Terrestrial Invertebrates

Great green bush-cricket (c) Steven Falk

Types of Terrestrial Invertebrates in Britain

Annelida (segmented worms)


Oligochaeta (earthworms and oligochaete worms)

Charles Darwin said of Earthworms ‘It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.’

Earthworms are amazing! There are 25 species of earthworms native to the UK varying in size from 9-35 cm long. Their combined actions are astounding – it has been estimated that earthworms produce £16 billion of topsoil each year! Earthworms aerate the soil and are fantastic recyclers. Spring is a great time to celebrate worms – they are becoming more active and as we dig over our gardens and plant seeds we do see more of them and are reminded of what they do for us!

Lumbricus terrestris Mating (c) John-Mason

Hirudinea (leeches)




Isopoda (woodlice)

There are about 35 different types of woodlouse in the UK.

The pill woodlouse can roll up into a ball when it is frightened.

Woodlice like damp, dark places and can be found hiding in walls, under stones and in compost heaps. Some species such as the common sea slater are only found on the coast.

Our largest woodlouse, the sea slater can grow up to 3cm long.

A woodlouse has 14 legs and an outer shell called an exoskeleton. When a woodlouse grows too big for its exoskeleton it has to moult to allow a new shell to take its place. Moulting takes place in two stages, first the back half is shed and a day or so later the front half falls off.

Woodlice eat rotting plants, fungi and their own poo!

They also don’t pee! Instead they get rid of their waste by producing a strong-smelling chemical called ammonia which passes out through their shells as a gas.

After mating, female woodlice carry their fertilised eggs in a small brood pouch under their bodies. The young hatch inside the pouch and stay there until they are big enough to survive on their own.

A common woodlouse can live for 3-4 years. Its main predators are centipedes, toads, shrews and spiders.

Pill Woodlouse – Armadillium vulgare (c) Ed Phillips
Amphipoda (sand-hoppers)



Scorpiones (scorpions)
Aranea (spiders)

Opiliones (harvestmen)
Pseudoscorpiones (pseudoscorpions)
Parasitiformes (ticks)
Acariformes (mites)


Chilopoda (centipedes)

Diplopoda (millipedes)
Pauropoda (pauropods)
Symphyla (symphylans)


Collembola (springtails)
Diplura (diplurans)
Protura (proturans)
Thysanura (silver-fish)
Microcoryphia (bristletails)
Ephemeroptera (mayflies)
© Peter Orr
The winning image in the ‘Flies, Bees, Wasps and Dragonflies’ category shows three mayfly on crested dogstail, and was shot on the River Kennet near Kintbury, in the UK.
Odonata (dragonflies)

Plecoptera (stoneflies)

Blattaria (cockroaches)
Dermaptera (earwigs)
Orthoptera (grasshoppers and crickets)

Phasmida (stick insects)

Psocoptera (booklice)
Mallophaga (biting lice)
Anoplura (sucking lice)
Thysanoptera (thrips)
Heteroptera (true bugs)

Homoptera (aphids, cicadas, etc.)

Coleoptera (beetles)
bug 3

Strepsiptera (stylopids)

Bees, wasps, ants and sawflies – A huge and varied Order of insects, with over 7000 species in Britain.  Included are the following:-

Symphyta (sawflies)

They are primitive, the larvae looking very like butterfly caterpillars except with legs on nearly all segments.  They eat leaves just like caterpillars, and a few make galls.  The adults of some species visit flowers for nectar, or more commonly eat other insects.  Britain has nearly 500 species.

It’s amazing: Remember, they invented the saw first, to cut a slot into a plant to lay their eggs.

Parasitica (parasitic wasps)

These wasps are parasites of other invertebrates (technically parasitoides since they often kill the host) or their larvae are in living plant tissue where they may form galls.  This is an immense and complex group of wasps with many different life histories.  They are abundant and play a vital role in the checks and balances in populations of other invertebrates.  Britain has approaching 6000 species.

It’s amazing: Some are so tiny they can ‘fly’ underwater to parasitise minute water beetle eggs.

Aculeata (bumblebees, bees, wasps and ants)

BEES.  These feed on nectar and gather pollen to feed their larvae. though some have become cuckoos of pollen gathering bees.  The largely domesticated hive bee and all bumblebees form colonies with a queen in charge, supported by workers.  However, the great majority of species of bee are solitary, without workers.  Bees are of considerable importance as pollinators of crops and wild flowers.  Britain has about 260 species.

It’s amazing: Plant and bee evolution have been interdependent.

WASPS.  Most feed their larvae on other insects.  The hornet and ‘jam pot’ wasps are social species, with queen and workers developing colonial nests.  The great majority of species are solitary.  Some are significant pollinators, but most play an unobtrusive part in various webs of life.  Some are cuckoos on nest provisions of other wasps, and some bizarre relatives are internal parasites of leaf-hoppers.  Britain has about 350 species.

It’s amazing: They may look dangerous but most are harmless.

ANTS.  Most are colonial, and have nests with a few to thousands of workers depending on age of nest and species concerned.  Some ants specialise in living in small numbers in the large nests of other species of ant.  Usually nests are out of sight underground, but some species extend their nest into a mound above ground.  Some species of ant collect seeds to eat, but most are predatory on other tiny creatures and are found of honey dew secreted by aphids; some even manage and protect aphid colonies, milking them like a herd of cows.  Britain has about 50 native species.

It’s amazing: Some species farm plant bugs like cows.

Sea aster mining bee (c) Steven Falk


Raphidioptera (snakeflies)
Neuroptera (ant-lions, lacewings, etc.)
Chrysoperla carnea Common green lacewing
Megaloptera (alderflies)
Mecoptera (scorpionflies)
Diptera (true flies)

Flesh Fly – Sarcophaga Species (c) Ed Phillips
Nematocera (craneflies, midges, etc.)
Brachycera (hoverflies, etc.)
Siphonaptera (fleas)
Trichoptera (caddisflies)
Lepidoptera (moths and butterflies)
Peacock butterfly (c) Amy Lewis

Pentastoma (tongue-worms)



Brown lipped snail (c) Mike Dodd

Gastropoda (snails and slugs)


Nematoda (round-worms)


Nematomorpha (horsehair worms)


Platyhelminthes (flatworms)

Turbellaria (free-living flatworms)

Monogenea (flukes)

Trematoda (flukes)

Cestoda (tapeworms)




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