Parasitoids

Parasitoids of ants may occupy a variety of ecological niches within their host ant colony. Most are internal parasites of ant brood and ant adults. Many are hymenopterans and dipterans as well as Strepsipterans. There is another subset of parasitoids that attack myrmecophiles and other organisms living with the ants (eg. Horismenus, Microdonophagus). Ant parasitoids are a possible agent for biocontrol of pest ants. Most parasitoids are obscure and poorly known. Some species attack ants as well as other insect hosts.

Eucharitidae
Eucharitidae parasitize the immature stages of Formicidae and are among the most diverse hymenopteran parasitoids of eusocial insects. Females are oviparous and proovigenic and lay their eggs inside or on plant tissues, either individually or in masses. They oviposit away from the host, with the active first instar larva (planidium) responsible for getting into the ant nest through various associations with foraging adult ants. Once in contact with the larval ant host, the planidium either remains as an external parasite or burrows into the host. Upon pupation of the host, the larva migrates to the ventral region of the thorax, just posterior to the legs of the newly formed pupa, then resumes development through two additional instars. The adults emerge and leave the nest on their own or may be carried by the ants and deposited in the accumulation of colony waste.

Worldwide, approximately 700 Eucharitidae species attack five subfamilies across the ant phylogeny.