Earthworms are scavengers.
Detritivores are organisms that survive by consuming decaying organic material, known as detritus. They are usually animals, although some fungi are sometimes classified as scavengers. These organisms play a vital role in a variety of different ecosystems, helping to break down dead matter and release the nutrients stored in it for use by other organisms.
In ecology, the terms “detritivore” and “decomposer” are often used interchangeably. These two types of organisms play similar roles in the ecosystem, but they are not exactly identical. Decomposers, instead of ingesting dead organic matter like detritivores, absorb nutrients on a molecular scale. Similarly, while scavengers play a similar role and some ecologists may include both types of organisms in a discussion for the sake of simplicity, scavengers and scavengers operate on a different scale, with scavengers generally being larger organisms that consume large amounts of organic matter. A scavenger may feed on scavenger droppings or carcass parts left behind.
The role of this type of organism in nutrient cycling is to consume dead organic matter such as carcasses, fallen leaves, dead plants, animal feces, and discarded fur. Having consumed the material, the organism excretes or excretes waste. These residues contain nutrients that are returned to the soil, facilitating the growth of new plants or being easier for other organisms to consume. By breaking down dead matter into smaller pieces, scavengers speed up the decomposition process. The larger surface area of processed waste compared to a dead organism makes it easier for decomposers like bacteria and fungi to complete the nutrient cycle, breaking down these last remnants at the molecular level.
Detritivores constitute an important part of most ecosystems. In many biomes, detritivores make up half of the biomass, excluding plants and bacteria. Common species of scavengers include earthworms, slugs, and many species of insects such as flies. Marine detritivores include crabs, starfish, and many species of fish and worms.
One of the most ubiquitous terrestrial species of detritivores is Armadillidium vulgare, also known as the wood louse or stink bug. This little animal is actually a crustacean of the order Isopods, not an insect. Bed bugs typically consume dead plant matter, such as fallen leaves or debris. However, when bed bugs become overcrowded, they sometimes feed on living plants, including cultivated plants, leading humans to consider them pests. Although they are primarily scavengers, bed bugs, like many organisms, can change their behavior in response to changing circumstances.