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 PHARAOH ANT
Common
Name: Pharaoh ant
Scientific Name: Monomorium pharaonis
Introduction.
This ant’s common name
resulted from the mistaken
belief that it was one
of the plagues of Egypt
in the time of the Pharaohs.
Pharaoh ants are thought
to be native to the
African region. Pharaoh
ants are found throughout
the United States and
have been strongly implicated
in the spread of various
disease pathogens in
hospital settings.
 Recognition. The workers are 1/16
inch long and the body
is yellowish to orange,
with a dark tip at the
rear of the gaster (enlarged
part of the abdomen).
Under magnification,
the antenna is 12-segmented,
with a 3-segmented club.
The thorax profile is
unevenly rounded. The
waist (abdominal pedicel)
is 2-segmented (two
nodes) and a stinger
is present but seldom
used. Queens are about
1/8 inch long and slightly
darker in color than
workers. Queens are
produced with wings
but the wings are removed
soon after mating, Males
are about 1/16 inch
long, winged, black
in color, and possess straight antenna straight,
not elbowed. The males
are very gnat-like in
appearance.
Similar
Ants. Thief
ants (Solenopsis molesta)
are tiny and yellow-orange
like pharaoh ants but
have antennae that are
10-segmented with a
2-segmented club.
Biology. The colonies tend to
be large with workers
numbering in the thousands
to several hundred thousand.
There are usually several
hundred reproductive
females present in such
a colony. Although winged
reproductives are produced,
there are no flights
of swarmers. Rather,
mating takes place within
the nest. New nests
can be formed by “budding”
with as few as 5 workers,
10 pre-adults (larvae
and pupae), and one
queen migrating from
the original colony.
Developmental time (egg
to adult) for workers
is about 38 days at
80? F Workers live about
9 to 10 weeks, with
only up to 10% out foraging
at any given time. Queens
live 4 to 12 months,
and males die about
3 to 5 weeks after mating.
These ants are of particular
importance in hospitals
where they will enter
wounds, enter in-use
IV bottles, seek moisture
from the mouths of sleeping
infants, etc. More than
a dozen pathogenic bacteria
have been found on pharaoh
ants collected in hospitals.
 Habits. Inside, Pharaoh ants
nest in warm, humid
areas near sources of
food and or water. Nests
are usually located
in inaccessible areas
such as wall voids,
behind baseboards, in
furniture, under floors,
and between linens.
Also pharaoh ants will
nest in debris collected
on flat roofs and those
nesting inside will
venture outside onto
flat roofs in warm weather
for water and food (dead
insects). They typically
enter and exit via poorly
caulked and defective
windows, under the flashing,
and through weep holes
in brick veneer.
The workers forage widely
from the nest in search
of food and water, and
establish trails to
food and water sources.
They commonly use electrical
and telephone wires
as a highway system
to travel through walls
and between floors.
Pharaoh ants are common
problems in commercial
food handling establishments
such as hotels, grocery
stores, hospitals, and
in apartment complexes.
Outside, these ants
seem to be of little
importance as pests.
In the temperate northern
areas of the United
States, they usually
cannot survive outdoors
year round. They have
a wide preference in
food, ranging from syrups
to fruits, pies, meats
and dead insects. They
use carbohydrates primarily
for maintenance; whereas
protein is primarily
required for larval
development and egg
production by the queens.
Cultural
Control & Preparatory
Measures. A
thorough initial inspection
is crucial to determine
ant locations. Pre-baiting
with non-toxic mint-apple
jelly can help to locate
ants. Outside, an inspection
of the building perimeter,
including thresholds
and window ledges, for
possible ant activity
is helpful as well.
Quickly clean up food
(including pet food)
and beverage spills
from floors, counters,
porches and decks to
discourage foraging
by these ants indoors
and near residences/buildings.
Food items should be
stored in airtight containers,
if possible.
Do not attempt to control
pharaoh ants using over
the counter insecticide
products because this
may make the problem
worse, as mentioned
above. Nor should one
disturb or contaminate
the foraging ants or
the bait stations that
have been installed
by the technician.
Professional
Control. The
typical use of repellent
liquid or dust insecticides
(versus non-repellent
baits) actually makes
the situation worse
by causing the colony
to fracture (“bud”)
into several colonies.
Immediately after such
an application, a false
sense of control is
perceived during the
7 to 10 days it takes
for the colonies to
relocate and reorganize,
because ants are not
seen. Then the ants
resume their foraging
activity and again become
visible. This cycle
can be repeated many
times.
Baiting is usually the
only method of effective
control. For this reason,
Rottler technicians
employ multiple strategic
placements of bait stations
known to be attractive
and effective against
pharaoh ants. Baits
are located as close
as possible to where
the ants are entering/exiting
from walls, ceiling,
appliances, etc., but
such that the likelihood
of bait station disturbance
is minimal. Technicians
place baits as close
to foraging lines of
ants as possible without
disturbing them.
If the Pharaoh ant infestation
is in a multifamily
building, the only way
such an infestation
can be eliminated is
inspection and treatment
of the entire building.
Otherwise, ants will
move from non-treated
units into ant-free
units.
If the ants are nesting
in the ground on the
outside, a perimeter
barrier application
utilizing a fine granular
insecticide bait or
residual insecticide
formulation is made.
Window sills have proven
to be strategic baiting
zones
as well.
Locations
Serving the St. Louis Metropolitan area since 1956, including
Arnold, Ballwin, Chesterfield, Crestwood, Creve Coeur, Des Peres,
Fenton, Florissant, Kirkwood, Maryland Heights, Overland, St.
Charles, Webster Groves, Wentzville and surrounding areas.
In Illinois: Belleville, Collinsville, Edwardsville, Columbia,
Madison, Waterloo, O’Fallon, Granite City, Alton, St. Clair, Monroe
and surrounding areas.
Columbia & Jefferson City, MO and surrounding areas. |
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