1. ANTS
(Order: Hymenoptera; Family: Formicidae)
[Illustration: Fire Ant Mound]
[Illustration: Harvester Ant Mound]
Identification. Like other Hymenoptera, females of dangerous ant species
have a stinger at the posterior tip of the abdomen. Their constricted
“waist” between the thorax and posterior abdomen and their elbowed
antennae distinguish them from similar insects. The dangerous United
States species belong to genera _Solenopsis_ (fire ants) or
_Pogonomyrmex_ (harvester ants). The easiest way to distinguish these
ants is by their mounds. Fire ants build elevated earthen mounds 8-90 cm
(3-36 in) high, leaving the surrounding vegetation relatively
undisturbed. In contrast, harvester ant mounds are usually flat or
slightly elevated and are surrounded by a defoliated area 0.6-3 m (2-10
ft) or more in diameter. Also, harvester ants are 2 to 3 times larger
than fire ants.
Distribution. The Florida harvester ant, _P. badius_, distributed
throughout the Southeastern States, is the only harvester ant known to
occur east of the Mississippi River. West of the Mississippi, the red
harvester ant (_P. barbatus_), the California harvester ant (_P.
californicus_), and the western harvester ant (_P. occidentalis_) are
found in different individualized distribution areas. The two most
important fire ant species were introduced into the United States from
South America. The red imported fire ant (_S. invicta_) was introduced
about 1940 and is well established in the Southeastern States.
Currently, this ant infests Alabama, Arkansas, Florida, Georgia,
Louisiana, Mississippi, North and South Carolina, and Texas. The black
imported fire ant (_S. richteri_) was introduced about 1918; its
distribution is limited to an area in northeastern Mississippi and
northwestern Alabama. Two less important native species, _S. geminata_
(tropical or native fire ant) and _S. xyloni_ (southern fire ant), occur
in localized areas of a few southern states.
Biology/Behavior. Ants of the _Solenopsis_ and _Pogonomyrmex_ genera are
diurnal soil-inhabiting insects that prefer to nest in open areas. These
ants are social insects; their colonies consist of at least one
reproductive queen, several males, and many nonreproductive female
workers. Fire and harvester ants are particularly dangerous because
workers defending their nest can inflict repeated stings, and multiple
human envenomizations may occur when a victim comes in contact with a
mound.
Avoidance/Control. Familiarization with the appearance of the ant mounds
is necessary in order to avoid them and prevent accidental
envenomizations. Since small children are often the victims of multiple
stings, parents should insure that the mounds of dangerous ant species
are not present in play areas. This is particularly important where the
red imported fire ant occurs. Mound treatments with mirex have been
effective in controlling _Solenopsis_ and _Pogonomyrmex_ ants. The
Environmental Protection Agency limits the use of this insecticide, and
it must be applied in strict accordance with EPA and product label
instructions.