- Two
nodes
- Worker
size: 1/8 to 1/4 inch (3 to 7 mm)
- Uneven
thorax o 12 antennal segments, 3-segmented club
- One
pair of spines on thorax
- Color
varies from brown to black to reddish

ID Tip. The
pedicel (nodes) attaches to the top of the gaster instead of the
middle. The abdomen, when viewed from above, is shaped like a
heart. Acrobat ants get their name from the habit of holding
their abdomens above their thorax - like acrobats - when the
workers or colony are disturbed.
Feeding Habits. Acrobat ants
feed on a wide variety of foods including both sweets and
proteins. Inside structures, acrobat ants will feed on household
foods and show a preference for sweets.
Key Inspection Tips.
Inspecting for colonies of acrobat ants is similar to an
inspection for carpenter ants. When workers are found foraging
indoors, the first place to inspect is the exterior of the
structure.
Outside: Inspect the building's foundation for trails
of workers. Workers may also be observed trailing on tree and
shrub branches that brush against the structure. Wires and
cables are another avenue for worker ants trailing onto the
structure. The eaves of structures should be inspected for ant
trails or workers entering cracks in the soffits. Signs of
excess moisture should be noted along the fascia boards and
under soffits. Such signs include warped boards, peeling paint
and fungi on the surface of wood. Suspect areas in the soffits
will need to be inspected more closely using a ladder.
Inside:
Acrobat ant colonies are most often found in areas where water
leaks have occurred. It is important to ask the customer if they
are aware of any water leaks in the building within the past
several years. These areas should be inspected first. A moisture
meter is helpful in locating areas of high moisture. Firewood
stored inside should also be checked for ant colonies.
Termite-damaged wood should be probed for the presence of
colonies, particularly in basements and crawlspaces.
When
acrobat ants infest wood damaged by other insects, they often
clear out bits of dirt and dead insects. This debris is often
deposited in piles in visible areas and indicates the presence
of an ant colony. Bits of foam in window sills or on door
thresholds may indicate ants infesting foam insulation.
Professionals may occasionally mistake these bits as evidence of
powderpost beetles. Care should be taken to confirm the actual
type of insect present.
Contributing Conditions. Dead wood and
wood debris, as well as areas - both indoors and outdoors - that
contain a high level of moisture content should be checked for
ant activity. Any water leaks that are present must be
corrected. Clogged gutters must be cleared. Tree and shrub
branches which brush against the structure should be cut back.
As many cracks and holes as possible in the building's exterior
should be sealed.
Control
Solution
- One node
- Worker size: 1/8 to 1/4 inch (3.5 to 7 mm)
- Uneven thorax
- 12 antennal segments, no club
- Head and thorax
are reddish
- Abdomen and legs are dark
- Circle of hairs
present at tip of abdomen

I.D. Tip: This ant builds large nests that are usually easy
to spot. Upon a quick glance, this ant resembles red and black
species of carpenter ants, but the Allegheny mound ant is easily
distinguished by its uneven thorax.
Feeding Habits. This ant is
omnivorous and feeds on a wide variety of foods, including both
dead and live insects. It will tend homopterous insects (aphids,
mealybugs and scales) that live in trees and shrubs for the
"honeydew" they produce. They protect these insects
from predators.
Key Inspection Tips. The Allegheny mound ant is
found throughout the upper Midwest to the New England states and
south to Georgia. These ants build large mounds, sometimes
mistaken to be those of fire ants, which has led to "fire
ant scares" in some northern states.
This ant does not
enter structures, but can be found living in lawns of houses and
commercial structures that are adjacent to fields or wooded
areas. The Allegheny mound ant causes no real harm, but it will
bite if the mound is disturbed. For this reason, many homeowners
may wish to have the mounds on their property treated. Finding
the mounds built by Allegheny mound ants is usually quite easy.
Customers most often will already have identified where the
mounds are located. An inspection of the property should be
completed to determine if any newly formed mounds are present
that may not be readily visible. Other than lawns, mounds may
also be located in hidden areas under shrubs or ground-covering
ivy in landscape beds.
Single colonies may consist of several
closely-situated mounds tied together into a larger, supercolony.
The workers excavate tremendous amounts of soil in digging their
underground galleries. This excavated soil forms the mounds
characteristic of this ant. It is not uncommon to find mounds up
to 3 feet in diameter in undisturbed areas, such as fields or
wooded areas. Homeowners, however, will rarely allow mounds on
their property to grow larger than 1 foot in diameter before
seeking to control them.
Contributing Conditions. The condition
which contributes most to the presence of the Allegheny mound
ant is lawns and landscaping around homes and other structures
that are located next to fields or wooded areas.
Often, little
can be done to change this factor. A field of weeds can be mowed
regularly which may keep the numbers of colonies down; however,
this may not be possible if the adjacent field is not owned by
you.
Control
Solution
| COMMON
NAME: |
Argentine
ant |
| SCIENTIFIC
NAME: |
Iridomyrmex
humilis (Mayr) |
| CLASS/ORDER/FAMILY: |
Insecta/Hymenoptera/Formicidae |
| METAMORPHOSIS: |
Complete |
|
INTRODUCTION.
This species, which is native to Argentina and Brazil, was
probably introduced at New Orleans via coffee ships from Brazil
before 1891. Argentine ants are found in the southern states and
in California, with isolated infestations in Illinois, Maryland,
Missouri, Oregon, and Washington.
RECOGNITION.
Workers monomorphic, about 1/16" (2.2-2.6 mm) long; queens
about 1/8-1/4" (4-6 mm) in length. Body varies from light
to dark brown. Antenna 12-segmented, without a club. Thorax
lacks spines, profile unevenly rounded. Pedicel 1-segmented.
Gaster with anal opening slitlike, lacking circlet of hairs.
Stinger absent but can bite on provocation. Workers emit a stale
greasy or musty odor when crushed.
SIMILAR GROUPS.
(1) Odorous house ant (Tapinoma sessile) has pedicel/node nearly
hidden by front edge of abdomen/gaster, emit a sweetish rotten
coconut odor when crushed. (2) Crazy ant (Paratrechina
longicornis) with legs very long in relation to body size,
antenna! scape (1st segment) at least 2 times head length, anal
opening circular, surrounded by circlet of hairs. (3) Other
small dark ants with 2 nodes/segments in pedicel and/or thorax
with 1 or more spines/teeth on upper surface.
BIOLOGY.
Colonies are located in moist situations near a food source.
They include a few hundred to several thousand workers and many
queens; numbers fluctuate seasonally. In the autumn, outside
colonies join together to form huge overwintering nests.
Development time (egg to adult) is 33-141 days, averaging 74
days. Winged female reproductives are rarely seen because mating
takes place inside the nest. The workers are very aggressive and
usually eliminate other ant species and some other insects from
the area. However, ants from different Argentine ant colonies
are friendly and do not fight.
HABITS.
Inside, these ants usually nest near a moisture source such as
water pipes, sinks, potted plants, etc. The workers follow
regular trails when foraging, and winged queens can sometimes be
found among trailing workers. Workers commonly tend
honeydew-producing insects. The preferred foods are sweets such
as sugars and syrup but they will feed on almost every kind of
food including meats, eggs, oil, fats, etc.
Outside,
Argentine ants typically live in shallow nests located in moist
situations such as under boards and stones, beneath plants,
along sidewalks, etc. This ant prefers sweets such as honeydew'
fruit juices, and plant secretions, but also steals seeds,
attacks poultry chicks, disrupts bee hives, etc. Their habit of
crawling over everything including refuse, sewage, sputum,
carrion, etc. affords them the opportunity to transport the
causative disease organisms for dysentery, etc.
Argentine ants
invade buildings in large numbers when conditions outside are
either too wet or too dry for them to live. Also, a decrease in
their honeydew supply sends them indoors seeking sweets. They
will readily trail along tree and shrub branches, as well as
utility lines/wires to gain entrance.
CONTROL.
Location of the nest(s) and its treatment with a residual
insecticide is ideal; try following ants back from the food
source. Be sure to pull back the grass from around foundation
walls and the edges of concrete sidewalks and driveways because
these ants will trail below the grassline where they are not
visible. Baiting and use of insecticide dust in the voids of the
outside ground-floor walls is the preferred treatment. Outside
perimeter barrier treatments are essential and must be well
maintained.
Control
Solution
- Two nodes
- Worker size: 1/6 to 1/8 inch (1.5 to 3.5 mm)
- Uneven shape of thorax
- 12 antennal segments, 3-segmented club
- One pair of spines on thorax
- Light brown to dark reddish
brown

