Bug life has survived and thrived for hundreds of millions of years. Bugs have
witnessed the rise and fall of the dinosaurs, and the evolution of almost every
other group of land based animals.
Secrets to Survival
The success of bugs has occurred because of several amazing adaptations. Bugs
are small, which means they need less space and food to survive. They fit into
the ‘cracks and crevices’ of nature. The tiniest beetles are smaller than the
head of a pin.
Bug survival is assisted by their ability to exploit almost all habitats and
withstand extreme conditions. They are able to survive temperatures from
-30°C to +50°C. Brine Fly larvae can be found in pure salt.
Petroleum Fly larvae can live in crude oil.
Insects were the first animals to develop wings, and for 90 million years they
were the only animals to fly. Wings greatly improve an insect’s ability to
escape from predators, locate new food sources, migrate to new habitats and
Most insect species make dramatic body changes between their larval and adult
stages, in a process known as metamorphosis. This allows adults and larvae to
exploit different foods, seasons, habitats and lifestyles.
The rapid rate of reproduction of many bugs is also a great advantage. A queen
bee can produce 600,000 eggs in her lifetime. A female House Fly and her
offspring can produce 56 trillion descendants in a single summer.
There are very few insect fossils. Insects are small and very fragile, and to
fossilise they need to fall into fresh water deposits, mud or silt and be
covered quickly. The insect decomposes and its impression is left in the
mudstone, shale or limestone that forms around it.
The fossilised remains of insects have been found in rocks dating back 400
million years, from the Early Devonian Period. The oldest fossil spiders date
back about 325 million years ago. The first dinosaurs didn’t appear on the
earth until about 230 million years ago.
The best evidence we have of ancient insects comes from fossilised tree sap,
called amber. Tree sap hardens over time into a plastic like substance,
perfectly preserving the bodies of any insects that may have become trapped in