Latin
Name: Genera Kalotermes & Incisitermes
Appearance: Larger than subterranean termites, up to ½
inch long; no worker caste in the colony.
There
are three common species of drywood termites found in Wisconsin
(Incisitermies snyderi, Cryptotermes brevis, and Incisitermes minor).
You can identify the species by looking at certain features of either
the reproductives (swarmers) or solider termites.
Habit:
Create colonies in wood, with no connection to the ground necessary;
often found in attic wood; need very little moisture.
If found
within the structure, it is almost sure sign that they are in the
structural timbers of the building. If they are found outdoor, they
may have come either from within the structure or from nearby timber
of brush.
Because
drywood termites live within the wood, they produce fecal pellets.
During an inspection, piles of fecal pellets near the infested wood
will be found. (The pellets are generally the color of the wood that
they have been feeding on and are about 1/32 inches long. Under modest
magnification, long dimples or flutes down each surface will be visable.
The pellets tend to be blunt at one end and pointed at the other.)
Damage
to wood, though seldom apparent, definitely indicates a past or present
infestation of drywood termites. These termites will consume both
the harder summerwood and the soft springwood of timbers. This leaves
a smooth sculptured appearance to their galleries (fecal pellets will
also be present in the galleries).
Diet:
Wood and occasionally other cellulose material.
Reproduction: Nymphs pass through seven instars before reaching
adulthood; sexual forms eventually swarm to form new colony.
Other: Cause serious damage to structures, often long before
they are discovered; piles of sawdust-like pellets are a distinct
sign of infestation; not as widespread as subterranean termite; colonies
may contain up to 2,700 members.
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Subterranean Termites
Latin Name: Order Isoptera
Appearance: Subterranean termites are social insects that live
in nests or colonies in the soil. They contain three forms or castes:
reproductives, workers (pseudergates) and soldiers. Individuals of
each caste have several stages: the egg; the larva that develops into
a pseudergate and eventually into a brachypterous nymph or soldier;
and the adult. There are three forms of adult reproductive termites
including primary, secondary and tertiary.
Reproductive
males and females can be winged (primary) or wingless (secondary or
tertiary). Females of each can lay eggs and produce offspring. The
bodies of winged primary reproductives, also called swarmers or alates,
vary by species from coal black to pale yellow-brown.
Wings may be pale or smokey gray to brown and have distinct vein patterns
used in identification. Reticulitermes swarmer termites are about
1/4 to 3/8 inch long.
Secondary
and tertiary reproductives live within the colony and are white
to cream-colored. These termites form a backup for the primary
queen and may replace her if she is injured or dies. These termites
mate within the colony and lay viable eggs. If supplementary reproductives
and worker termites become isolated from the main colony, they can
establish a new sub-colony.
Termite
workers (psuedergates) make up the largest number of individuals within
a colony and do all the work. They are wingless, white to creamy
white and 1/4 to 3/8 inch long. They forage for food, feed the
other castes, groom the queen and maintain and build tunnels and shelter
tubes. Their mouthparts are very hard and adapted for chewing through
wood or other cellulose materials. The worker caste is responsible
for the damage that makes termites an economically important problem.
Soldiers
resemble workers in color and general appearance, except they have
well-developed brownish heads with strong mandibles or jaws.
Soldiers defend the colony against invaders, primarily ants and other
termites. They cannot forage for food or feed themsleves, and they
depend on the workers to care for them.
Ants
and termites often swarm at about the same time of year but control
measures for each differ greatly. It is therefore, important to be
able to distinguish between swarming termites and ants.
Habit: After 2 to 4 years a subterranean termite colony is
mature and produces "swarmers" (winges primary reproductives).
Termite swarmers leave the colony in large numbers during the spring
and early summer. Environmental factors such as heat, light, and moisture
trigger the emergence of swarmers, with each species having its own
set of requirements. The number of swarmers produced is proportional
to the age and size of the colony.
Both
male and female swarmers fly from the colony and travel short distances.
Termites are weak fliers and must rely on wind currents to carry them
to new habitats. Only a small percentage of swarmers survive to develop
colonies; most fall prey to birds, toads, insects and other predators,
and many die from dehydration or injury.
During
the swarming process, males (kings) and females (queens) pair off
using pheromones. Successful reproductive pairs land, lose their wings
and seek cover under rocks or other moist materials. A pair will make
a very small nest before mating. Initially, the new queen termites
lays only a few eggs. The male remains with the female and helps care
for developing eggs and the larva that hatch.
Eggs
are not deposited continuously. In fact, only a few hundred are deposited
during the first year. As the young queen grows larger, she lays more
eggs. The king and queen care for the young larvae that hatch from
the eggs because they cannot care for themselves. The larvae then
molt into psudergate workers, which in turn, can ,molt into presoldiers
or brachypterous nymphs (with wing pads). These nymphs will eventually
molt to become primary reproductives. The colony stablizes when the
queen reaches her maximum egg production. If the queen dies, supplemental
reproductives take over the queen's duties.
The maximum
size of a termite colony depends on location, food availability and
environmental conditions, especially temperature and moisture. Some
colonies remain small; others contain up to several thousand individuals.
New colonies form when groups of termites become isolated from the
main colony and establish sub-colonies. This is called "colony
splitting" or "budding." These sub-colonies may exist
independently or reunite with the main colony.
Termites
are attracted to certain odors of wood-decaying fungi that make the
wood more palatable and easier to penetrate. In some instances, the
fungi provide a source of nitrogen in the termite diet.
Moisture
is important to subterranean termites as they have very little resistance
to dehydration. To survive, termites must maintain contact with the
soil (their primary source of moisture) or other above-ground moisture
sources, such as defective plumbing, leaky roofs, leaks from air conditioning
condensers or poorly maintained gutters.
Subterranean
termites also must protect themselves from temperature extremes and
attack by ants and other insects. Termites that forage for food above
ground protect themselves with shelter tubes or "mud tubes".
Worker termites build shelter tubes from particles of soil or wood
and bits of debris held together by salivary and fecal secretions.
Mud tubes may be thinly constructed or can be large with thick walls
to accommodate many termites moving vertically between the soil and
their food source.
Subterranean
termites also transport moist soil into the structures they infest.
The presence of shelter tubes and mud within galleries is used to
identify termite damaged wood. Shelter tubes are often used to bridge
across masonry or other objects, allowing termites access to a food
source (wood) above ground. Inspecting of structures for termite damage
may identify these tubes which indicate an ongoing infestation.
Diet:
Subterranean termites get their nutrition from wood and other material
containing cellulose. Paper, cotton, burlap or other plant products
often are actively consumed by termites. Sometimes termites will even
tunnel into the dead heartwood or pith of living plants. Most species
of subterranean termites cannot digest cellulose directly and depend
on single celled protozoans and bacteria living in their hindguts
to help digest the cellulose. Digested cellulose is then shared with
the developing larvae, other workers, soldiers and reproductives.
Reproduction: Different rates of growth from egg stage to adult
depending on individual species; one queen per colony, which can lay
tens of thousands of eggs in its lifetime, but most eggs are laid
by supplementary reproductives in an established colony.
Other: Subterranean termites are the most destructive insect
pests of wood in the United States. They cause billions of dollars
in damage each year and have a negative impact on a family's most
valuable possession - the home. Subterranean termites cause 95% of
all termite damage in North America. Colonies can contain up to 1
million members.
(In nature,
subterranean termites are beneficial because they break down cellulose
into usable nutrients. The biomass resulting from this process is
recycled to the soil as humus. Subterranean termies are, therefore,
considered important to our ecosystem.)
