Petiolate

Definition

Possessing a petiole; having a narrow, stalk-like constriction between two body regions, most commonly the constriction between the mesosoma and metasoma in certain insects or between body segments in some arachnids.

Etymology

From Latin petiolus, diminutive of pes, pedis (foot), via New Latin petiole + -ate suffix denoting possession.

Example

In ichneumonid wasps, a strongly petiolate abdomen creates the characteristic 'thread-waisted' appearance that distinguishes them from more robust vespids.

Synonyms

• stalked
• pedicellate

Related Terms

• petiole
• Sessile
• Pedicel
• wasp-waisted
• constricted waist
• propodeum

Usage Notes

Applied primarily to structures with a narrow, stalk-like connection; contrasts with 'sessile' (directly attached without stalk). In Hymenoptera, describes the degree of constriction at the waist, ranging from slightly petiolate to strongly petiolate (thread-waisted). Sometimes used interchangeably with 'pedicellate' in arachnology for segmented stalks, though 'pedicellate' more often refers to antennae or pedicels specifically. Not used for the botanical petiole of leaves in entomological contexts.