What's Bugging me? - Beneficial Compost Guests

Most of the living things that gardeners see when they peer into their compost piles need to be there for compost to happen. Earthworms, white worms, sow bugs, pill bugs, millipedes, snails, slugs, and mites all help break down the organic matter in the compost pile. They work with a web of microscopic organisms and fungi to turn garden and kitchen scraps into the black gold composters are after.

Think of these bugs as beneficial, decomposer macroorganisms, we can see them, they grind, chew, bite, and tear up the materials we add to the compost pile. Let's look at a few beneficial compost guests:

Soldier flies, Hermetia illucens - Soldier flies are native to the Western Hemisphere. The fly itself lives about a week. It does not sting or eat any food during this time, but it does drink water. Black soldier flies can be seen in bright, sunlit areas, resting on nearby structures or vegetation and frequenting flowers of the daisy and carrot families. They have a wasp-like appearance. They are one of the most beneficial flies in existence and are considered non-pests. The adult black soldier fly does not have mouthparts and does not feed upon waste. They do not bite, and as only the larva feed, are not associated with transmitting any diseases. Also, this species makes the breeding areas of houseflies less desirable. The larval stage is usually quite long and is the main life of this insect. It goes through six stages as a larva. They are voracious eaters: a thousand larvae eat over two pounds of food a day. They will eat almost any kitchen garbage except eggshells (which worms love), weeds, paper, and cardboard. The larval stage is the beneficial stage.

Earthworms are one of the major decomposers of organic matter. There are two major types of earthworms – the deep-burrowers ("nightcrawlers,” Lumbricus terrestris) and the shallow-dwelling worms (commonly known as redworms, Eisenia foetida) that live primarily in the top twelve inches of soil/compost. FYI, Eisenia foetida is the worm of choice in vermicomposting.

Earthworm contributions to your compost pile include stimulating microbial activity, they burrow and move particles around which increases air flow in the pile and assists in water retention and earthworms produce (excrete) castings that contribute to the nutrients available in your compost and eventually your soil.

Sowbugs/Pillbugs, Armadillidium vulgare, feed primarily on decaying plant material and are important decomposers of organic matter.

There are many species of Millipede. The common millepede, Diploiulus luscus, is one of three species commonly found in our area. Millipedes normally live in and feed on rotting leaves, rotting wood, and other kinds of moist, decaying plant matter. Millipedes are beneficial as "recyclers" as they break down decaying organic matter. Millipedes are not harmful; they cannot bite or sting and they do not attack people, property, possessions or pets. 

Millipedes have an elongated, worm-like body with two pairs of short legs on the underside of each body segment. The common millipede is approximately 1 inch long with a hard, rounded, cylindrical body that is brown to blackish in color. They have short, inconspicuous legs and they usually coil into a spiral when touched or disturbed and when dead.

Earwigs, Forficula Auricularia, Earwigs feed most actively at night and seek out dark, cool, moist places to hide during the day. They recycle organic debris in the compost pile. For more information about earwigs check out our Summer 2022 Coastal Gardner

So, the next time you add organic material and turn your compost pile say thanks to these decomposers.

 

Resources:

Texas Agrilife Extension - Soldier Flies Article 

University of Georgia Cooperative Extension - Compost Pile Health can be Judged by the Company it Keeps Article  

UC Orange County Master Gardeners - Why Are These Bugs in My Compost Pile? Video S

UC San Joaquin Master Gardeners - Vermicomposting Composting with Worms Article

UC Marin Master Gardeners - Garden Good Guys - Earthworms Article 

UC IPM Pest Notes 7472 Centipedes and Millipedes 

Iowa State University Extension & Outreach - Millipedes Article 

 

Images Credits - used with permission from UC ANR

Adult Millepede - UC IPM by Jack Kelly Clark

Soldier Fly Adult - UC IPM by Kathy Keatley Garvey

Nightcrawler - UC ANR Research & Education Program - Earthworm Information photo by Jack Kelly Clark