Scelionidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Hymenoptera
Superfamily: Platygastroidea
Family: Scelionidae

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Summary

Scelionidae is a large family of parasitoid wasps that primarily attack the eggs of insects, contributing to biological pest control. They have a wide range of hosts and exhibit significant diversity in morphology and behavior.

Physical Characteristics

Small wasps, measuring 0.5–10 mm, often black and highly sculptured, with typically elbowed antennae that have a 9- or 10-segmented flagellum.

Identification Tips

Look for the shape and arrangement of the terga; terga 2 and 3 are subequal in length, but if tergum 2 is much longer, then the forewing will have 2 veins.

Habitat

Widely distributed; often found associated with various host insects, particularly at the ends of summer when egg numbers peak.

Distribution

Cosmopolitan; over 3000 described species across approximately 176 genera.

Diet

Egg parasites of insects, including several economically important species, and occasionally other arthropods such as spiders and butterflies.

Life Cycle

Generally idiobiont; they parasitize the eggs of their hosts and often remain near the parasitized eggs until the offspring emerge.

Reproduction

Eggs are laid in the eggs of host insects, which include a variety of species across many orders.

Predators

Natural predators may include other parasitoid wasps or insectivorous animals, but specific predator information is not detailed.

Ecosystem Role

Important role in biological control of pest insects; several species are used in pest management.

Economic Impact

Many species are important in controlling pests such as the spongy moth, migratory locust, and horse flies.

Collecting Methods

Net sweeping
Light trapping
Host egg collection

Preservation Methods

Pinning
Ethanol preservation

Evolution

Originally considered a subfamily of the Platygastridae but subsequently recognized as a distinct family in the Platygastroidea superfamily.

Similar Taxa

Platygastridae

Misconceptions

Some may confuse them with other small black wasps or assume they are harmful to humans, though they primarily parasitize insect eggs.