Termite colonies

From Tropical Topics newsletter, No. 64 December 2000, produced Stella Martin at the Environmental Protection Agency. Download the PDF to read the whole issue.

How a termite colony begins

On a suitably humid night, often at the beginning of the wet season, winged termites spill out of the colonies in which they were raised. These winged termites are special. They are colony founders.

Unlike their pale, blind brothers and sisters, winged termites are fully-developed adults, dark in colour with well-developed compound eyes. Also, in contrast to the workers which raised them and the soldiers which guarded them, they are sexual beings and their job is to reproduce. Although they have two pairs of wings, they are weak fliers, and don’t move far from their home nest. Their first flight is usually their last and soon after landing they lose their wings, by breaking them off at a line of weakness at the base. However, they have other thrills in mind. Elevating their abdomens, females produce a sex-attracting hormone — and the males come flocking.

Progeny of millions

As soon as they have paired up, each couple chooses a site suitable for a new colony and dig themselves a chamber. Sealed safely inside, the honeymooners mate repeatedly and within a few days the female, now a queen, begins her lifetime job of producing eggs. She and her mate, the king, tend these first few eggs and the young which hatch from them, but their devotion to childcaring duties is a passing phase.

The young they produce are an investment in their future. When they are old enough they will devote their lives to feeding, defending and caring for their parents and subsequent generations leaving the king and queen free to pursue a long career of full-time mating and egg production.

Laying up to 3000 eggs a day from her greatly enlarged abdomen, the queen is thought to live for many years and even decades eventually building colonies which, in some cases, are inhabited by a million or more of their children.

The majority of termites which hatch from the eggs are workers while a small number (about 1-15 per cent) are soldiers. Both these types of termites are sterile. It is only after the colony has been established for several years that sexually active, winged ‘alates’—potential kings and queens—are produced and released to start new colonies.

Duties of worker termites

It is uncertain how the type of termite to emerge from an egg is determined but it seems that pheromones released by existing termites play a part. Pheromones are chemical substances which are used to communicate messages around the colony as members exchange saliva and food. If the number of soldiers in the colony drops, the level of pheromones they produce also drops and more soldiers are then created. However, if there are too many of one type of termite some are destroyed by the workers. Workers engage in a number of chores; constructing and repairing the family home, caring for eggs and younger siblings, collecting food and feeding their parents and other colony members.

Nestmates, of some species, need only twitch the antenna of a worker to be treated to the contents of its stomach. Workers are soft and vulnerable and generally hide from the light. To protect themselves, some species build special mud tubes through which to travel beyond the nest, out of sight of predators and hidden from dangerous sunlight. Other species emerge at night but some, which are pigmented to protect them from UV rays, risk foraging during the day.

Soldiers defend the colony, taking up duties wherever the nest has been attacked or is being repaired and when the winged alates are emerging from breaches. Many have strong, well-developed jaws used to bite intruders although some employ a curious snapping technique. One side of the jaw is released, under pressure, rather as we snap our fingers, to give an intruder an unexpected sideways whack. If the soldier misses, however, it may be the one to go flying! Other soldiers secrete chemicals in droplets or threads from the tip of their pointed heads.

These chemicals may be toxic or repellent or may physically entangle attacking predators. Yet other species use strong, enlarged heads, to barricade tunnels against intruders. Soldiers may also warn of an intrusion by beating their heads against a tunnel wall. The specialised mouthparts of soldiers mean that most cannot eat and must rely on the workers to feed them. While the colonies of some species are the progeny of just one queen, in other species additional termites with reproductive capacities are produced as 'stand-bys'. These termites never leave the nest. They may be produced when reproduction rates of primary queens and kings begin to fail, so they can supplement production.

This is particularly common in the nests of the more primitive species, which have smaller-bellied queens, and can result in massive colonies. The female substitutes are less productive than the primary queens, so more are needed—more than 100 were found in one mound. These reproductive termites are usually darker than workers and soldiers and may have wing buds and compound eyes.