Megastigmus pistaciae

Definition

A species of chalcid wasp in the family Torymidae, described by Walker in 1871. A seed-feeding parasitoid whose larvae develop inside the drupes of pistachio (Pistacia spp.) and related Anacardiaceae, making it a significant pest of commercial pistachio cultivation and a subject of study in agroecology and biological control.

Etymology

Megastigmus: Greek megas (large) + stigma (mark/spot), referring to enlarged stigmal veins in the forewing; pistaciae: Latin genitive of Pistacia, the host plant genus.

Example

Megastigmus pistaciae females oviposit through the fruit wall of developing pistachios, and the resulting larval feeding causes kernel damage and nut drop; management in orchards may involve parasitoid conservation or resistant cultivar selection.

Synonyms

• Walker, 1871

Related Terms

• Torymidae
• Hymenoptera
• seed parasitoid
• agroecosystem pest
• Pistacia

Usage Notes

Distinguished from congeneric Megastigmus species by host association and subtle morphological characters; populations vary regionally in voltinism and host range. The species epithet is sometimes misspelled 'pistachiae' in older literature.