Eucharitid Wasps

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Eucharitidae is a family of parasitic wasps known as Eucharitid wasps. Eucharitid wasps are members of the superfamily Chalcidoidea and consist of three subfamilies: Oraseminae, Eucharitinae, and Gollumiellinae. There are 55 genera and 417 species of Eucharitidae; most of which are members of the Oraseminae and Eucharitinae subfamilies. Most Eucharitids live in tropical regions of the world.

Eucharitids are specialized parasitoids of ants, meaning each species is usually only parasitic of one genus of ant. Furthermore, they are one of the few parasitoids that have been able to utilize ants as hosts, despite ants’ effective defense system against most parasitoids. Eucharitidae parasitism occurs year round, with a majority of it occurring during hot and humid months. However, the amount of parasitism that occurs depends primarily on the size of the ant colony and the number of host pupae in them, and not on the season.

Female Eucharitids oviposit rows of eggs into plant tissue, such as leaves and stems, away from ant colonies. The eggs are a translucent white and are about 0.019 mm long and 0.08 mm wide. They are elliptical and flat on one side. As the eggs mature they turn a brown color and ten days after oviposition they hatch. The larvae are solely responsible for their entry into the ant colony and the parasitism of their host. They are 0.13 mm long and are able to travel several inches on the leaf but do not leave the egg cluster. After six to seven days they attach themselves to foraging ants heading back to their brood; however, sometimes they will attach themselves to other insects, using them as an intermediate host. Once in the brood, the larvae will attach to their host larva. Some Eucharitdae are external parasites while others are internal parasites; however, all Eucharitid species finish their development as ectoparasites.

Limited feeding on the host occurs until the host pupates; after which, most of it is consumed by the wasp. Usually, there is only one parasite per host, but in some cases superparasitism occurs, and two to four wasps will attach to, and emerge from one host. Once the wasps emerge, the ant colony grooms and feeds them as if they were part of the ants’ brood. In some instances worker ants have been observed assisting the wasps emerge from its host. The wasps gain acceptance in these ways, and the ants show no signs of aggression because the wasps acquire their host's odor upon entry into the colony. By mimicking the odor of their host, Eucharitid wasps are able to keep themselves safe until the scent wears off, at which point they begin to leave the ant colony and begin mating.

Adult wasps emerge from the ant nest in the morning; the males emerge before the females. In most cases, the males swarm one to two feet above the nest, and as soon as the females emerge mating occurs. However, the males of certain species, such as Kapala Terminalis, calmly wait on folliage surrounding the nest until the females emerge. Many times the males will begin mating with the females before they have a chance to take flight and in some instances mating will occur while the wasps are still inside the ants nest. After mating, the females lay their all their eggs in one day. The egg capacity of each female is anywhere from 1000 to 10000.