. What homeowners
spend each year on fire ant control:
Texas: up to $600/yr
Arkansas: $265/household a year
South Carolina: $30 or more/yr for most homeowners, totaling
$3-5million/yr
- Medical treatments of RIFA sting cases incur huge costs.
For example:
Texas: in five urban areas surveyed in 1998, costs totaled
$47.2 million.
South Carolina: costs totaled about $2.4 million in 1998
- Fire ants are attracted to and infest/damage electrical equipment.
Texas: infestation of electrical equipment (such as air
conditioners, airport runway lights. and traffic boxes) causes
an estimated $11.2 million in damages annually
- Fire ants result in reduced property values, structural damage,
and contaminated water systems. They can also discourage tourism
and recreational activities.
Texas: hunting, ranching, and recreational activities
have been greatly affected by the presence of fire ants, altering
behavior patterns and activities. In some areas, it is impossible
to sit in the grass or stand on a shoreline to fish without being
stung. This situation discourages tourism and poses liability
concerns to owners and managers of public areas. (Texas fire
ant management plan).
- Compliance with federal (USDA ) RIFA quarantine requires
treatment and certification of certain goods shipped outside
infested (quarantined) areas, at great cost to businesses affected.
For example:
S. Carolina nursury industry: certification plus broadcast
treatments can exceed $650/acre annually.
- In RIFA infested areas ants can prevent hand harvest of fruit
crops, where efficient, legal, controls are limited. Current
treatments may be applied only to borders and other non-crop,
areas of a field.
- Cattle producers suffer economic losses due to cattle injury
and death, hay production losses (from farm equipment damage
from mounds). ruined feed, ruined hay. electrical damage. shredder
damage (due to mounds), and pesticide costs. Losses are high,
for instance.
Texas.-the Texas cattle industry sees a $254.9 million
loss because of fire ants.
Texas: veterinarians reported 7,204 RIFA injury cases
annually. Most cases had multiple injuries. Veterinarians
reported 2.649 RIFA related animal deaths, with value of these
animals placed at nearly $3.5 million. Over half the deaths were
cattle.
Texas: over 80% of veterinarians cited fire ants as a
threat to livestock health and economic loss. Estimated economic
losses (for vet treatment and cattle lost) are estimated at
$2, 1 66,800.
S. Carolina: control in pastures, hay-fields. and recreational
turfgrass is at least $28/acre annually.
ANIMAL HEALTH (WILDLIFE/PETS)
- Texas: researchers report that nearly 70% of veterinarians
surveyed cited fire ants as a significant threat to animal health.
Small animals and pets accounted for over half of all veterinarian
reported RIFA inflicted injuries (not deaths).
- Most fire ant related animal deaths involve newborn or immobile
animals (including tied/penned pets).
- Pet injuries include:
mouth injuries due to infestation of pet bowls by ants
skin injuries to animals penned, caged, tied and unable
to escape
- Wildlife is seriously affected by fire ant infestations.
RIFA have opportunistic feeding habits and actively prey
on invertebrates, vertebrates, and plants. In general, as
the RIFA invades an area, the diversity and abundance of native
arthropods and vertebrates plummets.
Animals susceptible to predatory attack by foraging RIFA
include anything that is immobile and unable to escape, including
the eggs and young of most vertebrates.
Ingestion of RIFA negatively impacts insectivorous species.
RIFA have been implicated in numerous fish kills throughout
the southeast.
Wildlife reported in the scientific literature to be killed
by RIFA include: invertebrates, birds, lizards, turtles,
small mammals, and the young of large mammals (fawns).
Species known to be negatively impacted by RIFA include:
colonial waterbirds (egrets, herons, spoonbills. cormorants,
and gulls), wood ducks. endangered least terns, cliff swallows,
crested caracara, bobwhite quail, loggerhead sea turtle,
endangered green sea turtle, yellow fin shiners, white tailed
deer, several species of small mammals, several species of
invertebrates.
USDA entomologists work with many environmental and conservation
groups in the southern U. S. to keep fire ants from harming
endangered species, such as Stock Island tree snails, gopher
tortoises, Florida grasshopper sparrows, saltmarsh rabbits,
and sea turtles.
Waterbird colonies experience up to 100% hatchling mortality
in RIFA infested sites. compared to sites where RIFA are controlled.
Lower invertebrate diversity.
ENVIRONMENT/QUALITY OF LIFE
- Pesticide contamination -overuse and misuse of fire ant mound
treatments are blamed for contamination of surface runoff water
in Texas and California.
- Restricted outdoor use.
In campsites in infested areas of public parks. it is
often difficult to put up or take down a tent without being
stung by fire ants.
The fear of being stung influences people's choice of
recreation/outdoor activities. In some infested areas, playgrounds,
parks and picnic areas lie abandoned-unused because of the
presence of fire ants.
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