A form of parasitism wherein an organism (called parasitoid) lives on or inside the host at one phase in its life cycle, and usually ends up in the death of the host
Parasitism is one of the many forms of symbiosis. In parasitism, one organism (called parasite) benefits at the expense of another organism usually of different species (called host). The parasite benefits at the expense of the host organism. A special form of parasitism is parasitoidism. Parasitodism is a form of parasitism involving a parasitoid organism. Certain insect species are parasitoids. An example is a wasp ovipositing into the body of an alfalfa aphid. Taking this as an example, the parasitoid wasp requires that its parasitic developmental (larval) stage is spent within the alfalfa aphid host. The gravid female wasp deposits the eggs into the body of the host. The larvae are released from the eggs and begin to feed on the tissues of the host. The host lives up until the larval stage of the parasitoids; the host eventually dies when the parasitoids complete the larval phase, and are then released from the host to live freely as an adult parasitoid.