Eucharitidae
Encyclopedia
Eucharitidae is a family of parasitic wasps known as Eucharitid wasps. Eucharitid wasps are members of the superfamily
Superfamily
The term superfamily is used to describe several different concepts in different scientific fields:* Superfamily and Superfamily : a level of biological classification; redirects to Taxonomic rank...

 Chalcidoidea and consist of three subfamilies: Oraseminae, Eucharitinae, and Gollumiellinae. There are 53 genus and 473 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 genera of ant. Furthermore, they are one of the few parisitoids that have been able to utilize ants as hosts, despite ants’ effective defense system against most parisitoids. 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.

Life Cycle

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
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...

 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
Brood
Brood may refer to:* Brood, a collective term for offspring* Brooding, the incubation of bird eggs by their parents* Brood , the young of a beehive*Brood: to think deeply about something, often in a dark or melancholy manner....

; however, sometimes they will attach themselves to other insects, using them as an intermediate host
Intermediate host
A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary 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
Superparasitism
Superparasitism is a form of parasitism in which the host , is attacked more than once by a single species of parasitoid. Multiparasitism, on the other hand, occurs when the host has been parasitized by more than one species....

 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.

Anatomy

Most Eucharitids are between 2.0 and 5.4 mm long and vary from metallic colors to black. They have 13 or less segments on their antennae, but some have up to 26.Heraty, J.M. Family Eucharitidae. (1995) Pages 309-314. in Gauld, I.D.; Hanson, P., Hymenoptera of Costa Rica. Oxford: Oxford University Press. ??

The following is a list of the main anatomical characteristics of Eucharitid wasps.
  • Prepectus lying in same plane as, and fused, to pronotum
  • Pronotum small and hidden by the head dorsally
  • Gaster
    Gaster
    The gaster is the bulbous posterior portion of the metasoma found in Apocrita Hymenoptera . This begins with abdominal segment III on most ants, but some make a postpetiole out of segment III, in which case the gaster begins with abdominal segment IV....

     usually relatively small with a very long petiole
    Petiole
    Petiole may refer to:*Petiole , the stalk of a leaf, attaching the blade to the stem*Petiole , the stem formed by a restricted abdominal segment that connects the thorax with the gaster in the suborder Apocrita...

  • Fore wing with marginal vein moderately long, stigmal and potmarginal veins extremely short
  • Moderately large, about 2.0 to 5.4 mm in length

Subfamilies

The number of Subfamilies of Eucharitidae has changed over the years, but the three most widely accepted Subfamilies are: Oraseminae, Eucharitinae, and Gollumiellinae.

Oraseminae

Oraseminae are parasitic on the ant genus Pheidole (Myrmicinae), as well as the fire ant
Fire ant
Fire ants are a variety of stinging ants with over 285 species worldwide. They have several common names, including ginger ants, tropical fire ants and red ants.- Appearance :...

 in southern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 and the little red fire ant in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

. They are distributed world wide in tropical regions such as Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

, Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, and Argentina. They are also native to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...

, Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...

, 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 larva will most often attach to intermediate hosts, or “insect prey” that will eventually be devoured by ants (Lachaud). Sometimes, however, foraging ants are present and there is no need for an intermediate host. Upon arriving at the ants’ brood, Oraseminae larvae burrow into the host's thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...

 and feed there. The wasps feed 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 that the wasps are not a part of their brood. It is at this point that the wasps leave the nest to mate and lay eggs. Though Oraseminae have a high fertility rate, a small percentage of eggs make it to adulthood.

Eucharitinae

Eucharitinae are parasites of poneromorph ants Ectatommatinae ponerinae and Formicinae
Formicinae
Formicinae is a subfamily within the Formicidae containing ants of moderate evolutionary development.Formicines retain some primitive features such as the presence of cocoons around pupae, the presence of ocelli in workers, and little tendency toward reduction of palp or antennal segmentation in...

, although one genus from Australia is parasitic on the Bulldog ant.

Female Eucharitinae emerge with up to 4500 eggs and begin oviposition soon after emerging from the nest. They deposit their eggs in groups of 8 to 15 on plant buds, on the undersides of leaves or on fruit skin. Eucharitinae attach themselves to foraging ants and do not use an intermediate host. Some species of Eucharitinae, such as Kapala terminalis and Kapala sp., have been known for their jumping capabilities. They stand erect on the plant they hatched on and with out any distinguishable preparation they jump about 10 mm from the leaf onto a foraging ant. The larvae are external parasites of their host, and are not noticed due to their acquisition of the host’s odor. After the wasps are fully developed, they emerge in large numbers. The males swarm around the nest in wait of the females. Mating takes place immediately, and oviposition occurs soon after.

Gollumiellinae

Gollumiellinae are unique in that they hook their eggs onto the plant and connect a ropey secretion to it, which stands erect. This acts as an attraction mechanism for paratrechina
Paratrechina
Paratrechina is an ant genus from the subfamily Formicinae .There are over 150 described species and subspecies, some of which occur on every continent...

 ants. Gollumiellinae larvae burrow into the host's thorax and feed there. The rest of its life cycle is similar to the aforementioned life cycle of Eucharitids.

Biological Control

Eucharitids are candidates for biological control because each Eucharitid Subfamily targets a specific variety of ant genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

. On the other hand, some Eucharitids, including the Kapala genus, are classified as pests for several different resons. First, a few days after oviposition
Oviposition
Oviposition is the process of laying eggs by oviparous animals.Some arthropods, for example, lay their eggs with an organ called the ovipositor.Fish , amphibians, reptiles, birds and monetremata also lay eggs....

 occurs the leaves dry up where each egg was located. Second, it has been reported that tealeaves with such marks do not have as strong of a flavor as tea leaves without these marks. Third, not all Eucharitids have a significant effect on the size of their host’s colony.

Orasema are sometimes used as means of biological control for many ants, including the fire ant and little fire ant. This is because pesticides can cause damage to the environment, and they do not always work on fire ants. In addition, there are at least two Eucharitid species groups that are specialized parasites of these ants. In a journal, Heraty stated, “Leaving aside the philosophical problems associated with introducing any organism for biological control, I believe that species of Orasema do have potential as biological control agents and deserve more study.”

Additional References


External links

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