Ants
Beetles
Centipedes
Fruit Beetle
Millipedes
Mites
Redworms
Sowbugs
Springtails

Bacteria

Bacteria don't have to be added to the compost pile. They are present virtually everywhere and enter the pile on every piece of organic matter.

Many types of bacteria are at work in the compost pile. Each type thrives on special conditions and different types of organic waste. Psychrophilic bacteria (a group of bacteria species that work in the lowest temperature range) do their best work at about 13°C (55°F), but they are able to carry on right down to -20°C (0°F).

During the beginning of the composting process (0-40°C, 32-104°F), mesophilic bacteria predominate. In passive compost piles, these midrange composters do most of the work but in active "hot" compost piles, the real hot shots, thermophilic bacteria, will kick in.

The fast working thermophilic bacteria take over as the compost heats up above 40°C (104°F). The diversity of bacterial species is fairly high at temperatures from 50-55°C (122°F-131°F) but decreases dramatically at 65°C (150°F) or above.

Once the compost cools down, mesophilic bacteria again predominate. The numbers and types of mesophilic microbes that recolonize compost as it matures depend on what spores and organisms are present in the compost as well as in the immediate environment. In general, the longer the curing or maturation phase, the more diverse the microbial community it supports.