What Are Detritivores?
Detritivores are organisms that survive by consuming decaying organic material, known as detritus. They are typically animals, although some fungi are sometimes classed as detritivores. These organisms play a vital role in a variety of different ecosystems, helping to break down dead matter and release the nutrients stored within it for use my other organims.
In ecology, the terms "detritivore" and "decomposer" are often used interchangeably. These two types of organism do play similar roles in the ecosystem, but they are not exactly identical. Decomposers, rather than ingesting dead organic matter as detritivores do, absorb nutrients on a molecular scale. Similarly, although scavengers play a similar role and some ecologists may include the two types of organism in a discussion for the sake of simplicity, scavengers and detritivores operate on a different scale, with scavengers generally being larger organisms which consume larger amounts of organic matter. A detritivore might feed on the droppings of scavengers or on the parts of carcasses left behind.
The role of this type of organism in the nutrient cycle is to consume dead organic material such as carcasses, fallen leaves, dead plants, animal droppings, and shed skins. Having consumed the material, the organism then excretes or egests waste. This waste contains nutrients which are thus returned to the soil, facilitating new plant growth, or made easier for other organisms to consume. By breaking down dead matter into smaller pieces, detritivores speed up the process of decomposition. The greater surface area of processed waste compared to a dead organism makes it easier for decomposers such as bacteria and fungi to complete the nutrient cycle, breaking up these last remains at a molecular level.
Detritivores make up a significant part of most ecosystems. In many biomes, detritivores make up half of the biomass, excluding plants and bacteria. Common species of detritivore include earthworms, slugs and many species of insect such as flies. Marine detritivores include crabs, sea stars and many species of fish and worm.
One of the most ubiquitous terrestrial species of detritivore is Armadillidium vulgare, also known as the woodlouse or pillbug. This small animal is actually a crustacean of the Isopod order, not an insect. Pillbugs typically consume dead vegetable matter such as fallen leaves or refuse. When pillbugs overpopulate, however, they will sometimes feed on living plants, including cultivated plants, which leads humans to regard them as pests. Although primarily detritivores, pillbugs, like many organisms, can change their behavior as a response to changing circumstances.
@strawCake - I remember being really interested in earthworms and caterpillars when I was younger. For some reason I always thought they were kind of similar, but biologically it sounds like they aren't.
I've actually never given too much thought to the scavengers and decomposers of the natural world. Most people seem to find scavengers gross, but the world wouldn't continue on without them!
When I was a kid I used to go out after a rainstorm and look at all the earthworms. I thought they were just so fascinating. However, I never got around to finding out what their actual function in the world was.
I think it's so interesting that earthworms are detrivores. I guess the name earthworm really make sense! They basically digest dead matter and return the nutrients to the earth.
For those that enjoy looking after marine aquariums adding detritivores like cerith snails to your tank can really improve the quality of life for your fish and the plants in it.
A lot of people find that they have trouble dealing with the fecal matter in aquariums and in essence, adding something like cerith snails to your tank can be an easy way to help clean things up.
As the process of having a detritivore in your tank is painless and things go as nature intended, why not do it?
While thinks like cerith snails aren't beautiful, they definitely serve an important function that shouldn't be overlooked.
Detritivores are fascinating and it always amazes me at how our world manages to look out for itself. If your kids like science then showing them what detritivores do for the environment can really be a great project.
All you need is a small aquarium and some pillbugs or earthworms for your experiment. Just fill the aquarium half full with soil and add in a few leaves and your bugs of choice.
The bugs will take care of the leaves when they start to decompose. It's a very simple thing for kids to watch but if they are anything like my kids, having "pets" to study can be quite interesting.
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