ID Tip. Big-headed ants have
two distinct sizes of workers - major workers and minor workers.
Major workers are easily recognized by having very large heads
in proportion to their bodies.
Feeding Habits. Big-headed ants
feed on live and dead insects, seeds and the honeydew produced
by homopterous insects (e.g., aphids, mealybugs and scale
insects). In houses, they seem to prefer protein foods, such as
meats and peanut butter, but will also feed on greases and
sweets, such as fruit juices.
Key Inspection Tips. Big-headed
ants forage in trails of a few up to hundreds of workers. These
trails can usually be located without too much difficulty along
sidewalks and foundations and up the extension sides of
buildings.
Inside: Big-headed ants trail along baseboards and
are commonly found foraging under the edges of carpets. When
these ants are found indoors, an attempt should be made to
follow the foraging workers back to the site where the colony is
located. If the ants are entering and exiting from under the
wall, an inspection outside along the foundation is necessary to
see if the ants inside are coming from a colony located
outdoors.
Outside: Grass or other vegetation should be pulled or
raked away from the foundation of the building and along
driveways and sidewalks. Colonies are often found in the soil
beneath the grass next to the building's foundation, and this is
one of the first areas that should be checked. Big-headed ants
also will nest and forage under the grass line along sidewalks
and patios where they cannot be seen. Mulch should be raked back
from the bases of trees and shrubs to check for ant colonies.
Items in contact with the soil, such as logs, stones, firewood
and other debris, should be lifted to check for colonies.
Contributing Conditions. As with most ants, moisture is a
limiting factor in the survival of bigheaded ants. If conditions
exist which result in excess moisture (e.g., poor foundation
drainage or water leaks), they should be corrected. As many
cracks in the exterior walls as possible need to be sealed.
If
possible, a vegetation-free border should be installed around
the base of the foundation to make the area less attractive to
ants and to make inspections of the foundation easier. This
vegetation-free border should contain gravel or small stones
over plastic sheeting and not bark chips or mulch. Items under
which big-headed ants could nest should be removed. These items
include boards, bricks, stones and logs. Firewood should be
stored off the ground and as far from the structure as possible.
Control
Solution
- One
node
- Workers
size: 1/5 to 1/2 inch (9 to 13 mm)
- Evenly
rounded thorax
- 12
Antennal segments
- The
head, thorax and petiole is yellowish-red to red, abdomen is
black
- Body
covered with long, yellowish hairs

I.D. Tip.
This species of carpenter ant, in the subgenus Myrmothrix, can
be a serious structural pest in Florida and other parts of the
extreme southeast U.S.
Feeding Habits. Carpenter ants feed on a wide variety of
foods. A favored food is the sweet honeydew produced by aphids,
mealybugs and scales. Carpenter ant food preferences can also
change over the course of the seasons.
During the spring when the larvae are growing, most of the
foraging targets protein foods. A switch is made to
carbohydrates (e.g., honeydew) during the summer when adult
workers are at their most numerous.
Key Inspection Tips. This ant is very opportunistic in
selecting its nesting sites. One of the more common nesting
sites is under rocks, logs, landscape timbers and debris lying
on the ground. Dead tree branches, rotting stumps and moist
timbers in buildings are other nesting sites. Piles of trash or
other debris seem to be highly preferred for nesting,
particularly in developed areas where trees are less
available.
Inside homes, nests may be discovered most often in wall voids,
behind dishwashers and under insulation in attics. Florida
carpenter ant satellite colonies were also found in the
following unusual sites: air conditioning units, switch outlet
boxes in the wall, a ceiling light fixture, a water cooler, book
shelves, electronic games, wall clocks, potted plants, debris in
rain gutters, water beds, spa filters, a steam iron, a VCR,
clothes pins stored in a milk jug and the rubber seal of a
refrigerator.
When dealing with infestations of Florida carpenter ants, any
item lying in contact with the ground could harbor a colony.
This is particularly true of piles of items, such as lumber,
bricks, firewood, or trash. Items lying on top of mulch in
landscape beds provides good nesting sites for colonies of this
species.
Contributing Conditions. Moisture and dead wood are the
two primary conditions present in and around structures that
contribute to carpenter ant infestations. Structures which are
located in wooded areas or on wooded lots have plenty of both
and, therefore, have more potential for problems.
Structures without many trees on the property, however, can also
experience infestations. This is particularly true if the
structure contains sites with excessive moisture, thus creating
an ideal area for carpenter ants.
If conditions which are contributing to the carpenter ant
infestation are not corrected, the carpenter ant problem may not
be eliminated.
Control
Solution
| HERCULEANUS
CARPENTER ANT |
- One
node
- Worker
size: 1/8 to 1/3 inch (3.5 to 9 mm)
- Evenly
rounded thorax
- 12
antennal segments
- The
body of this species is mostly black with the rear portion
of the thorax, the petiole and the legs dark red.
I.D. Tip.
This species of carpenter ant occurs in the northern United
States from the East Coast to the West Coast. The ant is
reportedly the second most common structure-infesting species in
Minnesota.
Feeding Habits. Carpenter ants feed on a wide variety of
foods, including dead insects. A favored food is the sweet
honeydew produced by aphids, mealybugs and scales. Carpenter ant
food preferences can also change over the course of the seasons.
During the spring when the larvae are growing, most of the
foraging targets protein foods. A switch is made to
carbohydrates (e.g., honeydew) during the summer when adult
workers are at their most numerous.
Key Inspection Tips. This ant nests primarily in wood and
can be found in the same wooded areas as the black carpenter
ant, C. pennsylvanicus, and the western carpenter ant, C. modoc.
It is rarely seen in deforested areas, such as much of North
Dakota. Its colonies are mediumsized, numbering from several
thousand to as much as 12,000.
Carpenter ants get their name from their habit of hollowing out
wood to build a nest. They require a moist or humid environment
in which to establish a colony. They usually prefer to nest in
moist or damaged wood, but they will nest in dry, sound wood. In
structures, they are commonly found where water has leaked and
soaked the surrounding wood. Leaks often occur around plumbing
in kitchens and bathrooms, in roofs, and the soffits where
gutters are absent or are poorly installed. Poorly ventilated
attics and crawlspaces create an ideal, humid environment that
is attractive to carpenter ants.
Inside buildings, carpenter ants readily nest in any moist or
humid, hollow void. In fact, a great many of the colonies found
inside buildings will be satellite colonies and these will
usually be associated with voids rather than be inside wood.
Colonies can be found living in voids which are seemingly dry
and satellite colonies are frequently discovered under and
behind insulation in attics, basements and crawlspaces.
Contributing Conditions. Moisture and dead wood are the
two primary conditions present in and around structures that
contribute to carpenter ant infestations. Structures which are
located in wooded areas or on wooded lots have plenty of both
and, therefore, have more potential for problems.
Structures without many trees on the property, however, can also
experience infestations. This is particularly true if the
structure contains sites with excessive moisture. If conditions
which are contributing to the carpenter ant infestation are not
corrected, the carpenter ant problem may not be eliminated or
will return soon.
Control
Solution
- One
node
- Evenly
rounded thorax
- 12
antennal segments
- Worker
size: 1/5 to 1/2 inch (9 to 13 mm)
- Abdomen
has long yellow hairs, and circle of hairs at tip

