Fungi
Plant material, mainly from moss, bracken, pine needles and bark is consumed by worms and mites, particularly sciarid larvae (young fungus gnats) and phthiracarid mites (primitive oribatids). Fungal material (+ or - plant material) is ingested by many small soil animals, like camisiid and oppiid mites, lots of Collembola, and sciarid and chironomid larvae
Some research involves examining the guts of various soil animals, (can you imagine that job?) so we know more about their eating habits. More on soil animals diets. They found:
"Plant material, mainly from moss, bracken, pine needles and bark, was extensively consumed by enchytraeid and lumbricid worms, sciarid (Fungas gnats) larvae and phthiracarid (sort of Oribatid) mites. Fungal material was ingested by all groups, either in combination with plant material or alone (camisiid and oppiid mites, some species of Collembola, sciarid and chironomid larvae) (adult flies for fishing). Isotomid springtails
From Fundamental of Soil Ecology Coleman, Crossley & Hendrix
Soil invertebrates influence microbial populations, and hence indirectly affect total metabolism, by :
* Regulating fungal growth (Warnock et al., 1982; Ulber, 1983; Gochenaur, 1987),
* Disseminating fungal and bacterial propagules into new substrates (Visser et al., 1981) or
* Reactivating senescent microbial colonies (Hanlon, 1981).
Rhizosphere
The 'Rhizosphere dynamics' includes the roots and their relationship with bacteria (like nitrogen fixing bacteria - see 'deep down') and fungi - particularly Mycorrhiza fungi. This term was first created over 130 years ago - Glossary. These fungi are attached to the root and take sugars from roots for their own energy and return soluble nutrients in the soil; these will have come as part of the breakdown products of decomposers like oribatids (see below). This is a crucial part of the overall life cycle of the world/earth. It means trees can access mineral nutrients to be fed properly. The fungi also increase the surface area of roots to enable more transfer of chemicals in and out.
The springtails play a positive role in the establishment of plant-fungal symbioses and thus are beneficial to agriculture.[look at source] You could call them 'the bees' of the soil as an indicator of how important they are - and how, like bees, carry out a vital functions, quite accidentally.
Fungi do not go that deep into soil - about 18-20 inches.
Nematodes
The most prolific animals underground are the nemnatodes. They have been around several hundred million years, and now have seven sorts depending on their feeding tructures. they were originally pplant eaters, but now many are free-living.
Click this image and see how they can be trrapped by fungal mycelia. Whoever can replicate the fungal glue could make a fortune.
Worms
The endogeic earthworms include Lumbricus rubella. They have deeper horizontal burrows. They are like massive earth moving equipment and are the ones we may see bringing a leaf down their burrow
Worms working a field, then themselves
Insect larvae:
Several insects lay their eggs in soils for the larval stage to grow in soil. Some are well-known pests, like 'leatherjackets' and wireworms
Starlings eating bibionid larvae infestation
Wireworms
These 'click' beetles produce wireworms often a pest on lawns
Leather jackets
Can be a plague under lawns. They develop into the familiar daddy long legs.
Vine Weevils:
Video of vine weevil larvae (white brown head), with pupae nearby kicking legs and hatching into adult insect. They love soil in pots. They are becoming a plague in garden centres according to RHS.
Bibionid larva
Llike many soil living insect larvae, with white coloured segmented body, and dark head. They turn into these
Let's go a bit deeper DOWN DEEPER