Crown Wasps

Stephanidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Hymenoptera
Superfamily: Stephanoidea
Family: Stephanidae

Pronunciation

How to pronounce Stephanidae: //stɛfəˈnɪdiː//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Stephanus linearis by the Smithsonian. Used under a CC0 license.

Stephanus nigripes by the Smithsonian. Used under a CC0 license.

Megischus californicus by the Smithsonian. Used under a CC0 license.

Stephanus hirsutus by the Smithsonian. Used under a CC0 license.

Summary

The Stephanidae, or crown wasps, are a family of parasitoid wasps characterized by a distinctive crown-like structure around the ocellus and modified morphology for parasitizing beetle larvae. They are rare and poorly understood, with only a fraction of species described from multiple specimens.

Physical Characteristics

5-19 mm in length with slender antennae having 30 or more segments. Has a crown of teeth around the median ocellus and a long ovipositor. Modified pronotum and highly modified hind legs with swollen hind femur having large teeth on the underside and distinctly widening tibiae. Largest species can reach up to 35 mm in length.

Identification Tips

Notable for the ocellar corona, which is a semicircular to circular set of projections around the middle ocellus, forming a 'crown' on the head.

Habitat

Primarily associated with forests, particularly those with wood-boring beetles and horntails. Most commonly found in subtropical and moderate climate zones, especially in western and southern regions of their distribution.

Distribution

Cosmopolitan, with global diversity more concentrated in subtropical and moderate climates. Most diverse in western and southern regions; only two species found in the eastern areas of North America.

Diet

Parasitoids of xylophagous beetle larvae, mainly targeting the families Cerambycidae and Buprestidae, with some instances of parasitism on Curculionidae and hymenopteran hosts.

Life Cycle

Undergoes complete metamorphosis; adults are often rare and have close to 95% of species described from single specimens.

Reproduction

Reproduces by laying eggs in or on the larvae of their host beetles, leading to the death of the host through the parasitoid's life cycle.

Predators

Specific predator information is not detailed; however, as with many insects, they can be susceptible to generalist predators in their habitat.

Ecosystem Role

Acts as a biological control agent by parasitizing beetle larvae, particularly wood-borers which are significant in forest ecosystems.

Economic Impact

Known for their role in biological pest control; some species are used specifically against pests that inflict damage on economically important plants, such as eucalyptus.

Collecting Methods

Using insect nets to capture adults during host tree inspections
Baiting with suitable hosts to attract adults

Preservation Methods

Pinning specimens for taxidermy
Using alcohol to preserve specimens

Evolution

Considered one of the most basal groups of hymenopterans, representing early diversification within the suborder Apocrita. Genus-level diversity has remained relatively stable since the Late Cretaceous based on fossil evidence.

Similar Taxa

Misconceptions

Often confused with other parasitic wasps due to superficial similarities, particularly with the Ichneumonoidea superfamily.