Mites

Mites are almost as cute as springtails. They are only a few millimetres long and are arachnids with four pairs of legs. These legs can be long in the fast-moving predatory mites or tucked up under their heads in some slow-moving decomposer mites. They are hard-bodied and more tolerant of dry conditions than springtails. If you are monitoring numbers of springtails and mites and the weather turns dry, it is the springtails that succumb to drought first. If drought persists, the mites eventually die too.

Mites live mainly in the top 10 cm of soil, in leaf litter and dung and on vegetation. Like springtails, mites live in the air-filled soil crevices and pores as they are too tiny to push their way between soil particles to make their own burrows. Mostly they are beneficial animals, helping decompose organic matter and return nutrients to the soil. Some are plant pests such as the red-legged earth mite which attacks clovers.

Mites, like springtails, occur wherever there is soil - they are ubiquitous. They occur in similar habitats as springtails, even in the intertidal zone of beaches! They always live together and are lumped into the group of small soil animals called "microarthropods".

Mites feed on much the same things as springtails - decaying organic matter and the microbes (e.g. fungi) that live on organic detritus, dung, wood, compost and carrion, as well as green plants and other small soil animals (nematodes, springtails, other mites and their eggs). Some can bore into pine needles and twigs.

Ticks

Ticks are close relatives of the mites. They spend part of their lives in the soil but are parasitic on vertebrate animals. They are out for a free meal at our expense. They burrow into skin, suck our blood and then fall back into the soil to breed. During feeding, ticks inject saliva which contain toxins which can cause paralysis, eventually killing small pet animals. They also transmit disease such as Lyme disease overseas.

Hitching a ride: if you pick up some beetles (dung beetles are a favourite) and inspect them carefully, you might see some tiny brown hitch-hikers clinging onto the beetle. These free-loaders are predatory soil mites that are getting a free ride from dung pat to dung pat with the dung beetles. This is very clever of the mites as not only do they get dispersed with the minimum of effort on their part, but they are transported to a fresh, rich source of nematodes and fly eggs on which they feed. This behaviour is called "phoresy".