Isoptera (termites, white ants) 1, 2

Fast facts about Isoptera termites)

  • Mainly tropical, 2,600 plus species world wide, over 1000 species in Africa, 50 in North America, and only 10 species native to Europe.
  • in the tropical rainforest there can be more than 1,000,000 termites in a hectare.
  • Social insects with different castes.
  • Colony size from thousands to millions.
  • Hemimetabolous.
  • Most less than 20 mm long, but queens can reach 150 mm long.
  • Often called "social cockroaches".
  • Descended from wood-eating cockroaches.
  • Fossil record goes back as far as the Cretaceous.
  • Castes contain both males and females.
  • Most eat wood, some eat grass and fungi.
  • Soldiers and reproductives are fed partly digested food by workers.
  • Workers also produce partially digested faecal pellets containing the bacteria which break down the tough cellulose of plant cells.
  • They have short antennae.
  • Only the king and queen have wings, and these break off after the nuptial flight.
  • These wings are longer then their entire body length.
  • Both rear and front wings are similar (see drawing below), Isoptera in Greek = equal wings.
  • Compound eyes are present in reproductives, but may be reduced or absent in the workers.
  • Most have soft, pale-coloured bodies with short cerci.
  • Most species have biting mouthparts.

Similarities between termites and social Hymenoptera.

Differences between termites and social Hymenoptera.

Termes bellicosus, termite, sexual with wings

Above is a reproductive of Termes bellicosus in the Termitidae family. After mating the king and queen construct a nuptial chamber. This is the start of the termite nest. For photographs of the different types of nest visit page 2.

The mass release of king and queen termites from the nests usually occurs in the late afternoon or early evening, often when the ground has been softened by rain. The air is filled with insects that look as if their wings are too large for them and their flight is weak.

In the eighties I lived in rural Japan and used to watch them as I returned home from work on the train in the evening. When we stopped at small country stations the doors were left open (no air-conditioning in those days), the light would attract the termites and in they would flood. The smooth floor confused them and in an effort to rid themselves of their wings, which extended beyond their abdomen, they would try to back into the nearest obstacle; this was usually the metal rail going from floor to ceiling. The floor would be covered in wings, and if the termites were in luck they would be blown out at the next station and not have to carry on to the concrete covered terminus.

For most species, in time the nuptial chamber also becomes a prison. It is enlarged by the workers as the queen grows, but the tunnels leading off the nuptial chamber are not big enough for the queen to pass through. Some African and Australian species construct huge mounds and towers reaching as high as seven metres.

Amitermes atlanticus, king, queen, worker, soldier

Termite king and queen

The king and queen can live as long as 50 years. They mate frequently in the nuptial chamber. The queen can grow to be as long as 10 cm or more, see the Termes flavipes queen below. If the king or queen dies the workers simply rear a new one.

Termes flavipes queen, termite queen

Termite soldiers

Soldiers tend to have large heads. Some have large jaws, and others have a nozzle through which they can squirt poisonous, repellent or sticky liquids depending on species, see the Nasutitermes sp. soldier below.

Nasuitermes sodlier

In some species the soldiers have defensive saliva; there are 2 types: 1) the saliva is converted as it reaches the air into a rubbery substance that entangles small predators 2) a mix of saliva that forms a resin that again entangles small predators such as ants.

Most soldiers lack functional eyes. It is thought that soldiers and workers could live for up to ten years.

Foraging termites

Foraging termites follow trails marked by pheromones laid by their nest mates leading from the nest to the food source. However the trail does not provide information about direction, so a termite relocating a trail it has left or lost may not know whether it needs to go left or right. It is thought that the Earth's magnetic field provides this clue, as has been found with the blind grass harvesting termite, Trinervitermes geminatus.

Regulating termite caste numbers

Workers produce a "worker substance" pheromone, and soldiers produce a "soldier substance" pheromone. If the level of either pheromone falls below the appropriate level more individuals of the appropriate caste are produced in the next generation.

Thoughts on the origin of social behaviour in termites.

Termites in the UK

In 1994 a Reticulitermes grassei colony was found in a house in North Devon. The colony was eradicated, or so it was thought, but 10 years later the same species was found in the area.

Some primal termite knocked on wood
Tasted it, and found it good
And that is why your Cousin May
Fell through the parlour floor today.
Ogden Nash

Related pages