I.D. Tip:
This ant is recognized by its black body and dark red
legs.
Feeding Habits. Carpenter ants feed on a wide variety of
foods, including dead insects. A favored food is the sweet
honeydew produced by aphids, mealybugs and scales. Carpenter ant
food preferences can also change over the course of the seasons.
During the spring when the larvae are growing, most of the
foraging targets protein foods. A switch is made to
carbohydrates (e.g., honeydew) during the summer when adult
workers are at their most numerous.
Key Inspection Tips. Camponotus modoc is the most common
structure-infesting ant along the west coast, especially the
Pacific Northwest. Colonies may be quite large with up to 50,000
workers. A mature colony of C. modoc along the Pacific Coast may
have up to 20 or more satellite colonies which is a major factor
that makes this species difficult to control. Foraging activity
for C. modoc in the Northwest occurs between April and October
with May to September serving as the peak foraging period.
C. modoc has been shown to make distinct, visible trails in
lawns and landscaping areas from the main colony to satellite
colonies. These trails are often well worn and up to two inches
wide. Trails are also not necessarily above the ground as
subterranean trails have been discovered by gardeners and
termite control professionals when they dig in the soil.
Typically, these subterranean trails follow tree roots several
inches below the soil surface, but trails have been discovered
as deep as 4 feet along tree roots.
Main colonies usually occur outdoors in stumps, living trees,
landscape timbers, etc. with up to 20 or more satellite colonies
located in other trees, landscape timbers and voids and wood
timbers in buildings. This species infests more structures than
any other Camponotus species in the Pacific Northwest.
Contributing Conditions. Moisture and dead wood are the
two primary conditions present in and around structures which
contribute to carpenter ant infestations. Structures which are
located in wooded areas or on wooded lots have plenty of both
and, therefore, have more potential for problems with carpenter
ants.
Structures without many trees on the property, however, can also
experience carpenter ant infestations. This is particularly true
if the structure contains numerous sites with excessive
moisture. If conditions which are contributing to the carpenter
ant infestation are not corrected, the carpenter ant problem may
not be eliminated or will return soon. Correcting these
conditions is the most important step in the long-term
management of carpenter ant infestations.
Control
Solution
| COMMON
NAME: |
Carpenter
ant |
| SCIENTIFIC
NAME: |
Camponotus
spp. |
| CLASS/ORDER/FAMILY: |
Insecta/Hymenoptera/Formicidae |
| METAMORPHOSIS: |
Complete |
INTRODUCTION.
The black carpenter ant, Camponotus pennsylvanicus (DeGreer),
is a native species and the common species in the east. Camponotus
modoc Wheeler is the common western species. These ants get
their common name from their habit of hollowing out galleries in
pieces of wood for nesting purposes. This nesting habit can
result in structural damage. Carpenter ants are found throughout
the United States.
RECOGNITION.
Workers polymorphic, large (1/8-1/2" or 3.5-13 mm) but vary
greatly in size; queens about 112-518" (13-17 mm) long.
Color black, combinations of red and black, or completely red or
brown. Antenna 12-segmented, without a club. Thorax
lacks spines, profile evenly rounded
on upper side. Peel 1-segmented. Gassier with anal
opening round, surrounded by circlet of hairs.
Stinger absent. Workers capable of emitting a strong formic acid
odor.
Camponotus
pennsylvanicus with workers about 1/4-1/2" (6-13
mm) long and completely black except top of gaster with long,
pale yellowish hairs pressed against its surface. Camponotus
modoc with workers about 1/4-1/2" (5-11 mm) long,
dull black with reddish legs and with golden hairs covering
abdomen. Queens up to 5/8+" (17+ mm) long. Other species
black, various combinations of red and black, or completely red
or brown. Although carpenter ants do not sting, their bites can
be quite painful, especially when they inject formic acid into
the wound.
SIMILAR GROUPS.
(1) Dark field (Formica spp.), larger yellow (Acanthomyops
interjectus), and Allegheny mound (F. exsectoides) ants have
profile of thorax not evenly rounded, with distinct impression(s);
in addition dark field ants with front and hind margins of node
steeply or equally sloped. (2) Velvety tree ants (Liometopum spp.)
lack circular anal opening surrounded by circlet of hairs. (3)
Other medium to large dark ants with 2-segmented pedicel.
DAMAGE.
The only external indication of infestation other than the
presence of workers and/or swarmers is the appearance of small
openings or windows on the surface of the wood. Through these,
the workers expel debris which consists of sawdust-like shavings
and/or fragments of insulation and insect body parts. The
accumulation of such debris below such holes is a good
indication of an infestation.
Inside, the
galleries follow the softer spring wood with numerous
connections through the harder/dark summer wood. The gallery
walls are smooth, with a sand-papered appearance. The active
galleries are kept clean of debris.
They prefer to
attack wood softened by fungus and are often associated with
moisture problems.
BIOLOGY.
Black carpenter ant colonies are of moderate size, usually
containing over 3,000 workers (up to 10-15,000 including
satellite nests) when maturity is reached in about 3 to 6 years.
The typical western carpenter ant (C. modoc) mature
colony contains about 10-20,000 workers, with large colonies
having up to 100,000 workers. Developmental time (egg to adult)
for workers takes at least 60 days. Workers are polymorphic,
with majors, minors and intermediates present. There is usually
only one functional, wingless queen per colony. Swarmers are not
produced until the colony is more than 2 years old, usually
3.5-4 years old for C. pennsylvanicus and often 6-10
years old for C. modoc. Swarmers appear from May until
August in the east and from February through June in the west.
HABITS.
Most carpenter ant species establish their first nest in decayed
wood and later expand or enlarge this into sound wood. Inside,
nests are located in wood (preferably softened by fungus rot),
in insulation, and/or in wall voids. Workers are a nuisance when
out searching for food but are destructive to timbers utilized
for nesting activities. Outside, nests are typically located in
rotting fence posts, stumps, old firewood, dead portions of
standing trees, and under stones or fallen logs.
The presence of a
carpenter ant nest is sometimes indicated by a rustling sound
coming from wall voids or from wood where the colony is located.
Otherwise, the emergence of swarmers indoors may be the first
indication of an indoor colony.
Carpenter ants
feed primarily on insect honeydew, plant and fruit juices,
insects, and other arthropods. Inside, they will also feed on
sweets, eggs, meats, cakes, and grease.
The workers
forage for distances of up to 300 feet (91.4m) from the nest.
They typically enter buildings around door and window frames,
eaves, plumbing and utility lines, and shrub and tree branches
in contact with the building. Although some workers are active
during the day, most activity is from dusk till dawn, with peak
activity between 10 pm and 2 am. The trail between the parent
and satellite nest is usually about 1/4-13/16" (6-20 mm)
wide and is kept clear of vegetation and debris. It usually
follows contours but typically will cut across lawns.
CONTROL.
The first step is to determine if the ants present are merely
foraging inside or if there is a nest inside. The best
indication of a nest is the presence of sawdust piles containing
insect body parts. Another indication is the sound produced as
the workers remove wood to expand the nest. Outside, check
around the building's perimeter for foraging trails, especially
in the direction of trees and shrubs; easiest to locate between
sunset and sunrise when the ants are most active.
The second step
is to locate any inside nests. Look for sawdust piles with
insect body parts. Listen for ant sounds mentioned above;
listening devices are helpful. Gently tap with a screwdriver,
etc. all exposed wood such as floor joists, sill plates, roof
rafters, etc. and listen for sound changes; nest cavities give a
hollow or dull ring. Check suspicious areas with a knife blade
which will readily penetrate infested wood. Be sure to check
crawl spaces, basements, and attics. Carpenter ants have a
network of trails they follow throughout a structure and often
use the tops of electrical Wires and water pipes, so be sure to
check where these are. A moisture meter can be helpful in
locating areas of higher moisture in which the ants prefer to
locate their initial nests.
The third step is
to determine if the inside colony is a parent or satellite
colony. Inspect and search. Detection of a trail directs one to
the parent colony. For effective control, it is imperative to
locate and eliminate the parent colony.
Once the colony
or colonies are located, they should be treated directly with an
appropriately labeled pesticide. Inside, this may involve
drilling wall voids and applying dust and/or drilling wood
members and pressure injection. Barrier treatment is effective
in preventing entry, with wettable powder and microencapsulated
formulations working best. All branches of trees and shrubs in
contact with the building must be trimmed back. Be sure to check
where electrical and water lines enter the building and caulk
any gaps. Sometimes treating the bottom 3-6 feet (1-2 m) of tree
trunks and/or utility poles is helpful.
Control
Solution
- One
node
- Evenly
rounded thorax
- 12
antennal segments
- Thorax
is red, while rest of this ant's body is black
- Worker
size: 1/4 to 1/2 inch (7 to 13 mm)
I.D. Tip. The
thorax of this ant is red with the rest of the body and legs
black.
Feeding Habits. Carpenter ants feed on a wide variety of
foods, including dead insects. A favored food is the sweet
honeydew produced by aphids, mealybugs and scales. Carpenter and
food preferences can also change over the course of the seasons.
During the spring when the larvae are growing, most of the
foraging targets protein foods. A switch is made to
carbohydrates (e.g., honeydew) during the summer when adult
workers are at their most numerous.
Key Inspection Tips. This species occurs from the West
Coast east to the Dakotas and Alberta, Canada and south to
Mexico. This species is a serious structural pest, second only
to C. modoc in Washington state. Colonies can be very large, up
to 100,000 workers, and will have multiple queens. It will nest
in sound wood but prefers fungus- or moisturedamaged wood. Its
nesting habits outdoors are varied, ranging from dead trees and
rotting stumps to beneath rocks and logs on the forest floor. It
has also been observed to nest in the heartwood of living
trees.
When looking for carpenter ants, structural guidelines should
remain a focus of the inspection. Edges of sidewalks, fences,
decks and fascia boards will often have ants trailing along
them. By following the structural guidelines as they connect
with one another, the trail may be more easily followed.
Signs of high moisture content in structural wood - water
stains, peeling paint, fungi, etc. - can be an indicator of
areas where carpenter ants are present. A moisture meter is
handy in determining where leaks may be present or have occurred
in the past. Hollow porch columns are common sites for carpenter
ant activity. Foraging workers on tree trunks may indicate a
colony located somewhere up in the tree. Tree limbs which brush
against the walls or the roof of the structure should be
inspected for workers trailing onto the structure.
Contributing Conditions. Moisture and dead wood are the
two primary conditions present in and around structures which
contribute to carpenter ant infestations. Structures which are
located in wooded areas or on wooded lots have plenty of both
and, therefore, have more potential for problems with carpenter
ants. Structures without many trees on the property, however,
can also experience carpenter ant infestations. This is
particularly true if the structure contains numerous sites with
excessive moisture. If conditions which are contributing to the
carpenter ant infestation are not corrected, the carpenter ant
problem may not be eliminated or will return soon. Correcting
these conditions is the most important step in the long-term
management of carpenter ant infestations.
Control
Solution
- One node
- One size of
worker, 1/10 inch (2 to 2.5 mm)
- Uneven thorax
o Scape (first segment of antenna) is shorter than the
head
- Brown to very
dark brown in coloration

