Scelioninae

Haliday, 1839

Genus Guides

Scelioninae is a large of in the Scelionidae, containing over 3,000 described across approximately 160 . These wasps are exclusively parasitoids, primarily attacking the of insects, spiders, and other arthropods. They are generally idiobionts—parasitoids that prevent further development after attack—and several genera have evolved winglessness or adaptations for aquatic environments, including underwater attack of insect eggs.

Calotelea by (c) Stephen Thorpe, some rights reserved (CC BY), uploaded by Stephen Thorpe. Used under a CC-BY license.

Baeus by (c) Stephen Thorpe, some rights reserved (CC BY), uploaded by Stephen Thorpe. Used under a CC-BY license.

Baeus by (c) Tom, some rights reserved (CC BY), uploaded by Tom. Used under a CC-BY license.

Pronunciation

How to pronounce Scelioninae: //ˌsɛliˈoʊnɪni//

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Identification

Distinguished from other platygastroid by combination of geniculate with 9- or 10-segmented , absence of distinct facial ridges present in Teleasinae, and general body plan. Within Scelioninae, are distinguished by wing presence/absence, structure, and metasomal segmentation. -level identification requires examination of microscopic sculpturing, setation patterns, and genitalic structures.

Images

Appearance

Mostly small ranging 0.5–10 mm in body length. Typically black in coloration with highly sculptured . are geniculate (elbowed) with a 9- or 10-segmented . Some exhibit winglessness. Body form varies from slender to robust depending on genus.

Habitat

Extremely diverse: terrestrial worldwide, with some adapted to intertidal zones and underwater . Found in agricultural including rice fields, forests, grasslands, and maritime shorelines. Several genera are wingless and associated with ground-dwelling .

Distribution

distribution spanning all major biogeographic regions. Particularly diverse in tropical and subtropical areas. Documented from North and South America, Europe, Africa, Asia, Australia, and Pacific islands. Specific show varied patterns: some are widespread (e.g., Scelio), others restricted to particular regions (e.g., Chromoteleia primarily Neotropical with one African relict ).

Host Associations

insect eggs - primary across orders including Orthoptera, Lepidoptera, Hemiptera
spider eggs - including maritime spiders in intertidal zones
butterfly eggs - e.g., hackberry emperor documented

Life Cycle

Development is idiobiont: females lay in eggs, larvae consume host contents, and emerge from the consumed egg. Specific developmental durations vary by and environmental conditions but are generally rapid, with multiple possible annually in favorable climates.

Behavior

Females locate through chemical and tactile cues. Several exhibit winglessness in females, males, or both sexes, correlating with ground-dwelling host association. Some have evolved underwater oviposition, with females submerging to attack aquatic insect eggs. Maritime species such as Echthrodesis lamorali enter torpor when submerged, using a physical gill formed over the body surface.

Ecological Role

Significant regulators of through . Important agents in agricultural systems, particularly against pest Orthoptera and Lepidoptera. In rice of southern India, Scelioninae constitute a major component of diversity. Maritime represent rare examples of intertidal parasitoid wasps.

Human Relevance

Used in classical and programs against agricultural pests. Several are commercially produced or studied for control of grasshoppers, crickets, and pests. Taxonomic research on Scelioninae has clarified species boundaries and resolved synonymies, improving identification for applied purposes.

Similar Taxa

TeleasinaeFormerly classified together; distinguished by facial ridges and different antennal structure
PlatygastrinaeRelated in Platygastridae; typically smaller with different wing venation and associations often involving gall midges
CeraphronoideaSuperficially similar small ; distinguished by wing venation and mesosomal structure

More Details

Taxonomic History

Formerly treated as Scelionidae, reclassified as of Platygastridae in 2021. Previously also treated as subfamily of Platygastridae s.l. before family-level elevation of Scelionidae.

Morphological Diversity

Tyrannoscelio exhibits extraordinary elongate and expanded frontal shelf; Huddlestonium has uniquely 13-merous female ; Aneuroscelio lacks wing entirely.

Conservation Status

Not assessed as a group; individual of conservation concern include Echthrodesis lamorali, effectively conserved within Table Mountain National Park, South Africa.