On average, there are 10,000 million insects living in every square kilometre of habitable land on Earth - that's 10,000 in every square metre. Think about that when you next step into your garden or walk along a footpath!

Insects have a much greater impact on the planet than vertebrates. In tropical forests, insects eat 12-15% of the total leaf area, compared to just 2-3% eaten by vertebrates. Insects eat 15-20% of all crops grown for human food.

A leaf-cutter ant colony contains millions of individuals: they excavate a room-sized underground chamber in which they cultivate fungus gardens.

The largest known beetle is the Titan beetle of the Amazonian rainforest: the adults are up to 17cm long.

Fossils from the Carboniferous period show that some early dragonflies were much bigger than today's: they had a wingspan of up to 76cm - wider than a pigeon's.

The smallest insects are fairyflies - minute parasitic wasps that 'fly' underwater with wings that are simple hair-fringed struts.

Termites invented air conditioning millions of years ago: their massive mounds are a complex ventilation system for the underground nest of the colony.

Individual termites are small but there are so many of them living in the soil of the African savannah that their biomass per square kilometre is twice that of the herds of grazing game animals above them.

Dragonflies are among the fastest flyers over normal distances: they can reach speeds of up to 36mph.

Insects were farmers long before humans: termites cultivate fungus gardens under their mounds; leaf-cutter ants make underground compost heaps; and many ant species tend and protect 'herds' of aphids to gather their honeydew.

The invasive harlequin ladybird only arrived in southeast England in 2004 but it has already spread north and west across much of Britain. Like many ladybirds, it helps to control aphid pests, but it also competes with some of our native ladybird species and may pose a threat to their survival.

The beautiful large blue butterfly, which became extinct in the UK by 1979, has now been reintroduced and is thriving in several locations in southern England after researchers discovered how its life-cycle is intimately linked to that of a particular species of red ant.

Based on information provided by BBC's Life in the Undergrowth.