page_title: Eucharitidae
section_title: Oraseminae
hierarchical_section_title: Eucharitidae / Subfamilies / Oraseminae
caption_attribution_description: English: Orasema simplex, specimen from Argentina: Corrientes Pr.: EBCo, 70m 27°33'10"N 58°40'46"W 24 Feb 2005 L. Varrone ex. S. invicta
context_page_description: The Eucharitidae are a family of parasitic wasps. Eucharitid wasps are members of the superfamily Chalcidoidea and consist of three subfamilies: Oraseminae, Eucharitinae, and Gollumiellinae. Most of the 55 genera and 417 species of Eucharitidae are members of the subfamilies Oraseminae and Eucharitinae, and are found 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 use ants as hosts, despite ants’ effective defense systems against most parasitoids. Eucharitid 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.
context_section_description: Oraseminae are parasitic on the ant genus Pheidole (Myrmicinae), as well as the fire ant in southern South America and the little red fire ant in the Caribbean.  They are distributed worldwide in tropical regions, such as Costa Rica, Ecuador, Brazil, and Argentina. They are also native to Texas, Florida, Massachusetts, Delaware, and Colorado.
  The Oraseminae female punctures the plant tissue on which she will oviposit, and places an egg inside of each incision.  The eggs are deposited on the edges of the underside of leaves, and are sometimes found in the buds and stems of the plant.  They have been known to oviposite on blueberry leaves, tea leaves (Das), oak leaves, olive leaves, mango leaves, flower heads, and banana fingers.  Species of Eucharitidae are consistent in their choice of leaf for oviposition.
  Because Oraseminae eggs are laid on plants that are not always visited by foraging ants, the larvae will most often attach to intermediate hosts, or “insect prey” that will eventually be devoured by ants.  Sometimes, however, foraging ants are present and there is no need for an intermediate host. Upon arriving at the ants’ brood, the larva burrows into the host's thorax and feeds there.  The wasp feeds until the host larva pupates; after the host pupates, the wasp will resume feeding until it emerges from its host.  The average time of development from planidia to adult is 29.5 days; the average pupal stage is 8.2 days.
  Because Oraseminae larvae, pupae, and adults are easily distinguished from their host, the wasps disguise themselves by passively obtaining the odor of the fire ants.  After a few days in the nest, the odor wears off and the ants begin to notice the wasps are not a part of their brood. At this point, the wasps leave the nest to mate and lay eggs.  Though Oraseminae have a high fertility rate, only a small percentage of eggs survive to adulthood.
caption: Orasema simplex from Argentina
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