Detritivores obtain their nutrition by feeding on detritus, which is a heterotrophic organism. Detritus consists of dead plants and animals. Alternatively, detritivores may consume feces for nutrition, a feeding strategy called coprophagy.
Invertebrates such as mites, beetles, butterflies, and flies; mollusks such as slugs and snails; or soil-dwelling earthworms, millipedes, and woodlice are often detritivores.
In marine environments, detritivores include crustaceans such as crabs and lobsters, and echinoderms such as sea stars. Many of these marine detritivores live on or within the benthos, the seabed beneath the surface of the ocean. They are often referred to as “bottom-feeders”. Stationary polychaete worms, barnacles, and some corals obtain energy from floating organic detritus called “marine snow” in aquatic ecosystems.
Although the terms are often used interchangeably, detritivores are technically a branch of decomposers. Unlike detritivores, true decomposers, like fungi, bacteria, and protists, use saprotrophic feeding, where nutrients are absorbed through extracellular digestion rather than oral ingestion.
Scavengers and detritivores share some similarities, however. Despite the fact that both of these feeding strategies involve the consumption of dead plant and animal matter, scavengers typically specialize in carrion and feces.
Function of Detritivores
All dead and decaying material in an ecosystem is broken down by detritivores and decomposers. Therefore, they play an important role in the cycling of nutrients and are essential to many biogeochemical cycles, such as the carbon cycle, nitrogen cycle, and phosphorus cycle.
As detritivores consume material from primary producers, herbivores, and carnivores, they are present in all trophic levels of an ecosystem. In addition to consuming energy from other organisms, detritivores are commonly eaten by secondary consumers, which makes them a crucial component of ecosystem energy cycles.
Recycling is not only an important part of decomposition, but it is also important for stopping disease spread by removing dead materials. In addition, detritivores, such as earthworms, aerate and mix up the soil with their movement, which is beneficial to plant growth.
The Decomposition Cycle
Particulate Organic Material (POM) is formed by tissues deposited after plants and animals die or molt, as well as fecal matter and microorganisms. Among the detritus are colonies of microorganisms that contribute to its nutritional value. A terrestrial environment may contain detritus in the form of humus or leaf litter. Aquatic environments suspend detritus as “marine snow”, which eventually falls to the seabed.
There is energy in all of this material, as well as nutrients in the waste material and the bodies of the deceased. Minerals and compounds are valuable commodities in all energy and nutrient cycles, although they have to be physically broken down and biochemically transformed through decomposition or remineralization.
Detritivores feed on larger particulate material in the early stages of decomposition, fragmenting it into smaller pieces. As a result of fragmentation, more surface area is available for bacteria and other microorganisms to attack, aiding and speeding the process of decomposition.
By digesting the detritus, the detritivores also break down some carbohydrates, proteins, and lipids. As a result, water-soluble nutrients leach into the soil and increase its mineral content. As they extract nutrition for their own life cycles, detritivores contribute biomass to the food chain when they are consumed by consumers.
It is the role of decomposers, such as fungi and other microorganisms, also known as saprophytes, to continuously decompose throughout the process by converting detritivores’ excreted material into simpler substances like inorganic carbon through the use of chemical compounds and digestive enzymes.
Plants use inorganic carbon released by respiration of decomposers to perform photosynthesis, which is an essential part of life.
The decomposition of the modified organic matter results in the formation of humus, a type of soil with a high mineral content.
Examples of Detritivore
Worms are one of the most important soil-dwelling detritivores. They consume a large amount of organic matter and soil and are present throughout all layers of their substrate. Epigeic worms live on the surface, while endogeic worms live in the upper layer of soil.
These two types of worm tend to feed on dead grass, fallen leaves and other bioorganic materials such as fungi, algae and the microorganisms that are also feeding on these substances.
Anecic worms live deep within the soil, primarily consisting off raw soil, although this contains many bacteria, fungi and algae.
Worms take in food through their mouths, and ‘suck’ it into the digestive system using a muscular action. As the material passes through their digestive system into their ‘gizzard’, it is subject to digestive enzymes as well as the grinding action resulting from the presence of grit and sand from the soil.
A ‘cast’ is passed out of the rear end of the worm. The cast is basically a more processed version of the intake soil, with smaller nutrient particles available for decomposition by other organisms. The presence of the microorganisms within the detritus consumed by the worms also speeds up the decomposition process throughout digestion.
Because of their feeding strategy, worms are constantly on the move. This movement helps to mix up and aerate the soil, which also improves water uptake and transportation of nutrients, allowing plants to grow more efficiently.
Springtails are wingless arthropods, which live primarily as detritivores. They are most often found living within leaf litter and other habitats where decaying material is present, such as moss, grass, and dead wood.
Most springtails are vegetarian, feeding on fungal mycelium, vegetation, lichens, pollen and algae although some species have been found to feed on decaying animal matter such as dead earthworms and flies.
They are highly adaptable, with a rapid reproduction rate and a varied habitat and diet range, they colonize in large numbers and are one of the most numerous macroscopic animals; a single square meter of soil can contain around 100,000 springtails! They can withstand a range of temperatures from warm habitats to frozen snow, however they are generally vulnerable to desiccation and so opt for moist environments.
Benefits of Springtails
Springtails have a large effect on the rate of detritus decomposition, and studies have found that the removal of springtails significantly reduces the rate of leaf litter decomposition.
They are important for controlling fungal disease, as they consume spores and mycelium they may remove pathogens.
They can also be used for testing the toxicology of soil. They are highly sensitive to pollutants and so they can be used as bio-indicators of soil quality.
Related Biology Terms
- Decomposer – An organism, which breaks down organic substances, usually into inorganic substances and nutrients.
- Nutrient Cycle – The movement or exchange of organic and inorganic matter throughout biogeochemical cycles into living matter.
- Scavenger – An organism that feeds on the tissue of dead animals (carrion), plant materials, or other waste products.
- Heterotroph – An organism that obtains its nutrition from other organisms.
A detritivore is an organism that obtains its nutrition by consuming dead or decaying organic matter, such as plant material, animal remains, and feces. They play an important role in ecosystem functioning by breaking down organic debris into smaller particles and contributing to nutrient recycling.
Detritivores and decomposers are both involved in the process of decomposition, but they differ in their feeding strategies. Detritivores are organisms that directly feed on the dead organic matter, physically breaking it down into smaller pieces. Decomposers, on the other hand, are microorganisms like bacteria and fungi that break down organic matter chemically through the process of decomposition.
There are numerous examples of detritivores in various ecosystems. Some common examples include earthworms, millipedes, woodlice (rolly pollies), dung beetles, vultures, and certain species of flies and beetles. Many aquatic organisms, such as freshwater shrimp and certain types of snails, also act as detritivores, consuming decaying organic matter in rivers and lakes.
Detritivores play a crucial role in ecosystems by facilitating the decomposition process and nutrient cycling. They break down dead organic matter, making it more accessible to decomposer microorganisms. Through their feeding activities, detritivores release nutrients locked in organic matter back into the environment, enriching the soil or water with essential elements. This recycling of nutrients supports the growth of plants and sustains the overall productivity of ecosystems.
Detritivores occupy an important position in the food chain as consumers of dead organic matter. They are considered primary consumers within the detrital food web, as they convert non-living organic material into a form that can be utilized by other organisms. Detritivores serve as a food source for secondary consumers, such as carnivores or omnivores, that rely on detritivores for energy and nutrients. Their role as recyclers of organic matter links the energy flow between different trophic levels in an ecosystem.