New Jersey termites in NJ

Introduction

Subterranean termites are the single greatest economic
pest in the United States. These termites cause billions
of dollars in damage each year to homes, historical
structures, and commercial buildings. In addition to
buildings, termites also consume valuable books, doc-
uments and photographs. Subterranean termites have
existed for over 55 million years and are extremely
good at what they do. A great deal of their success can
be attributed to their cooperative behavior.
Subterranean termites are social insects. This means
that they live in family groups called colonies. Social
insects are different from other insects (grasshoppers,
cockroaches, or beetles) because each termite in the
colony performs a specific job that benefits the colony
as a whole. Most other insects work only for them-
selves. For example, each individual grasshopper will
feed and reproduce itself independently of its siblings.
In the termite colony an entire group or caste of ter-
mites is responsible for feeding their parents and sib-
lings, while another caste is responsible for
reproduction. Because of this division of labor, the
colony of individuals functions as a single animal. The
following is a description of how a subterranean termite
colony becomes established and how the different castes
interact and communicate as the colony grows.

Colony Establishment

During the daylight hours of the spring months
(March-May in Virginia) homeowners may begin to
see winged termites emerge in large numbers inside
their home or from the soil outside. These are the sub-
terranean termite swarmers. The swarmers are new ter-
mite kings and queens that must leave their parent
colony in order to mate and establish new colonies of
their own.

The termite swarmers pair up during their flight then
land and search for a place to begin a family. Their
wings break off shortly after landing and the new king
and queen start their colony by excavating a small
chamber in a crevice or plot of soft soil. When the
chamber is large enough, they crawl inside, seal the
opening and mate. From this point on, they will spend
the rest of their lives underground. The queen lays her
first batch of (6-12) eggs within a few days or weeks of
mating. Initially, the king and queen tend the young
termites. However, as the queenÕs egg laying capacity
increases, the older offspring begin to tend their
younger siblings. The colony will now continue to
grow with increasing numbers of termites being pro-
duced each year. The parental king and queen have the
longest life span in the colony. They often survive for
a decade or longer and can produce huge colonies with
thousands of offspring.

The subterranean termite most commonly found in
Virginia is the Eastern Subterranean termite,
Reticultermes flavipes. Mature colonies (6-7 years old)
of R. flavipes in Virginia have been estimated to con-
tain more than 60,000 workers. These large subter-
ranean termite colonies often become decentralized
over time and occupy multiple nesting sites intercon-
nected by a network of underground tunnels.

VIRGINIA POLYTECHNIC INSTITUTE

AND STATE UNIVERSITY

VIRGINIA STATE UNIVERSITY

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PUBLICATION 444-502W

2001

Entomology

Subterranean Termite Biology and Behavior

Dini M. Miller*

Swarmer with workers

*Assistant Professor, Entomology, Virginia Tech

Subterranean Termite Castes

Primary Reproductives

As described above, mature subterranean colonies, at
certain times of the year, will produce large numbers of
winged swarmers or ÒalatesÓ that will eventually
become king and queen termites. These royal termites
are dark-colored and are the only caste with functional
eyes. The swarmers lose their wings after a short flight
where they select a mate. The new king termite remains
virtually unchanged after losing his wings. However,
as the new queen begins to produce eggs her abdomen
grows larger with the development of her ovaries. As
she stretches, the segments of her body pull farther
apart showing the white membranes between the seg-
ments of her abdomen. This gives the queen a striped
appearance. The eastern subterranean termite queen
will stretch until she is about 14.5 mm in length. At
this point she is an egg laying machine, producing over
500 offspring a year.

Secondary Reproductives

The termite colony originates from a single pair of
reproductive swarmer termites, the king and queen.
However, if the king or queen should die, other indi-
viduals within the colony will start to develop func-
tional reproductive organs to take their place. These
individuals are called secondary reproductives.
Secondary reproductives are light in color but they are
larger than workers and never develop wings. In
mature colonies a secondary reproductive caste can
develop even though there is still a producing queen
present. When this happens the secondary reproduc-
tive caste members will produce the majority of the
eggs, causing the colony to grow at a much faster rate.
Although no individual secondary reproductive can
produce as many eggs as the queen, several hundred of
them may exist in a single colony thus producing thou-
sands of eggs. Secondary reproductives may also
develop in satellite nests where a group of workers

have become separated from the parent colony. This
splitting or budding of the nest expands the original
colonyÕs foraging territory.

Worker Caste

Subterranean termite workers are the caste found in
infested wood. As in other termites species, the work-
ers are responsible for all of the labor in the colony.
They care for the young, repair the nest, build foraging
tunnels, locate food, feed and groom the other castes
and each other. The youngest termite workers perform
the tasks inside the colony like feeding, grooming and
caring for the young, while the older more expendable
workers take on the hazardous jobs of foraging and
nest building. The termite workers are both male and
female but they are functionally sterile. They are
milky white in color and have no wings or eyes. The
body of the termite worker is soft, but its mouthparts
are very hard and adapted for chewing wood.

Soldier Caste

Subterranean termite soldiers are the defenders of the
colony. They protect the colony against marauding
ants and foreign termites. When foraging tubes or gal-

Queen

Worker

Soldier

leries are broken into the soldiers congregate around
the break to stand guard against invaders. Soldiers are
similar to the termite workers in that they are blind,
soft-bodied and wingless. However, the soldiers have
an enlarged, hard, yellowish-brown head which has
been modified for defense. The head has a pair of very
large mandibles or jaws that are made to puncture, slice
and kill enemies (primarily ants). However, the large
mandibles prevent the soldiers from feeding them-
selves, so they must rely on the workers for food.