ID Tips.
Eyes are relatively large in comparison to the size of the
head.
Feeding Habits. The cornfield ant is particularly fond of
sweets, but it will readily feed on both live and dead insects.
Indoors, this ant will be attracted to sweet foods, but may feed
on literally any crumbs that fall to the floor.
Key Inspection Tips. Numerous mounds in lawns are a
common sight in those areas where cornfield ants are abundant.
The nests are very common in fields and in and around homes,
where they may be found between bricks in the walk, beneath
rocks, in cracks in the pavement, in the lawn, etc. Extended
colonies may occur where a group of mounds are interconnected by
foraging trails. Nests may also be formed in landscape mulch or
in the soil beneath objects lying on the ground.
This ant will nest in walls and floors in association with water
leaks and poor drainage and ventilation, hence its nickname of
"moisture ant." It is particularly prevalent around
bathtubs and showers where leaks are present or have occurred.
Most often, such colonies are associated with fungus damage and
decay; therefore, the moisture condition has likely been present
for many months. Moisture-damaged wood is often hollow, creating
galleries similar to those of carpenter ants. Old termite and
carpenter ant galleries may occasionally be occupied by this
species. The cornfield ant will construct tubes or nests of soil
inside walls. In a few cases, colonies will locate in the soil
beneath slabs and enter through expansion joints and other
cracks in the slab. Such subslab nests occur more frequently in
commercial buildings. Small piles of soil displaced from beneath
the slam may be seen on top of slabs under which colonies are
located. Nests under slabs outside, such as sidewalks and
patios, may also be determined by piles of displaced soil.
Outside: The cornfield ant readily establishes strong trails
that are easy to find. The trails will typically follow
structural guidelines, such as the edges of sidewalks. Colonies
should be easy to locate by the piles of displaced soil
associated with soil nests. Any item in contact with the ground
should be inspected underneath for colonies.
Contributing Conditions. Outdoors, contributing
conditions are negligible with this ant. Exterior cracks should
be sealed to help prevent foragers from entering. Inside, water
leaks must be repaired and the surrounding void and wet wood
thoroughly dried. In many cases, correcting the moisture
conditions results in the ants vacating the structure. Severely
damaged wood should be replaced. Steps should be taken to
improve the ventilation in poorly ventilated crawlspaces to make
these areas less attractive to ants.
Control
Solution
- One
node
- One
size worker: 1/8 inch (3 to 3.5 mm)
- Uneven
thorax o 12 antennal segments, no antennal club
- Circle
of hairs on tip of abdomen
- Dark
brown to black coloration

