''Euplectrus'' is a genus of hymenopteran

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s of the family

Eulophidae The Eulophidae are a large family of hymenopteran insects, with over 4,300 described species in some 300 genera. The family includes the genus '' Elasmus'', which used to be treated as a separate family, "Elasmidae", and is now treated as a su ...

. ''Euplectrus'' is a cosmopolitan genus and are easily distinguished from other members of the subfamily

Eulophinae Eulophinae is a subfamily of wasps in the family Eulophidae which includes over 90 genera. Genera The genera included in Eulophinae are: *'' Alibertia'' Risbec, 1951 *'' Alophomorphella'' Girault, 1913 *'' Alophomyia'' Ashmead, 1904 *''Alv ...

by three characteristics i.e. the hind tibial spurs are very long and strong with the longest spur being no less than half as long as hind tarsus and is used to anchor the female wasp to the dorsum of the host caterpillar during oviposition; the scutellum has no lateral grooves or pit-rows; and

propodeum The propodeum or propodium is the first abdominal segment in Apocrita Hymenoptera ( wasps, bees and ants). It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is ...

has a single strong median carina. It is a morphologically conservative genus and the species vary slightly from one another and this creates difficulties in identifying the species. ''Euplectrus'' wasps have been found as parasitoids on the caterpillars of the families Erebidae, Euteliidae,

Geometridae The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek ''geo'' γεω (derivative form of or "the earth"), and ''metr ...

Lasiocampidae The Lasiocampidae are a family of moths also known as eggars, tent caterpillars, snout moths (although this also refers to the Pyralidae), or lappet moths. Over 2,000 species occur worldwide, and probably not all have been named or studied. It i ...

Noctuidae The Noctuidae, commonly known as owlet moths, cutworms or armyworms, are a family of moths. They are considered the most controversial family in the superfamily Noctuoidea because many of the clades are constantly changing, along with the othe ...

Nolidae Nolidae is a family of moths with about 1,700 described species worldwide. They are mostly small with dull coloration, the main distinguishing feature being a silk cocoon with a vertical exit slit. The group is sometimes known as tuft moths, aft ...

Notodontidae Notodontidae is a family of moths with approximately 3,800 known species. The family was described by James Francis Stephens in 1829. Moths of this family are found in all parts of the world, but they are most concentrated in tropical areas, esp ...

Sphingidae The Sphingidae are a family of moths ( Lepidoptera) called sphinx moths, also colloquially known as hawk moths, with many of their caterpillars known as “hornworms”; it includes about 1,450 species. It is best represented in the tropics, ...

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 gen ...

. The larvae of all species of ''Euplectrus'' are greenish-yellow and are very obvious on the host caterpillar's cuticle to which they are very firmly attached. The parasitized caterpillars feed and remain active but stop growing and moulting. The larvae of the wasps in the genus ''Euplectrus'' are external parasitoids of the

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

s of various species of Lepidoptera. They are normally gregarious, laying between five and several hundred eggs per host caterpillar, although a few species lay a single egg on each host. Some species paralyse the host while others do not but in all cases the female injects the host with venom prior to oviposition. The venom stops the host from going through

ecdysis Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnan ...

, as the wasp larvae would be shed with the moulted cuticle and eventually causing the caterpillar to die, although the wasp larvae will have fully developed and spun a cocoon by that time. The eggs are positioned under the host's cuticle but above the hypodermis each egg has a pedicel with an anchor at its end which fastens the egg to the host. The eggs are normally laid on the back of the caterpillar and the larvae stay at the laying site until they complete their development sucking on the caterpillar's

haemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

. When they have completed their growth they migrate to the underside of the caterpillar and spin a loose cocoon in which they

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

te, in some species the larvae spin communal cocoons around the dying host. The ability of ''Euplectrus'' larvae to spin cocoons is unique among the

and the silk which forms the cocoon is produced in modified malpighian tubules and is exuded from the anal opening. The larva undergoes 3–5 molts before pupation and the development from oviposition to

imago In biology, the imago (Latin for "image") is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the imaginal stage, the stage in which the insect attains maturity. It follows the fi ...

is normally no longer than two weeks.

References

Key to Nearctic eulophid genera

Universal Chalcidoidea Database
{{Taxonbar, from=Q5410829 Eulophidae