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Overview |
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"Termites are well known both for their destruction of human property and for their construction of huge
mounds or 'termitaria' which allow them to have a great degree of control over the temperature and
humidity of the environment they live in. They are common in the tropics and occur in most warm habitats
as well. They are often called 'white ants' because the majority of them are white and small and live in large
colonies much like ants. They are not actually closely related to the ants at all but are closely related to the
Cockroaches. The most primitve Termite known is Mastotermes darwiniensis from northern Australia.
Mastotermes darwiniensis lives in the soil in nests consisting of up to 1 000 000 individuals, has very
catholic tastes (will eat almost anything) and has been described as the most destructive insect in Northern
Australia, its workers a very similar to nymphs of the Cockroach Cryptocercus punctulatus. Some of the
most advanced species are the Macrotermtinae which grow fungi for food (Termitomyces) inside their
nests on piles of faecal pellets. The oldest known Termites are fossils of Cretotermes carpenteri from the
Cretaceous. The sterile workers live for 2-4 years while primary sexuals live for at least 20 and perhaps
50 years."-- (Earth Life)
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Identification |
- Primary Reproductives
These are generally darker in colour than the other members of the nest and have
two pairs of wings which are voluntarily shed after they have come to ground from
the nuptial flight before they mate. After mating they are called the King and Queen.
The Queens abdomen becomes enlarged with time, extemely so in the more advanced
families such as the 'Termitidae' when she is referred to as being 'physogastric'
and may have an abdomen 9 cms long At her peak she will be laying an egg every 3 seconds
or 30 000 a day in some species and she will lay 10's of millions of eggs during
her life. The 'Primary Sexuals' have a more developed brain and they suppress the
sexual development of the rest of the nest through hormones they secrete which are
passed from one individual of the nest to another by anal liguid exchange
or 'oral anal tropholaxis'. The Queen once the nest is well established no longer
eats wood but is fed on the saliva of the workers and or on the fungi in the Macrotermitinae.
- Suplementary Reproductives
These normally have their wings reduced to wing buds in the lower termites but
look like ordinary dealate (wingless) primary reproductives in the higher forms.
They generally arise after the nest has lost its primary reproductives and tend
to be much more common in the lower termites than in the highly evolved forms.
- Sterile Workers
The workers build and maintain the nest, conduct all the foraging and care for
the eggs and young as well as caring for the Queen. The simplest termite nests
(those made by the Kalotermitidae and Termopsidae) have no true workers, instead
the role of worker is performed by various nyphal instars sometimes referred to
as 'pseudergates' apart from this the workers normally make up most of the individuals
in the nest though actually male and female they have greatly reduced genitalia
and are functionally sterile. In some species such as Macrotermes estherae and
Nasutitermes costalis the workers are dimorphic having large and small forms, in
the Macrotermitinae the larger workers are the males and the smaller workers the females.
- Soldiers
These are stucturally specialised defenders of the nest and occur in nearly
all genera. In most cases they are of either sex but in the more advanced
Termitidae soldiers may be limited to one sex, males in the Nasutitermitinae
and females in the Macrotermitinae and Termitinae. They have large sclerotized
heads and come in four main types or forms.
- Mandibulate soldiers--this is the commonest form, they have large mandibles and extremely
muscled heads, the mandibles are often twisted and asymetric.
- Nasute soldiers--these have vestigial mandibles, instead of the large mandibles
they have a long frontal rostrum through which they can spit a sticky solution
produced by their 'frontal gland', they occur only in the Nasutiterminae.
- Nasutoid soldiers--these are found among the Rhinotermtidae and have mandibles of
various sizes as well as a snout like structure through which they can spit saliva
and a sticky solution secreted by the frontal gland.
- Phragmotic soldiers--these are found in the primitive Kalotermitidae and have a
strongly sclerotized head that is used to block the entrance to the nest when
it is under attack.-- (Earth Life)
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Phylogeny |
| Taxonomic Category
| Scientific Name
| Common Name
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| Phylum
| Arthropoda
| Arthropods
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| Class
| Insecta
| Insects
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| Order
| Isoptera
| Termites
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Photographs |
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Geographic distribution |
(N.C. State University Entomology Dept.)
Extremely common in tropical and subtropical climates. Generally less abundant in temperate regions.
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| North America
| Worldwide
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| Number of Families
| 4
| 7
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| Number of Species
| 44
| ~2300
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Natural history |
- Life Cycle
The eggs are normally laid singly but in the primitve Mastotermes the eggs are laid in double rows of
16 to 24 eggs glued together by a gelatinous secretion. Incubation takes from 24 to 90 days and the
eggs overwinter in cooler climes. There are normally seven nymphal instars in established colonies but the
number varies according to a number of parameters such as temperature, age of colony, size of colony
and relative humidity.
