Scent gland

Definition

An exocrine gland that produces semiochemical secretions—typically pheromones, allomones, or defensive compounds—used for intraspecific or interspecific chemical communication. In arthropods, scent glands occur in diverse body locations (abdominal sternites, metathoracic segments, mouthparts, or leg bases) and serve functions including mate attraction, alarm signaling, trail marking, aggregation, and chemical defense. Secretions may be emitted as sprays, smeared residues, or volatile releases, often accompanied by specialized evaporative structures or grooming behaviors to distribute the signal.

Etymology

From English 'scent' (odor, from Latin sentire 'to perceive, feel, smell') + 'gland' (secretory organ, from Latin glans 'acorn')

Example

The metathoracic scent glands of stink bugs (Pentatomidae) discharge defensive allomones from paired reservoirs when the insect is disturbed; in contrast, the abdominal scent glands of male silkworm moths (Bombyx mori) release the long-range pheromone bombykol to attract females.

Synonyms

• odoriferous gland
• semiochemical gland

Related Terms

• Pheromone
• Exocrine gland
• osmeterium
• stink gland
• Dufour's gland
• mandibular gland
• chemical ecology
• Semiochemical

Usage Notes

Specialists often distinguish 'scent gland' (broad, functional) from more specific terms like 'stink gland' (defensive) or 'morphological gland names' (e.g., Dufour's gland, mandibular gland). In Heteroptera, 'scent gland' usually refers to metathoracic defensive glands, while in Lepidoptera it often indicates abdominal pheromone glands—context determines whether defense or communication is emphasized. Not all odor-producing structures are true glands; some are modified cuticular areas or evaporative surfaces associated with glandular secretions.