Difference Between Detritivores and Decomposers

Main Difference – Detritivores vs Decomposers

Detritivores and decomposers are two types of heterotrophic organisms which decompose organic matter. Detritivores are a branch of decomposers. They differ in the nature of their diet, the way of decomposition, and the way they eat. The main difference between detritivores and decomposers is that detritivores are organisms that feed on the dead and decomposing organic matter by oral ingestion while decomposers are organisms that decompose the organic material. Invertebrates such as earthworms and flies are detritivores whereas fungi and microorganisms are considered as primary decomposers.

Key Areas Covered

1. What are Detritivores
      – Definition, Features, Function, Decomposition Cycle
2. What are Decomposers
      – Definition, Features, Function
3. What are the Similarities Between Detritivores and Decomposers
      – Outline of Common Features
4. What is the Difference Between Detritivores and Decomposers
      – Comparison of Key Differences

Key Terms: Decomposers, Detritivores, Humification, Particulate Organic Material (POM), Saprophytes, Scavengers

What are Detritivores

The organisms that feed on dead and decomposing organic matter by oral ingestion are referred to as detritivores. Invertebrate insects such as beetles, flies, butterflies, and mites, slugs, snails, earthworms, millipedes, and woodlice are known as detritivores. Crustaceans like crabs and lobsters, echinoderms like sea stars and sea cucumbers are marine detritivores. Therefore, detritivores are heterotrophs. The organic matter which feeds the detritivores is called detritus. Dead plant and animal material can be considered as the detritus.

Main Difference - Detritivores vs Decomposers

Figure 1: Earthworm

Detritivores can be found in all trophic levels in an ecosystem since they feed on the materials from primary producers, herbivores as well as carnivores. Sometimes, secondary consumers can eat detritivores. The removal of dead material is important in controlling the spreading of diseases. The earthworms in the soil mix up and aerate the soil. This is important in plant growth.

Detritus can be found as particulate organic material (POM) in the environment. These POMs are consumed by detritivores. This consumption fragments the POM into smaller sized pieces. The digestion inside the body of detritivores breaks down the nutrients in the POM such as carbohydrates, lipids, and proteins into smaller substances. The water-soluble materials, which leach out into the soil by the digestion increase the mineral content of the soil. The successive decomposition produces humus. This process is called as humification.

What are Decomposers

The organisms that decompose the organic material are referred to as decomposers. Invertebrates, fungi, and soil bacteria are considered as decomposers. Decomposers can be found in several types as detritivores, scavengers, and saprophytes. The decomposers that feed on feces are called scavengers. Wasps, flies, and cockroaches are scavengers. Coprophagy is the feeding strategy in which the consumption of feces occurs.

Difference Between Detritivores and Decomposers

Figure 2: Fungi

Fungi and other microorganisms are called saprophytes. Saprophytes secrete digestive enzymes on the organic materials and digest them before absorbing the nutrients. Saprophytes also use excreted materials by the detritivores for further decomposition. Fungi are a precise example of primary decomposers. Fungi on decomposing organic material is shown in figure 2.

Similarities Between Detritivores and Decomposers

Both detritivores and decomposers are heterotrophs.
Both detritivores and decomposers play a major role in recycling nutrients in biological cycles such as nitrogen cycle, carbon cycle, and phosphorous cycle.
Both feeding strategies are involved in the consumption of dead matter.

Definition

Detritivores: Organisms that feed on the dead and decomposing organic matter by oral ingestion are referred to as detritivores.

Decomposers: Organisms that decompose the organic material are referred to as decomposers.

Correlation

Detritivores: Detritivores are a type of decomposers.

Decomposers: Detritivores, scavengers, and saprophytes are the three types of decomposers.

Mode of Nutrition

Detritivores: Detritivores break down organic material via oral digestion.

Decomposers: Scavengers eat feces of animals. Saprophytes externally digest organic material by secreting enzymes and absorbing nutrients.

Examples

Detritivores: Invertebrate insects such as beetles, flies, butterflies, mites, slugs, snails, earthworms, millipedes, and woodlice are known as detritivores. Crabs, lobsters, sea stars and sea cucumbers are some marine detritivores.

Decomposers: Bacteria and fungi are saprophytes. Wasps, flies, and cockroaches are scavengers.

Conclusion

Detritivores and decomposers are an important group of organisms that are involved in the digestion of organic material in ecosystems. Both detrivores and decomposers are heterotrophs. Detritivores are a type of decomposers. Detritivores orally ingest the particulate organic material and digest them inside the organism. Most invertebrates are detritivores. The other types of decomposers are scavengers and saprophytes. Scavengers eat feces. Saprophytes secrete digestive enzymes on the organic material and absorb the digested forms of it. Microorganisms such as bacteria and fungi are saprophytes. The main difference between detritivores and decomposers is the mode of decomposition of organic materials.

Reference:

1. “Detritivore – Definition, Function and Examples.” Biology Dictionary. N.p., 28 Apr. 2017. Web. Available here. 03 Aug. 2017.
2. “What is a decomposer?” N.p., n.d. Web. Available here. 03 Aug. 2017.

Image Courtesy:

1. “Mycena interrupta” By JJ Harrison ([email protected]) – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “detritivores” by naturalismus (CC BY-SA 2.0) via Flickr