Colony foundation is either by emission of swarms of sexuals, and/or budding (as in Reticulitermes
lucifugus when the farthest outreaches of the colony develop secondary sexuals because of dilution of
the inhibitory hormones). Swarms usually occur on hot still dry days, the sexuals tend to be weak fliers and
500 metres is a good flight, the swarm breaks up as the sexuals spread out. The sexuals cast off their
wings as soon as they hit the ground. The females (Queens to be) then either stand still and emit a
pheromone to attrack males (Kings) or run around all over the place until they meet one. Courtship
involves the male making some advances towards the female who strikes at him with her head this is
followed by mutual antennal caressing and then followed by the male making more advances and the
female striking at him with her head again followed by more mutual antennal caressing, this cycle may go
round 4 or 5 times before the female makes up her mind whether or not to accept the male. If she does
she runs away with him in close contact behind her this is called 'tandem running'. When they find a place to
mate the King and Queen become very repelled by light and attracted by wood, when they find a
suitable piece they take turns excavating a tunnel with a nuptial chamber at the end then seal themselves
inside and begin making the nest.
At first the Queen lays about five eggs which are looked after by her and the King when these hatch
they are at first fed by regurgitation by the Queen but are soon munching wood and thus enlarging the
nest. After 2 years the new nest may still contain as little as 10 workers and one soldier, soldiers take
about a year to mature. After a few more years the nest begins to release sexuals.
- Feeding
Termites feed primarily on wood which contains a high proportion of cellulose. The lower Termites
don't possess the enzymes to break down the cellulose themselves, instead they live in a mutualistic
relationship with one or more protozoan flagellates which live inside the Termites guts and digest the
cellulose in the wood fibres ingested by the Termites. The Protozoa get a stable environment and a
constant supply of food and the Termites are believed to get acetic acid and other simple organic acids
which they can metabolise. The Termites loose their intestinal flora every time they moult and have to
reinoculate themselves from the anal secretion another of member of the nest (proctodeal feeding).
The higher Termites (Termitidae) do not possess these protozoans but they do possess anaerobic
(living only in the absence of oxygen) bacteria in their guts instead Though it is believed they do not play
as important a role in cellulose digestion as the Protozoa do in the lower Termites, and it may be that the
Termitidae can secrete cellulase (the enzyme that breaks down cellulose) themselves. A number of
species of the higher Termites in the Hodotermitidae forage outside the nest, Odontotermes latericus in
South Africa collects green grass and seeds which it stores in granaries inside its nest. Nasutitermes
triodiae in Australia store dry grass in special chambers in the walls of their termitaria, while
Hospitalitermes monocerus the Black Termite of Ceylon sends out large foraging columns of workers
which are guarded by soldiers to collect the lichens on which it feeds its young. Some species (i.e.the
Macrotermtinae (Termitidae) grow fungi (Termitomyces sp.) inside their nests on piles of faecal pellets, the
fungus is used for food and each termite species has its own species of fungi, these fungi are not found
anywhere outside of the termites nests.
- Economic Importance:
Termites are an important part of the community of decomposers. They are abundant in
tropical and subtropical environments where they help break down and recycle up to one
third of the annual production of dead wood. Termites become economic pests when their
appetite for wood and wood products extends to human homes, building materials,
forests, and other commercial products. In the United States alone, annual losses due to
termite infestations are estimated at more than 800 million dollars."-- (Earth Life)
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How to encounter |
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Most primitive Termites live in dead wood, their homes are just the tunnels created while they are
acquiring food, and their nests have no real structure. Species of Rhinotermes, Reticulotermes and
Captotermes are what is known as 'Subterranean Termites' in America and have their nest below ground
but attack above ground wooden structures. In order to avoid the dryness of the open air they construct
covered walkways to allow themselves access to otherwise unreachable above ground wood. The
largest and most complex termitaria are built by the more advanced Termitidae in Africa and Australia.
These termitaria are built of either soil excavated in course of digging underground tunnels or from soil and
sand collected on the surface mixed with saliva and faeces. Nasutitermes triodiae of Northern Australia
builds huge termitaria up to 8 metres in height while another Australian Termite Omitermes meridionalis is
known as the Compass Termite because it builds its 3 metre high termitaria with one long axis and one
short axis, the long axis always runs North/South and the short axis East/West. The result of this is that the
termitaria has a large surface area facing the sun in the morning and the afternoon and very small surface
area recieving the sun in the middle of the day thus helping produce a steady temperature for the longest
possible time. Other Termites nest in the ground and feed on plant roots and and leaf litter while still others
build rounded nests in trees that look a bit like the nest of Vespid wasps."--
(Earth Life)
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Links to other sites |
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References |
- Howse, P.E. (1970), Termites: a study in social behaviour London, 150pp.
- Kofoid, C.A., et al. (1934) Termites and Termite control, Univ. Calif. Press, Berkely 734pp
- Lee, K.E. and Wood, T.G. (1971), Termites and Soils, Academic Press, London and New York,252pp
- Ratcliffe, F.N., Gay, F. J., and Greaves, T. (1952) Australian Termites. The Biology, Recognition and
Economic Importance of the Common Species. C.S.I.R.O., Melbourne, 124pp.
and Partig, Liepzig, 309pp
- Wilson, E.O. (1971) The Insect Societies Harvad University Press, Cambridge, Mass. 548pp
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Acknowledgements |
- This page written by Blythe Lang, Ecology major, University of Georgia, Athens Ga.
- Thanks to Sabina Gupta, Denise Lim, and Dr. John Pickering
for technical and web support in developing this page.
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