''Copidosoma'' is a genus of

chalcid wasp Chalcid wasps (, , for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, m ...

s, which are

parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

. The wasps are

polyembryonic Polyembryony is the phenomenon of two or more embryos developing from a single fertilized egg. Due to the embryos resulting from the same egg, the embryos are identical to one another, but are genetically diverse from the parents. The genetic differ ...

, depositing one or two eggs into their host which then develop into multiple offspring and have a soldier caste and a reproductive caste.

Species and biology

''Copidosoma'' has over 200 species, according to the Natural History Museum of London's Universal Chalcidoidea Database. Among these is '' Copidosoma floridanum'', known for having the largest recorded brood of any

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

al insect, at 3,055 individuals, and for having its genome sequenced by the Human Genome Sequencing Center as part of the i5K project. They are mainly

s of the

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s of

and have been deliberately introduced into many areas as biological control agents for agricultural pests, e.g. ''Copidosoma floridanum'' was introduced to

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

to control the tomato looper (''

Chrysodeixis chalcites ''Chrysodeixis chalcites'', the tomato looper or golden twin-spot moth, is a moth of the family Noctuidae, subfamily Plusiinae. It mainly lives in southern Europe, the Levant and tropical Africa, but can be seen migrating across much of Europe. I ...

'') while '' Copidosoma koehleri'' is used extensively in control of the potato tuber moth ('' Phthorimaea operculella'') and '' Copidosoma primulum'' has been used in China to control the cotton bollworm (''

Helicoverpa armigera ''Helicoverpa armigera'' is a species of Lepidoptera in the family Noctuidae. It is known as the cotton bollworm, corn earworm, Old World (African) bollworm, or scarce bordered straw (the lattermost in the UK, where it is a migrant). The larvae ...

'') in wheat crops. The wasps of the genus ''Copidosoma'' are also of interest because they are polyembryonic, i.e. more than one embryo can be found in a single egg, and they have developed a caste system where an embryo can develop into a reproductive adult or a soldier

caste A caste is a Essentialism, fixed social group into which an individual is born within a particular system of social stratification: a caste system. Within such a system, individuals are expected to marry exclusively within the same caste (en ...

. The wasp lays its egg into the host moth's egg and after the caterpillar hatches it undergoes a number of

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

stages until it reaches its final instar and during this time the wasp's egg produces as many as 3000 embryos through cloning, these form an assemblage called a polymorula and live as endoparasitoids in the host. In a study on ''C. floridanum'' 24% of the members in the polymorula, of either sex, develop in to soldiers and when the host is killed in its final instar these soldiers die too while their siblings consume the host and pupate to emerge as adults around two weeks later. Like other Hymenoptera the females are produced from fertilised eggs and the males from unfertilised eggs, female eggs produce a higher number of soldiers throughout development while male eggs produce fewer and only in the later stages of the cycle. Where there is more than one brood, where more than one egg has been laid in a host the soldier caste from the first female brood will kill all any larvae from subsequent eggs laid, except that if a male brood is older and from a different mother then the females will co-exist with the males. It appears that the early emerging female soldiers purpose is inter-specific competition, they ensure that the first female brood has the host to themselves by killing other non related and females and related and younger males, while the later soldiers are produced to defend the host from intra-specific competitors and are produced by both sexes, although male soldiers of ''C. floridanum'' lack aggression and their production may be a trait which is being selected against. Most species of this genus are quite host specific and use a few species of moth as their hosts and phylogenetic analysis indicates that the more closely related the species of wasp are to one another the more similar the species of host selected tend to be. For example the wasps of the species group named after '' Copidosoma cervius'' are all parasitoids of moths in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Geometridae The geometer moths are moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyleti ...

while those in the ''nacoliae'' species group attack caterpillars of the families

Pyralidae The Pyralidae, commonly called pyralid moths, snout moths or grass moths, are a family of Lepidoptera in the ditrysian superfamily Pyraloidea. In many (particularly older) classifications, the grass moths (Crambidae) are included in the Pyr ...

and

Tortricidae The Tortricidae are a family of moths, commonly known as tortrix moths or leafroller moths, in the order Lepidoptera. This large family has over 11,000 species described, and is the sole member of the superfamily Tortricoidea, although the genu ...

Others of note

* '' Copidosoma thebe'' (Walker, 1838) senior synonym of ''Litomastix claviger'' Mercet, 1921

Species and biology

Others of note

Species

References

External links