ID Tip.
Extremely long legs and antennae. The first segment of antennae
is more than twice as long as the head. Crazy ants get their
name from their habit of running about very erratically with no
apparent sense of direction.
Feeding Habits. Crazy ants feed on a variety of foods,
other insects, grease and sweets.
Key Inspection Tips. Trails of crazy ants will usually be
quite visible on walkways, foundations, and the sides of
buildings. Once a trail of ants is found, workers carrying bits
of food or whose abdomens appear swollen with food or water will
usually be returning to the colony. The trail should be followed
in the direction in which these workers are heading.
Outside: Any object lying on the ground, such as lumber, stones,
or trash, is a potential nesting site. Piles of any item are
especially coveted by this ant (and other ants), particularly
items in shaded, damp areas. Landscape mulch should be moved
away from the building foundation and the base of trees and
shrubs to check for ant colonies. Crazy ants forage long
distances from the colony so a thorough inspection of the entire
property is necessary. Branches of trees and shrubs brushing
against the building should be checked for trails of foraging
ants. The sides and edges of soffits on homes are often a site
for foraging crazy ants. Nests in soffits and attics are not out
of the question, especially if the attic is poorly ventilated
and humid or excess moisture is evident in the soffits. Crazy
ants have also been observed to live in gravel and underneath
wood on the flat roofs of commercial buildings. When
infestations occur on the upper floors of tall buildings, the
roof should be inspected.
Inside: Crazy ants will nest in wall voids and in the soil of
potted plants and atriums. The workers will forage along
baseboards both above and below the edge of carpets. When crazy
ants are observed foraging indoors, an attempt should be made to
follow the trail to the point where the ants enter under a wall
or through a crack (e.g., under a doorway). If ants are observed
entering under a wall, the foundation and wall outside that area
may reveal ants entering from a colony located outdoors.
Contributing Conditions. If conditions exist which result
in excess moisture they should be corrected. Branches of trees
and shrubs need to be pruned away from the structure's roof and
walls. As many cracks in the exterior walls as possible need to
be sealed. Items under which crazy ants could nest should be
removed.
If possible, a vegetation-free border should be installed around
the base of the foundation to make the area less attractive to
ants and to make inspection easier. This vegetation-free border
should contain gravel or small stones and not bark chips or
mulch. Mulch and bark chips hold moisture, creating an ideal
nesting site for ants.
Control
Solution
- One node
- One size
worker, typically 3/8 inch (10 mm)
- Uneven
thorax
- Color varies
from black, brown, tan, reddish, or red and black
- Circle of
hairs on tip of abdomen

ID Tip.
Closely resemble carpenter ant in appearance, however, field
ants have an uneven thorax.
Feeding Habits. The ants feed on a wide variety of
materials, such as live and dead insects and the honeydew
produced by aphids, mealybugs and scales.
Key Inspection Tips. Various species of Formica
"field ants" are found throughout much of the United
States. These ants are a particular problem in midwestern and
northern states. Field ants are common around structures, but
will only occasionally be seen indoors.
Foraging workers are quite common, however, on patios,
sidewalks, decks and the foundations of buildings where they can
be mistaken for carpenter ants. When a homeowner complains of
seeing black ants on porches outside, correct identification is
necessary to determine if the ants are either field ants or
carpenter ants. If field ants are involved, the lawn and
landscaped areas should be targeted for inspection to locate the
mounds and colonies of this ant.
The mounds built by field ants in lawns are often low in
profile, rarely reaching far above the top of the grass. A slow
walk across the lawn is necessary to find these mounds. Items
such as logs, firewood, bricks, debris and stones must be
overturned and inspected for colonies underneath. Mounds are
sometimes located at the base of shrubs in landscaped areas and
have also been found in thick layers of landscape mulch.
Field ants are soil nesters that construct medium-sized mounds
of about 8 to 10 inches (20 to 25 cm) in diameter in open fields
and vacant lots. Mounds can also be found in lawns surrounding
homes and other buildings. These ants will also commonly nest
under items, such as rocks, patio blocks, landscape timbers and
firewood piles. It is not uncommon to see a small amount of
displaced soil along side a flagstone of landscape timber.
Lifting the item may reveal a colony underneath.
Field ant workers forage actively and are commonly seen crawling
around on porches, patios and wood decks. Foraging trails are
loose, meaning that foragers are spaced further apart, making
the trail more difficult to detect. Once a food source is found,
numerous foragers are recruited to exploit the food.
Contributing Conditions. Where possible, items under
which this ant might live, such as stones, logs, debris, and
lumber should be removed. Firewood should be stored off the
ground and as far from the structure as possible. Leaf litter
should be removed. Further, steps should be taken to make sure
that layers of mulch in landscape beds around the structure do
not build up to more than 2 inches (5 cm) thick.
Control
Solution
| RED
IMPORT & SOUTHERN
FIRE ANT |
| |
| COMMON
NAME: |
Fire
Ants |
| SCIENTIFIC
NAME: |
Solenopsis
spp. |
| CLASS/ORDER/FAMILY: |
Insecta/Hymenoptera/Formicidae |
| METAMORPHOSIS: |
Complete |
|
INTRODUCTION.
These ants get their common name from their ability to inflict
especially painful bites and stings. The two most important
species are the southern fire ant (Solenopsis xyloni McCook)
and the red imported fire ant (Solenopsis invicta Buren).
The southern fire ant is a native species and ranges from
California to southern South Carolina to northern Florida. The
red imported fire ant is from central Brazil and is found in the
southeastern United States, from Virginia through Texas.
RECOGNITION.
Workers polymorphic, about 1/16-1/4" (1.6-6 mm) long;
queens average 1/4" (6.6 mm) long. Head and thorax
yellowish red and abdomen black; reproductives darker. Antenna
10-segmented, with 2-segmented club. Thorax lacks
spines, profile unevenly rounded. Pedicel
2-segmented. Stinger extruded in most alcohol-collected
specimens; readily inflict painful stings.
Characteristics
of the mandible and petiole (1st node of pedicel)
will separate these 2 species. The mandible of S. xyloni
has 3 distinct teeth on its inner/biting surface whereas, those
of S. invicta have 4 teeth and the petiole of S.
xyloni has a ventral tooth near the node's attachment to
the thorax whereas, S. invicta lacks such a tooth.
SIMILAR GROUPS.
(1) Fire ant (Solenopsis geminate) with ridge on lower
front margin of mesothorax having 1 or more teeth, 1st
node in profile with rear margin almost straight. (2) Little
black ant (Monomorium minimum) with antenna 12-segmented,
club 3-segmented. (3) Acrobat (Crematogaster spp.),
big-headed (Pheidole megacephala), harvester (Pogonomyrmex
spp.), and pavement (Tetramorium caespitum) ants have
spines on upper surface of thorax; in addition acrobat ants with
heart-shaped abdomen and pedicel attached to upper surface of
abdomen, big-headed ants with soldier with head very large and
3-segmented antennal club, harvester ants with underside of head
with a brush of long bristles (coarse hairs/setae called
psammophores), and pavement ants with head and thorax covered
with distinct ridges. (4) Other small dark ants have 1-segmented
pedicel.
BIOLOGY.
For the red imported fire ant, single-queen mounds usually
number 30-100/acre (0.4ha) with typically 80,000 but up to
250,000 individuals per colony. Multiqueened colonies may number
200-700/acre (0.4ha) but contain fewer individuals per colony,
and there is less fighting between the colonies. Typical mounds
are rounded, being up to 18" (48 cm) high and 24+"
(61+ cm) in diameter, each with several tunnels just under the
soil surface extending out several feet. A queen in a large
colony is capable of producing her own weight in eggs each day
or about 1,500 or more. Developmental time (egg to adult) for
workers ranges from 22-38 days. A mature colony can produce as
many as 4,500 swarmers during the year, with 6-8 mating flights
occurring between spring and fall. Mating flights usually begin
about 10 am, 1-2 days following a rain if it is warm (about 75
degrees F / 24 degrees C), sunny, and not very windy. Minor
workers live 30-60 days, intermediates (medial) 60-90 days, and
majors 90-180 days or longer. Queens live 2-6 years. Males die
shortly after mating.
Typical mounds of
the southern fire ant are flattened and irregular, covering 2-4
sq ft (0.17-0.37 sq m). Swarms occur from May through October in
the afternoon to early evening of warm days. Developmental time
can require as few as 44 days. Its biology has not been
thoroughly studied.
HABITS.
Fire ants are typically ground-nesting ants. However, the
southern fire ant will sometimes nest in the wood or masonry of
buildings, especially in areas near the soil or warmth such as
fireplace hearths. When the southern fire ant nests outside near
a house, it is usually in the vicinity of the kitchen. Outside
nests are usually situated under stones or other covering
objects, or in the soil at the base of a tree or shrub, or in
clumps of grass.
The red imported
fire ant typically nests outside. Each colony has its own
territory, and there is usually no movement between colonies.
However, they will sometimes nest in areas of exposed soil
within buildings such as bath traps. They also have the habit of
building outside nests adjacent to foundation walls. They are
commonly introduced into new areas via potted or balled shrubs
and trees.
Fire ants are
attracted to electrical junction boxes of traffic signals, air
conditioners, etc. When they mass around the electrical contact
points, they cause the equipment to malfunction. They will also
nest in gas and water meter boxes and then follow the pipes into
the building.
Fire ants prefer
food with a high protein content but will feed on almost
anything, plant or animal. The southern fire ant has been known
to remove insulation from phone and electrical wires, and to
gnaw on clothing, especially if soiled. They usually feed on
seeds, insects, young tree bark, honeydew and other sweets,
preferring oily meats and nuts.
Red imported fire
ants are particularly destructive to vegetation. Workers forage
in established trails.
CONTROL.
Fire ant control is difficult. It usually requires repeated
applications of liquid or granular residuals to eliminate the
colony. Particularly effective with a single application are
residual aerosols applied under high pressure (160 psi) with a
long injection probe.
Although baits
are slower acting, they are effective. Baits containing only a
stomach poison require several applications each season to
control newly emerging workers when the queen(s) is/was not
killed, and new colonies. Baits containing only an insect growth
regulator can provide year-long control with 1 or 2 applications
in the residential situation when followed in 7-10 days with a
liquid residual application to kill the active foragers. Newer
baits containing avermectin,, which acts as both an insect
growth regulator and slow-acting stomach poison, give good
control without liquid application.
Control
Solution
- One
node
- One
size worker: 1/32 inch (1.5 mm)
- Uneven
thorax
- 12
antennal segments, no antennal club
- Head
and thorax are dark, abdomen and legs are pale

