How Insect Exocrine Glands Work

Exocrine glands release a secretion to the body surface or into a lumen and are likely to be found in all insect taxa. Their secretions are diverse, serving many physiological, behavioral, and defensive functions. Much research has characterized gland structure and secretion identity and function, but little research has attempted to understand how these glands work to release secretion amounts in a timescale appropriate to function: How are some (e.g., physiological) secretions released in small amounts over long times, while others (e.g., defense) are released in large amounts infrequently? We describe a qualitative model, comprising intracellular, extracellular, and external compartments for secretion storage; rates of movement of secretion from one compartment to the next; physicochemical properties of secretions; and controlling behaviors, which may explain the release dynamics of secretions from these glands. It provides a template for quantitative dynamic studies investigating the operation, control, release, and biomimetics of exocrine glands.