Words by: Clare Hunt Clare is a writer and smallholder novice enjoying the good(ish) life in Devon
WHETHER YOU FIND them horrifying or fascinating, it’s hard to get away from insects. Some you can see, others you can’t, but either way, they’re all around us. So let’s have a rootle in the leaf litter and see what creepy-crawly friends we can find…
First things first, let’s talk about terminology. Botanists and zoologists classify life on Earth using a mind-bogglingly complex taxonomic system. This was devised in the 1750s by Swedish scientist Carolus Linnaeus and arranges plants and animals into categories, starting from the broadest and funnelling down to the most specific.
At the highest level of zoology, we have the animal kingdom, which includes all living creatures. Within the kingdom, there are several categories known as ‘phyla’, one of which is the arthropods. There are around a million known arthropod species and probably many more as yet undiscovered.
These species fall into four subphyla: chelicerata (arachnids), crustacea (crustaceans), hexapoda (insects) and myriapoda (millipedes and centipedes). While many of the creatures we know commonly as insects aren’t technically hexapoda, this category contains the majority of arthropod species. And ‘insect’ is a handy catch-all word, so let’s use it loosely here.
An estimated 75% to 90% of all animals on earth are arthropods. These invertebrate creatures all have features in common. Durable exoskeleton made of a polymer called ‘chitin’? Tick. Bilaterally symmetrical segmented body? Tick. Pairs of jointed limbs? Tick. Likely to give you the heebiejeebies? Tick, tick, tick. Although all species in the phyla share these characteristics, nature went to town when designing the arthropods and diversity is the name of the game. So, what can be found within each subphylum?
Chelicerata: mainly terrestrial, the arachnids have two body parts and twelve appendages – eight for walking and four used as mouthparts. Species include scorpions, spiders, mites and ticks.
Crustacea: mainly water-dwellers, the crustaceans have distinctive antenna and ‘open’ circulatory systems without veins. Species include lobsters, crabs, woodlice and water lice.
Hexapoda: the true insects live on the land or in aquatic habitats. They have three body parts (head, thorax, abdomen), six legs and often – but not always – wings. Species include bees, butterflies and beetles, as well as dragonflies, grasshoppers and earwigs.
Myriapoda: land-living myriapods (from the Ancient Greek for ‘ten thousand feet’) ha