ID Tip. This
ant has a translucent abdomen, hence the name ghost ant.
Feeding Habits. Indoors, ghost ants show a preference for
sweets. They are commonly found inside packages of candy, sugar
and similar foods in kitchen pantries.
Key Inspection Tips. These ants are very small so careful
inspection is essential. Inside: Foraging ghost ants are often
found trailing inside under the edge of carpet. When these ants
are found indoors, an attempt must be made to follow the
foraging workers back to the site where the colony is located.
Ghost ants are frequently found foraging inside kitchen cabinets
and bathroom vanities. The first cabinets to inspect are those
containing food products. Boxed and bagged items containing
sweets, especially those stored at the back of the cabinet,
should be inspected first. Ghost ants seem to have a high need
for moisture so they are commonly seen around sinks, toilets and
bathrooms. Pay attention to areas where water is available.
Ghost ants readily live inside wall voids and homeowners often
report seeing workers trailing out of electric outlet plates,
particularly in kitchens and bathrooms.
Outside: Mulch, grass and other vegetation should be pulled away
from the foundation of the building and along porches and
sidewalks. Ghost ant colonies are often found in the soil
beneath the grass next to the building's foundation and under
heavy vegetation lying against the base of tree trunks. The
exterior walls of the building around entryways, such as doors
and windows, often reveal trails of ghost ants. Ghost ants will
readily trail down the branches of trees and shrubs onto the
structure and through cracks around the eaves and soffits. These
ants will nest in the debris trapped in the crotches of trees,
in hollows in trees, at the base of palm fronds, and also in
hollowed out branches of shrubs. A screwdriver can be used to
stir up debris in the crotches of trees.
Contributing Conditions. As with most ants, moisture is a
limiting factor in the survival of ghost ants. Conditions which
result in excess moisture, such as poor foundation drainage,
water leaks, or sprinklers directed against the foundation,
should be corrected. As many cracks in the exterior walls as
possible need to be sealed. If possible, a vegetation-free
border should be installed around the base of the foundation to
make the area less attractive to ants and to make inspections of
the foundation easier. This vegetation-free border would contain
gravel or small stones and not bark chips or mulch. Mulch and
bark chips hold moisture, creating potential nesting sites for
ants. Branches of trees and shrubs which touch the structure
should be trimmed back away from the structure. Items under
which ghost ants could nest should be removed. These items
include boards, bricks, stones, logs and debris. Firewood should
be stored off the ground and as far from the structure as
possible.
Control
Solution
- One
node
- One
size of worker, 1/4 inch (7mm)
- 12
antennal segments
- Antennal
club gradually enlarges to tip
- Has
circle of hairs at tip of abdomen
- Yellow-orange
in color

ID Tip.
Workers give off a citronella or lemon-like odor when crushed.
This ant has very small eyes.
Feeding Habits. These ants feed on the honeydew gathered
from aphids and mealybugs.
Key Inspection Tips. This ant is a minor pest inside
structures except during the spring and summer when the winged
reproductives (swarmers) emerge into buildings. The
"citronella ant" is a soil-nesting ant that constructs
nests in soil under items, such as logs, rocks, patio blocks,
porches and sometimes concrete patios. This ant is often found
by termite control professionals as they dig trenches in
preparation for treating the soil next to the foundation.
Colonies are also common in open areas of soil, especially in
crawlspaces. Large colonies have been observed in the soil of
crawlspaces under houses, under concrete slabs, and along the
foundations outside buildings. The citronella ant also will nest
in rotting wood, such as logs and firewood, which has been
stored on the ground too long. It has been found living in old
termite-damaged wood that is moist. Because these ants feed
exclusively on subterranean homopterous insects (aphids and
mealybugs) and are most active at night, foragers will rarely be
seen by homeowners inside. Foraging activity occurs under the
soil along plant roots where the aphids and mealybugs are
found.
If citronella ant swarmers or workers are found inside a
building, time should not be wasted inspecting for colonies
located inside the structure. Colonies are most likely to be
found along the foundation both on the outside and on the inside
if a crawlspace is present. If the ants are nesting under a
concrete slab, soil excavated by the ants is usually present
along the sides or on top of the slab indicating the colony's
location. In addition to inspecting along the foundation, an
inspection of the entire property is necessary. Outlying
colonies can serve as sources for colonies becoming established
next to or under the foundation. Items on the ground, such as
rocks, logs, landscaping timbers, etc. should be lifted to check
underneath.
Contributing Conditions. Environmental conditions are not
as important for controlling infestations of citronella ants as
they are for other ants. However, establishing a vegetation-free
zone along the foundation of the structure may be helpful in
preventing colonies from nesting next to the foundation. Items
under which ants could nest, such as stones and logs, should be
removed. Firewood should be stored off the ground and as far
from the structure as possible. Sealing cracks in the slab
foundation can stop swarmers from entering the building.
Control
Solution
- Two
nodes
- One size
worker, 1/16 inch (2 mm)
- Uneven
thorax
- Thorax has no
spines
- 12 antennal
segments
- Club segmented
in 3 parts
- Black color

