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Civilisation: how social insects took life to a new level of sophistication

Sunday 08 February 2009 01:00 GMT
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(Getty)

At about the same time that flowers first bloomed (at about 23:15 on our 24-hour clock) we also see the first signs of civilisation.

Not human civilisations these, but insects in the form of wasps and their descendants, bees and ants. There were also termites, a different branch of life altogether, related to beetles. From these creatures new, more advanced social ways of living developed that became the prototypes for all subsequent civilisations to evolve on Earth.

Wasps arrived in the Jurassic Period (200 million to 145 million years ago), although they evolved fastest after the appearance of flowers in the early Cretaceous Period. Many wasps lived alone, but some developed simple social habits, which became more pronounced in bees and ants.

Paper was first manufactured by social wasps tens, if not hundreds of millions of years ago. A queen wasp hibernates over winter, and emerges in early spring to find a suitable nesting site. She starts by constructing a paper nest, using wood fibres which she softens by chewing and mixing them with the saliva in her mouth. The paper she makes is used to construct cells in a comb, each one housing an egg which grows into a female worker wasp. After hatching, the workers finish off the job of building the rest of the nest on the queen's behalf.

Other than starting off the colony, the queen of wasps has no special status in the group, so these colonies represent only the most basic forms of ordered insect society.

Bees, the descendants of wasps, switched from dining on other insects to a diet of pollen and nectar instead. There are about 20,000 different species of bee alive today. Some of these – especially honey bees, bumble bees and stingless bees – formed highly social groups, offering a deep insight into how nature's civilisations work.

Creatures that are "eusocial" divide up jobs between themselves. They pass knowledge and learning on from one generation to another, care for their youngsters and even, in certain circumstances, sacrifice their lives for the benefit of the group. Such characteristics were for a long time thought to be unique to mankind when it first organised itself into tribes and eventually cities and states. But, as any beekeeper will tell you, that is not so.

Queen bees are in overall command of a group of male "drones" and a third set of sterile female workers. Bees communicate with each other through the language of dance. When they return to their hives they dance to inform the others as to the whereabouts of good sources of food. The "round dance" means that food is within 50 metres of the hive. The "waggle dance", which may be vertical or horizontal, provides more detail about both the distance and the direction of the located food source. Then there is the "jerky dance", used by the bees to decide whether to increase or decrease the amount of food gathering they need to do, depending on the hive's overall requirements.

Ants belong to the same family as honey bees: the oldest ant fossil yet discovered is a specimen trapped in amber, estimated at more than 80 million years old. Their civilisations include the Earth's first schools, what look like the beginnings of slavery, and even a bizarre attempt at behaving like an early type of computer. There are many similarities between ants' nests and honey bees' hives, but ants do not dance. Instead, they communicate through chemicals called pheromones that other ants can smell. When an ant finds food it will leave a trail of scent along the ground all the way home, to lead others to its source. It then finds the way back by remembering certain landmarks often using the position of the Sun as its guide. As other ants follow the first trail each one leaves more scent, until the food source is completely exhausted. Once the ants no longer leave a scent the smell evaporates, and the trail is lost for ever.

Ants' smells say other things, too. For example, if an ant gets squashed, its dying gift is a smell that triggers an alarm to all the other ants nearby, sending them into a mad panic as they run around in a rush trying to avoid the same fate.

Ants were also the first creatures we know of that learnt to teach each other. When a young ant makes its first journey out of the nest an older ant will tutor it in the art of finding and fetching food. These tutors slow down to allow the pupil to catch up, and speed up when it draws close (this behaviour has been observed in the species Temnothorax albipennis). They have even been known to link together over gaps to form chains, allowing other ants to scale streams of water like an army with its own portable pontoon bridge.

Termites evolved during the Jurassic Period (200 million-145 million years ago), around the same time as the dinosaurs – of whom more tomorrow. Some fossilised termite nests are thought to date from as far back as 200 million years ago. But they grew more numerous from the Cretaceous Period onwards.

These creatures can create the biggest micro-cities of all. Termites often live in colonies that number several million individuals. A termites' nest is a monarchy, but this time the king rules, with one or more queens by his side. A pregnant queen can lay several thousand eggs a day. She gets so large (sometimes up to 10cm long) that she is often unable to move. If she needs more space, thousands of worker termites heave her up and push her to a newly built chamber. In return, she rewards them with a special form of milk.

Termite civilisations show very high levels of collective intelligence. Compass termites build tall nests that point north–south, to help drive hot-air currents through their elaborate network of tunnels. Temperature control is vital for the good establishment of their growing gardens of fruiting fungi.

The story of civilised insects is largely untold in histories of the Earth, but their worlds go on around us, with important consequences. Sometimes they are under the control of mankind – bees pollinate our orchards and make us honey – and sometimes they cause us annoyance. But, whatever their reputation today, these creatures' powers of organisation, intelligence and self-sacrifice for the good of their kind are the hallmarks of what we have come to call civilised.

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