Subterranean Termite Behavior

It is not known exactly how subterranean termites
locate sources of food. It is thought that the termites
forage by digging a network of tunnels and come in
contact with food sources in the process. The foraging
range of a single termite colony is difficult to predict.
Some larger colonies may forage over areas the size of
a football field. However, depending on the season or
weather, they may not forage over their entire range at
all times. Also, several smaller colonies may cover a
greater foraging distance than one large colony.

Foraging termites produce a variety of chemicals called
pheromones that influence their behavior. These
pheromones are basically odors that send messages to
other termites in the colony. While tunneling under-
ground, the foraging termites lay down a trail of
pheromone which they secrete from glands on their
abdomen. When a food source is located, the odor trail
is intensified to recruit other termites to the feeding
site. However, the intensity of the recruitment effort
(odor trail) is influenced by soil temperature, moisture
and compaction as well as the size and quality of the
food source.

Subterranean termites also forage above ground for
sources of cellulosic food like wood in homes and
other structures. In order to protect themselves from
predation by ants and maintain their connection to the
soil while searching for food above ground, termites
build long tubes out of mud and fecal material. These
mud tubes are called exploratory tubes. Termite
exploratory tubes are very easy to see and are one of
the best ways to identify a potential termite infestation.
Once a source of wood has been located, the termites
establish more permanent utility or working tubes.
The utility tubes are highways running from the under-
ground termite galleries directly to the food source.
Utility tubes can cover long distances over the founda-
tion of a building or along exterior walls to reach the
wood inside. Sometimes subterranean termites build
another tube that runs from the structural wood back
down to the ground. These tubes are called drop or
suspended tubes. Drop tubes are often lighter in color
than the utility tubes because they contain more of the
wood fiber taken from the structure. Subterranean ter-
mites construct a fourth type of mud tube in addition to
those that facilitate foraging. These are called swarm-
ing tubes. Swarming tubes are built seasonally extend-
ing only 4-8 inches above ground. These tubes provide
the exit port for winged swarmers leaving the colony.

Moisture Needs

Subterranean termites are constantly at risk of drying
out; this is why they must live in the soil. Soil has the
capacity to hold water for a long period of time and
keep the colony moist. When termites forage above
ground, they must maintain their connection to the soil
so that the workers and soldiers can return periodically
to replenish their body moisture. The mud tubes pro-
vide the termites with this soil connection. If a tube
becomes damaged, the worker termites will labor des-
perately to repair it. If the tube is beyond repair, the
termites located above ground will often die of dehy-
dration. However, on some occasions subterranean ter-
mite colonies do become established above ground.
These above ground infestations are almost exclusive-

Utility tubes

Swarm tubes

ly found in structures with chronic moisture problems.
Chronic problems include flat roofs where dead leaves
and moisture have been allowed to accumulate, leaking
pipes or areas with no ventilation. In such cases the
colony can survive above ground indefinitely.

Nutrition and Feeding

Although subterranean termites can chew through and
damage many materials, they can only obtain nutrition
from cellulose. However, subterranean termites cannot
digest cellulose on their own. In order to digest wood,
subterranean termites have large numbers of microor-
ganisms in their gut that convert the wood fiber into
usable nutrients. If there were no microorganisms in
the gut, the termite could eat constantly but still die of
starvation. In the colony most food is shared mouth to
mouth (a process called trophallaxis). Foraging work-
er termites feed directly on wood or other cellulose
material then store the food in their gut. They then
return to the nest and feed the immature termites, sol-
diers, and reproductives.

Immature termites are unique in their nutritional needs
because like all juvenile insects they must periodically
shed their skin (exoskeleton) in order to grow (molt-
ing). When they do this they also shed the lining of
their hindgut where the wood-digesting microorgan-
isms live. After molting the termites no longer have
their microorganisms and are unable to digest food. In
order to replenish their microorganism supply, the
young termites feed on fluids (which contain the
microorganisms) excreted from the hindgut of older

termites. This delicious practice of feeding from a nest
mateÕs anus is called proctodeal feeding. Although it
may sound disgusting, proctodeal feeding is essential
for the survival of the termite colony.

Swarming Behavior

Swarming is the termite method of dispersal and estab-
lishing new colonies. Subterranean swarmers emerge
from the colonies at certain times of the year when con-
ditions are suitable. Peak swarming season for the sub-
terranean termites in Virginia is from March through
June. The eastern subterranean termite, R. flavipes,
usually swarms in the spring (March-May) during the
daylight hours on warm days following a rain.
Subterranean termite swarmers are attracted to light so
if they emerge indoors they will be seen flying to win-
dowsills and open doors. Usually, termite swarming
either indoors or outside is the first indication to home-
owners that they have a subterranean termite infesta-
tion.

References:

Potter, M. F. Termites, pp. 232-333. In S. A Hedges

and D. Moreland [eds.], Mallis Handbook of Pest
Control, eighth edition. Mallis Handbook and
Technical Training Company. 1997.

Light, S. F. The constitution and development of the

termite colony. In C.A. Kofoid [ed.], Termites and
Termite Control, second edition. University of cal-
ifornia press, Berkeley, CA. 1946.

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