ID Tip.
The little black ant, not surprisingly, is a very small, black
ant. This ant is closely related to the Pharaoh ant and looks
just like it except for its black coloration.
Feeding Habits. The natural food of little black ants is
the honeydew produced by homopterous insects (e.g., aphids,
mealybugs, and scales) and sweet secretions produced by plants.
Indoors, little black ants feed on sweets, meats, grease, bread,
oils, cornmeal and fruit juices.
Key Inspection Tips. Within its range, the little black
ant is common in wooded areas and can be a frequent invader of
homes and other buildings. Outdoors: The little black ant nests
in the soil under items, such as rocks, logs or debris. It will
also build nests in open areas of soil in lawns and in landscape
mulch. The nests in the ground are characterized by small
craters of very fine soil. Colonies have been found under the
bark of trees, in debris trapped in the crotches of trees, in
wood damaged by termites, in firewood piles and within stacks of
bricks and stones. When inspecting for foraging little black
ants, grass, vegetation and/or mulch should be pulled away from
the foundation of the building and along driveways and
sidewalks.
Any item in contact with the soil such as logs, stones, etc.
could harbor a colony. Sprinkler heads also may be a site to
find a small colony. Little black ant colonies are most often
associated with dead wood or piles of items like bricks and
stones. Trails for workers often originate up tree trunks from
some dead limb or tree hole. In such cases, accessing the colony
may be difficult.
Inside: Little black ant colonies or individual trails can be
found in wall voids, cabinet voids, under the edge of carpets,
and in the voids of masonry, such as brick or stone veneer on
the outside of the structure.
When ants are found living indoors, an attempt should be made to
follow the foraging workers back to the site where the colony is
located. If the ants are entering and exiting from under the
wall, they may be originating from outside along the foundation
or from tree branches touching the building.
Contributing Conditions. As many cracks in the exterior
walls as possible need to be sealed. Items under which little
black ants could nest should be removed. Firewood should be
stored off the ground and as far from the structure as possible.
Tree and shrub branches should be trimmed away from the
building. Dead tree limbs should be removed.
Control
Solution

| COMMON
NAME: |
Odorous
house ant |
| SCIENTIFIC
NAME: |
Tapinoma
sessile (Say) |
| CLASS/ORDER/FAMILY: |
Insecta/Hymenoptera/Formicidae |
| METAMORPHOSIS: |
Complete |
INTRODUCTION.
The pungent, "rotten-coconutlike" odor given off when
this ant is crushed gives it its name. It is a native species
and is found throughout the United States.
RECOGNITION.
Workers monomorphic, about 1/16-1/8" (2.4-3.25 mm) long.
Body brown to black. Antenna 12-segmented, without a club.
Thorax lacks spines, profile unevenly rounded. Pedicel
1-segmented, with small node/segment hidden/concealed
from view from above by base of gaster. Gaster with anal
opening slitlike, lacking circlet of hairs. Stinger
absent. Workers emit a disagreeable, rotten, coconut-like odor.
SIMILAR
GROUPS. (1) Ghost ant (Tapinoma melanocephalum) with
head and thorax dark but abdomen and legs pale. (2) Argentine (Iridomyrmex
humilis), crazy (Paratrechina longicornis), pyramid (Conomyrma
insana), and dark field (Formica spp.) ants have node
visible, not hidden by gaster; in addition, pyramid ants with
thorax with single tooth on upper surface, field and crazy ants
with circular anal opening surrounded by circlet of hairs and
crazy ants additionally with antenna! scape (1st segment) at
least twice head length and very long legs in relation to body
size. (3) Other small dark ants have 2-segmented pedicel and/or
lack rotten coconut odor when crushed.
BIOLOGY.
Colonies may be composed of several hundred to 100,000 ants.
There are usually many queens in a colony. Developmental time
(egg to adult) is 34-83 days, varying with temperature during
summer months, and up to 6-7 months during the winter. Colonies
typically produce 4-5 generations a year. Although they probably
mate both inside and outside the nest, the first swarmers appear
from May to mid-July. The workers and queens live for several
years. Individuals from different colonies are not hostile to
one another and workers normally move along trails.
HABITS.
Inside, these ants usually construct their nests in wall voids
especially around hot water pipes and heaters, in crevices
around sinks, cupboards, etc. These ants prefer sweets but also
eat foods with high protein content and grease such as meats and
cheese.
Outside, they are
often found in the nest of larger ants, in exposed soil, but
mostly under objects. Workers feed on insects, seek honeydew and
plant secretions, and even feed on seeds. They are extremely
fond of honeydew and attend such honeydew-excreting insects as
plantlice (aphids), scale insects, mealybugs, etc. They are most
likely to enter buildings when their honeydew supply is reduced
such as during rainy weather or with leaf fall in the autumn.
When workers are
alarmed, they run around in an erratic manner with their gasters/abdomens
raised up.
CONTROL.
Location of the nest(s) is crucial and can often be accomplished
by following the trail of foraging workers back from the food
source. Use of boric acid dust in the voids of outside
ground-floor walls and infested interior walls along with
barrier treatment is effective. Baiting is often required.
Control
Solution
|

| COMMON
NAME: |
Pavement
ant |
| SCIENTIFIC
NAME: |
Tetramorium
caespitum (Linnaeus) |
| CLASS/ORDER/FAMILY: |
Insecta/Hymenoptera/Formicidae |
| METAMORPHOSIS: |
Complete |
|
INTRODUCTION.
This ant gets its name from commonly locating its nest in or
under cracks in pavement. Pavement ants were introduced from
Europe by the early colonists. They are found in most of the
eastern half of the United States and in California and
Washington.
RECOGNITION.
Workers monomorphic, about 1/16-1/8" (2.5-4 mm) long;
queens about 3/8" (8 mm) long. Body light brown to black
with paler legs and antennae. Head and thorax
furrowed/grooved with parallel lines. Antenna
12-segmented, with 3-segmented club. Thorax with
pair of small spines on upper back part, profile
unevenly rounded. Pedicel 2-segmented Stinger
present.
Swarmers can be
distinguished from other ant swarmers by the presence of fine
furrows/grooves on their head and thorax, similar to those of
the workers.
SIMILAR GROUPS.
(1) Harvester ants (Pogonomyrmex spp.) have underside of
head with a brush of long bristles (coarse hairs/setae). (2)
Acrobat ants (Crematogaster spp.) with pedicel attached
to upper surface of abdomen (gaster), gaster heart-shaped. (3)
Other small dark ants with only 1 node/segment in pedicel or if
with 2 nodes, then thorax lacks spines on upper surface.
BIOLOGY.
Very little work has been done on this ant. Colonies are
moderately large to large, averaging 3-4,000 ants and several
queens. Developmental time varies from 36 to 63 days. Winged
reproductives appear outside primarily in June and July, but may
emerge anytime inside including during the winter months.
Workers have been shown to be an intermediate host of the
poultry tapeworms Raillietina tetragona (Molin) and R.
echinobothrida (Mednin).
HABITS.
Inside, pavement ants will occasionally nest in walls, in
insulation, and under floors. The most likely place is in
ground-level masonry walls of the foundation and especially near
some heat source in the winter. They often follow pipes which
come through slabs for access to upper floors of buildings.
Outside, these
ants typically nest under stones, in cracks in pavement, and
next to buildings. They enter buildings through cracks in the
slab and walls, slab expansion joints, and the natural openings
of buildings. Although not aggressive, workers can bite and
sting.
These ants feed
on almost anything including insects, honeydew, seeds, plant
sap, and household foods such as meats, nuts, cheese, honey, and
bread, but show a preference for meats and grease. They forage
in trails, and for distances of up to 30 feet (9 m).
CONTROL.
Location of the nest(s) and its treatment with a residual is
ideal; try following ants back from the food source. Dust in the
voids of outside ground-floor walls, treatment of cracks in the
slab with a residual, and barrier treatment is the control. The
direct injection with an appropriately labeled high-pressure
aerosol (160 psi) into the entrance/exit opening in the crack or
expansion joint of a concrete floor is extremely effective.
Baiting may be necessary.
Control
Solution
- Two
nodes
- Worker
size range: 1/16 to 1/12-inch (1.5 to 2 mm)
- Uneven
shape of thorax, no spines
- 12
antennal segments
- Antennal
club has three segments

