Method #7: pitfall trap

A pitfall trap is designed to catch ground dwelling invertebrates. It's a pit that invertebrates fall into. Hence pitfall.

The trap consists of a plastic cup, jam jar, drink bottle with top cut off or some other suitable open topped container.

Half fill your container with water, and add a few drops of detergent (e.g. dish washing liquid) to break the surface tension. Otherwise, smaller insects may land on the surface of the water and fly off.

Dig a small hole, just bigger than the container. Place the container in the hole (without the lid!).

Carefully fill in the remaining space around the beaker with earth. Make sure the top is flush with the ground (or a few millimetres below) and firm and smooth the soil so that it is level leading into pot. Even the slightest lip above the ground can stop invertebrates falling in to your pit.

It's a good idea to make a cover to keep rain, leaves and birds from eating your catches. The cover should be open on the sides, but covered above. That way, ground dwelling invertebrates are free to fall in, but rain (and birds) coming from above are blocked.

You can use a plastic ice cream lid to make a roof for your pitfall trap. To make a the legs you can either use wire to make 2 loops to pin the ice cream lid over your pitfall trap. You may have a spare wire coat-hanger you can use. Another way is to cut holes in the corners of your plastic lid and use clothes pegs as legs.

Leave your trap out until you have collected 3 different specimens >5mm (1/5th inch) in length.

When you have finished trapping remove your trap and put soil back in the hole!

Mike Bowie (@ecoman) has made a YouTube video explaining what to do.

Posted on April 25, 2020 01:55 AM by jon_sullivan