What is a Malaise Trap?

A Malaise trap is an effective collecting tool used for scientific research, particularly to carry out biodiversity inventories. Invented by the Swedish entomologist René Malaise in 1934, it resembles a black and white tent with a mesh panel running along its central axis.

trap dimensionsWhen insects encounter the black mesh panel, most will naturally go up towards the white coloured roof in an attempt to escape. The insects are directed to the apex of the trap (trap head) where they encounter a collection bottle and become permanently trapped. The collection bottle is filled with ethanol to preserve the organisms and their DNA. The trap can be deployed indefinitely, with only the bottle replaced periodically (usually once a week), making it a very low maintenance and low cost sampling technique.

A Malaise trap is generally placed in a natural flyway where it can easily collect hundreds of insects in a week. It is a very effective sampling device for many groups of insects — particularly flies, wasps, and true bugs — and can provide a very detailed understanding of local biodiversity.

Furthermore, because it can be deployed in a highly standardized way, the Malaise trap can be utilized for bio‐monitoring programs that seek to track both long‐term trends as well as the impacts of development or restoration activities on species diversity.

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