Malaise trap

Definition

A large, tent-like interception trap designed to capture flying insects, particularly effective for Hymenoptera and Diptera. The structure consists of fabric or netting walls arranged with a central barrier; insects striking the barrier fly upward toward the light and are funneled into a killing jar or collecting vessel at the trap's highest point. Invented by René Malaise in 1934, it remains a standard passive sampling tool in insect biodiversity surveys and taxonomic research.

Etymology

Named for Swedish entomologist René Malaise, who invented the device in 1934.

Example

A Malaise trap positioned along a forest edge captured hundreds of ichneumonid wasps and tachinid flies over a one-week sampling period, revealing a diverse parasitoid community not detected by sweep netting alone.

Related Terms

• interception trap
• flight-intercept trap
• pan trap
• pitfall trap
• beating tray
• mercury vapour lamp
• emergence trap
• killing jar

Usage Notes

The Malaise trap is a passive, non-attractant trap that relies on insect flight behavior rather than chemical lures; placement in active flight corridors (e.g., along forest edges, streams, or trails) substantially affects capture rates. The original design used black netting with white roof panels; modern variants employ different colors and materials (PET, nylon) with variable efficacy across insect groups. Often deployed in arrays for quantitative biodiversity studies. Not effective for weak fliers, ground-dwelling species, or strictly nocturnal taxa unless combined with lighting.