Termites are small,
soft-bodied, social insects that feed on wood, grass, dead leaves, bark, humus,
fungi or the dung of herbivores. They are commonly known as white ants, but are
not related to true ants. There are over 2300 species of termites, and of these
about 12 species damage sound timber. Termites also recycle organic materials
and aerate the soil. They are an important part in the diet of other animals
and their activities provide hollow logs, which are used by birds and mammals. Each
termite colony may comprise more than a million insects divided into
specialized groups called castes. Each caste is physically different and
performs a particular function.
Primary
reproduction
Primary reproductive
are the king and queen that established the nest after leaving existing
colonies. In an established nest the queen may be enlarged and practically
immobile. In some species, the queen can lay 2000 to 3000 eggs per day. The
king and queen may live for 15 years and are replaced when Primary reproductive
too old to meet the needs of the colony. The king periodically fertilizes the
queen, unlike bees, wasps and ants where the queen usually mates only at the
beginning of her reproductive life.
Winged
reproduction
Winged reproductive are
also called alates (Inswa) are the future kings and queens of new nests. They
have a well developed cuticle, compound eyes, and two pairs of usually dark
brown elongated membranous wings of equal length. Alates disperse in large
numbers from mature colonies, usually in warm humid weather. They are weak
fliers and quickly land and drop their wings. The females release a scent
(pheromone) to attract a male with which to establish a nest. Only small
percentages are successful in establishing new colonies. It takes several years
of development before a nest can do significant damage. Alates are only
produced in well-established, mature nests. During their dispersal flight,
alates commonly land on the roofs of buildings and move inside. This is not a
matter for concern since they must first establish a nest in the ground.
However, alates seen emanating very close to the house suggests a nest is
nearby and a pest control operator should be contacted.
Soldiers
Soldiers are sterile males
and females; they are not involved in reproduction. Their main function is to
protect the colony. They also scout and locate new sources of food. Soldiers
have a thin, white or light brown cuticle over most of the body and a thicker,
dark brown cuticle covering the head. Soldiers are physically distinctive and
are the primary group used for species identification. Soldiers cannot feed
themselves and are dependent on the workers for their nutrition. Some soldiers
exude an acid fluid as a means of defense. This fluid can corrode metal and
will penetrate mortar and low grade concrete.
Workers
Workers are the sterile
males and females that feed the colony, rear young and repair and enlarge the
nest. They are the only caste that can chew and digest the cellulose in wood.
Workers have thin cuticles and are the most numerous caste of the colony.
Workers, soldiers and the enlarged queen are very susceptible to desiccation
owing to their thin cuticles. Thus the humidity of the nest is kept at 90 to 95
percent. When termites are forced to cross a structure that they cannot eat,
they construct mud-like shelter tubes (or galleries) which protect them against
light, desiccation and predators.
Life
cycle
The life cycle of
termites is described as "incomplete metamorphosis" with egg, nymph
and adult stages. In the nymph stage termites grow through a series of molts.
The life cycle of true ants is known as "complete metamorphosis";
with egg, larvae, pupa and adult stages.
Termites
are the most important soil fauna in the semi-arid
tropics. They are found in wide range of terrestrial environments and are
distributed throughout the tropical, subtropical and temperate regions of the
world. Some termite species extend their range of occurrence to the relatively
cool zones of temperate regions. Termites are useful recyclers of organic
compounds (i.e., cellulose) because their bio–turbating activities accelerate
the soil rehabilitation process by breaking up of surface crusts, reducing soil
compaction, increasing soil porosity, improving water infiltration into the
soil and enhancing water holding capacity of the soil, thereby reducing
surface runoff. The
pedological effects of termites are manifested in the physical modification of
the soil profile through selecting, transporting and rearranging soil
particles. Termites seem to either increase infiltration by improving soil
structure and porosity, or to decrease infiltration by producing compact
surfaces which assist runoff and erosion. Other effects involve the chemical
alteration of the soil profile by termites collecting and transporting live and
dead animal and plant materials to their nest structures, and by the additions
of secretions and excreta in nest construction. The majority of termites
probably increase carbon and nutrient levels, especially nitrogen, phosphorus
and potassium, as well as exchangeable magnesium and calcium. The extent of the
increases depends greatly on the type of mound construction and the degree to
which organic material is incorporated.
Relationship with vegetation
Moreover,
vegetation and termites
have a closer relationship that in most cases they co-exist and this
relationship promotes interdependence among living organisms and different
variety of species. The role of biodiversity in providing ecosystem services is
actively debated in ecology. However, many other species are critical for
ecosystem functioning and provide “insurance” against disturbance,
environmental change, and the decline of the dominant species. Different
species capture different resources, leading to greater efficiency and higher
productivity. The diversity of functional groups contributes to the smooth
functioning of an ecosystem, and any disturbance on the diversity of termite
will have a great impact on the environment. However,
termites in their natural habitat disrupt the ecological system and/or caused
significant economic damage. In many parts of the world scientists have studied
termites and come up with ways in which they can prevent termites’ attacks
against infrastructure, crops, wooden rail slippers and wooden poles. Like in
other parts of the worlds, studies and experiments have been conducted in
Mwekera National Forest of Zambia to find ways in which they can prevent
termites’ attack. In 1950’s experiments on the
effectiveness of preservatives against termites were done. Even though all
these efforts have been done scientists carrying out such studies have little
knowledge on the diversity and behavior of termites.
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