Eucharitidae
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| 2 subfamilies 53 genera c. 470 species |
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Eucharitinae |
The Eucharitidae are a specialized group of ant parasitoids within the Chalcidoidea. There are 53 genera and >470 species worldwide, mostly in the tropics; very few genera are shared between the Old and New World. They are often peculiarly "hunch-backed", with a bulbous mesosoma and a small, petiolate metasoma. They are generally very strongly sculptured, often with strong spikes or prongs projecting backwards from the thorax, and are generally dark, sometimes metallic. The prothorax is not visible from above, and the labrum is multidigitate. This latter feature is shared with the Perilampidae, the family from which the Eucharitids apparently are derived.
Eggs of eucharitids are deposited into plant tissue. Oraseminae and Psilocharitini deposit their eggs into punctures made by the ovipositor, Eucharitini all deposit their eggs into preformed cavities (plant buds or inflorescences), onto the undersurface of leaves, or into the outer skin of fruits. As in Perilampids, the first-instar larvae are called "planidia" and are minute, less than 0.13 mm, strongly sclerotized, active, and are responsible for gaining access to the ant host. Access to the host ant colony is by various means, most often through phoresy on intermediate hosts, or directly via ant workers.
Larval development takes place in the ant nest. Eucharitine planidia attach externally to the host larva, whereas Oraseminae all burrow into the host thorax just behind the head and do limited feeding (slight expansion of tergites). Further development does not take place until the host pupates. In all cases, the first instar larvae migrate to the ventral region of the host pupa where they feed until most or all of the host is consumed. Only one host is consumed and only very rarely do more than one eucharitid develop on a host. Adults emerge within the nest and may remain for a period of time (unknown how long) within the nest. Adults, and immature stages where exposed, are generally well treated within the nest by the ants, which will feed them, groom them or carry them away to protect them if the colony is under attack, suggesting chemical mimicry of the host ants. Adults must leave the nest to mate and lay eggs.
