Some workers differentiate into two more categories of living beings amongst the biotic components of an ecosystem. These are detritivores and parasites. Parasites belong to diverse groups, $e \cdot g .$, bacteria, fungi, protozoans, worms, etc. Every type of living being can be attacked by parasites. Detrivores or scavengers are animals which feed on dead bodies of other organisms, $e . g .$, termites, carrion beetles. They are helpful in quick disposal of the dead bodies