Trichogrammatidae

Definition

A family of minute endoparasitoid wasps in the superfamily Chalcidoidea (order Hymenoptera), comprising roughly 840 species in ~80 genera distributed worldwide. Adults are among the smallest insects known, with most species under 1 mm and members of the genus Megaphragma reaching less than 300 μm—approaching the lower size limit for functional insect anatomy. Larvae develop as egg parasitoids within host eggs, primarily of Lepidoptera and other insects.

Etymology

From the type genus Trichogramma (Greek thrix 'hair' + gramma 'mark/writing') + family suffix -idae, referring to the hair-like wing fringes visible in these tiny wasps.

Example

Trichogramma brassicae and T. pretiosum are mass-reared for inundative biological control of lepidopteran crop pests, with females depositing one or more eggs inside host eggs; the resulting wasp larvae consume the developing host embryo before pupating within the egg shell.

Related Terms

• Chalcidoidea
• Parasitoid
• egg parasitoid
• Biological control
• Hymenoptera
• Megaphragma
• Trichogramma
• microhymenoptera

Usage Notes

Sometimes informally called 'trichogrammatids' or 'trichs' in applied entomology. The family's extreme miniaturization—approaching 200 μm in some Megaphragma species—involves novel anatomical reductions, including nuclei that lose their nucleoli during development. Taxonomic identification relies heavily on male genitalic characters and wing venation patterns due to the group's morphological conservatism.