Parasitoid

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Image:Collinia sp.jpg A parasitoid spends a significant portion of its life history attached to or within a single host organism which it ultimately kills and consumes. Thus they are similar to parasites except in the fate of the host. In a truly parasitic relationship, the parasite and host live side by side with little damage to the host. The parasite takes enough nutrients to thrive without preventing the host from reproducing. In a parasitoid relationship, the host is killed before it can produce offspring.

This type of relationship seems to occur only in organisms that have fast reproduction rates (such as insects or mites). Parasitoids are also often closely coevolved with their hosts.

An endoparasitoid lives inside of the prey, while an ectoparasitoid lives outside.

There are three groups of insect that are particularly renowned for this type of lifestyle. The largest and best known group comprises the division Apocrita: Parasitica of the order Hymenoptera (including the chalcid wasps (family Chalcidae) and the ichneumon wasps (family Ichneumonidae). The other two are the tachinid flies (order Diptera, family Tachinidae) and the stylopid flies (order Strepsiptera, family Stylopidae).