Natural Polyesters: Dufour's Gland Macrocyclic Lactones Form Brood Cell Laminesters in Colletes Bees

Area of Science:

• Biochemistry
• Materials Science
• Entomology

Background:

• Bees in the genus Colletes construct subterranean brood cells.
• These cells are lined with a protective, waterproof membrane.
• The composition and formation of this membrane were previously unknown.

Purpose of the Study:

• To identify the chemical composition of the brood cell membrane in Colletes bees.
• To elucidate the mechanism of membrane formation.
• To propose a classification for this novel biomaterial.

Main Methods:

• Analysis of the secretion from the Dufour's gland of Colletes bees.
• Chemical characterization of the membrane components.
• Investigation of the polymerization process.

Main Results:

• The brood cell membrane is a polyester primarily composed of 18-hydroxyoctadecanoic acid and 20-hydroxy-eicosanoic acid.
• These fatty acids are stored as lactones in the Dufour's gland.
• The membrane is formed through a polycondensation reaction of the glandular secretion.
• This represents the first documented instance of a naturally occurring linear polyester.

Conclusions:

• Colletes bees produce a unique, naturally occurring linear polyester for brood cell construction.
• The Dufour's gland is the source of the precursor molecules for this biopolymer.
• The proposed term 'laminester' is introduced for this class of layered ester compounds.