ID Tip.
Pharaoh ants are very small ants about 1/16 to 1/12 inch (1.5 to
2 mm) in length. Yellow to reddish brown coloration.
Feeding Habits. These ants have been observed feeding on
such sweets as sugar syrups, fruit juices, jellies, cakes and
fruit pies, as well as greases. Although this ant feeds on
sweets, it is believed by some to prefer fatty foods.
Key Inspection Tips. In temperate climates, such as the
United States, the Pharaoh ant does not survive outdoors year
round where cold temperatures occur. It is therefore found most
often in close association with heated buildings. It can survive
outside only in the subtropical areas of the country such as
Florida and Hawaii.
In buildings, nests are usually first located in warm, moist
areas such as the kitchen and bathrooms in a home or apartment.
Outside these ants are most often found near heating pipes and
radiators, sinks, drains and toilets. As infestations become
more severe, ants will be found in other, but less preferred,
areas of a building. Newly formed colonies generally remain in
contact with their parent colony. It is very important that a
positive identification be made that Pharaoh ants are the
infesting species. Oftentimes, it is assumed that Pharaoh ants
are involved but another species is present. Additionally,
incorrectly identifying a Pharaoh ant as another species
followed by application of residual insecticides creates a more
widespread and difficult-to-control Pharaoh ant infestation.
Due to the cryptic nesting habits of this ant, finding even one
nest site can be a timeconsuming task. The goal of an inspection
is to locate as many foraging trails as possible in order to
determine where baits should be placed. One technique which is
often used to determine where Pharaoh ants are active is through
the use of non-toxic food baits to attract workers.
After positive identification is made that a Pharaoh ant
infestation is present, food baits are placed in areas where
ants would most likely be found. These areas include window
sills, in kitchen cabinets, in bathroom vanities, along
baseboards, next to fish aquariums, on kitchen and bathroom
counters, in medicine cabinets, behind a refrigerator or stove
and inside the electric outlet boxes in the kitchen, bathrooms
and laundry room. The stove and oven provide grease and food
particles as a readily exploited food sources.
Contributing Conditions. The main factor in the success
of a Pharaoh ant management program is to eliminate as much
potential food and water as possible on which ants could feed.
Good sanitation forces the foraging workers to be more receptive
to ant baits.
Control
Solution
- Two nodes
- One size
worker, 1/32 inch (1.5 mm)
- Uneven shape
of thorax
- 10 antennal
segments
- Antennal club
has 2 segments
- No spines on
thorax
- Yellow in
color

ID Tip. These
ants are very tiny, probably the smallest ants found infesting
structures. Often confused with Pharaoh ant. The primary
difference between the two species is the thief ant has a
2-segmented antennal club while the Pharaoh ant has a
3-segmented club.
Feeding Habits. Thief ants often feed on the larvae and
food of other ants. They are also predacious on the immature
stages of many insects. They will also feed on other food found
within structures, such as dead insects and grease. They also
feed on germinating seeds and the honeydew produced by
homopterous insects (e.g., aphids, mealybugs, etc.).
Key Inspection Tips. This ant is nicknamed a
"thief" because it commonly lives near the nests of
other ants and "steals" their larvae and food to feed
its own colony. The first step when encountering tiny yellow
ants in a structure is to identify whether the ant is a thief
ant or a Pharaoh ant. The control procedures used for these two
ants vary greatly. Once correct identification of the pest ant
involved is made, an inspection can be conducted. Inside: Trails
of thief ants may be found along baseboards, on walls, in
closets, inside cabinets (particularly ones which contain food
products), around sinks and along window sills. Inspections
should be focused in rooms where the customer has seen ants. If
ants are found, an attempt should be made to follow the trail
back to the nest location. Workers forage in set trails which
can be found along baseboards, inside cabinets and closets, and
on walls. They can use electric wires to move from room to room
and have been observed exiting from behind electric wall plates.
Their trails are often in the same locations as those of Pharaoh
ants. They can easily enter packaged foods due to their small
size.
Outside: Inspections should be focused on finding possible ant
trails on walls near windows and doors. In addition, foraging
workers may be found trailing onto the building from tree and
shrub branches, which brush against the structure.
Any item in contact with the soil, such as rocks, logs and
debris, could harbor an ant colony. Nest outdoors may be located
in the soil under items such as rocks or logs and inside
decaying would found in stumps and logs.
Contributing Conditions. As many cracks in the exterior
walls as possible need to be sealed. Items under which thief
ants could nest should be removed. These items include boards,
bricks, stones, logs and debris. Firewood should be stored off
the ground and as far from the structure as possible.
Control
Solution
One node o One
size worker, 1/8 inch (3 mm) o Uneven thorax o 12 antennal
segments, no antennal club o No circle of hairs at tip of
abdomen o Body is dark, usually black. All tarsi at the end of
legs are pale yellow.

ID Tips: Node is
flattened and hidden. All tarsi at the end of legs are pale
yellow. Feeding Habits. White-footed ants are particularly fond
of sweets and, like many ants, will tend and protect homopterous
insects (aphids, mealybugs, and scales) that produce
"honeydew." Key Inspection Tips. Outside, trails of
white-footed ants will usually be quite visible on walkways,
foundations, and the sides of buildings. Once a trail of ants is
found, the trail should be followed in the direction in which
these workers are heading Any object lying on the ground, such
as lumber, stones or trash, is a potential nesting site. Piles
of any item are especially coveted by this ant (and other ants),
particularly items in shaded, damp areas. Landscape mulch should
be moved away from the building foundation and the base of trees
and shrubs to check for ant colonies. Branches of trees and
shrubs brushing against the building should be checked for
trails of foraging ants. Nests in soffits and attics are not out
of the question, especially if the attic is poorly ventilated
and humid or excess moisture is evident in the soffits. The soil
of potted plants is a potential nesting site. Where possible,
lifting potted plants off the ground or floor will reveal piles
of soil displaced by nesting ants. Inside, these ants may nest
in wall voids and in the soil of potted plants and atriums. The
workers will forage along baseboards both above and below the
edge of carpets. When this ant is observed foraging indoors, an
attempt should be made to follow the trail to the point where
the ants are entering. Contributing Conditions. If conditions
exist which result in excess moisture (e.g., sprinklers which
spray onto the foundation), they should be corrected. However,
it is nearly impossible to significantly impact an infestation
of these ants by attempting to limit moisture conditions alone.
Branches of trees and shrubs need to be pruned away from the
structure's roof and walls. Because this ant is so difficult to
control, sealing as many cracks in the exterior walls as
possible is crucial in helping to limit interior invasions. If
possible, a vegetation-free border should be installed around
the base of the foundation. This vegetation-free border should
contain gravel or small stones and NOT bark chips or mulch.
Items under which these ants could nest should be removed,
including boards, bricks, stones, and logs. Firewood should be
stored off the ground and as far from the structure as possible.
Control
Solution
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