Biology Fieldwork

A Level

Catching invertebrates from trees and bushes

Using a sweep net to capture invertebrates in long grass

3. Catching invertebrates from trees and bushes

Invertebrates on trees and bushes

Invertebrates on leaves and stems can move by running or crawling or flying. Be gentle when handling live animals. 

Pooter

A pooter is a flexible tube that can be used to catch invertebrates directly from leaves. The user sucks one end, which draws the invertebrate upwards to a trap area. A barrier, such as a layer of muslin, prevents the user from ingesting the invertebrate. Several designs of pooter are available, but the principle is the same throughout.

Once you have finished collecting invertebrates, you will need to sort the catch, which is much easier if the animals have been anaesthetised or killed. Larger invertebrates can be temporarily stunned by placing the collecting tube in a fridge for 30 minutes. Earthworms cannot be reliably identified to species level in the field, so they will need to be killed.

Kite nets and sweep nets

Kite nets are lightweight nets used for catching insects flying above the vegetation layer. In woodland, they can really only be used in open areas, such as tracks and woodland rides, or above low-growing plants. Use a figure-of-eight motion to move the net, and keep clear of any brambles and thorns that may make holes in the net.

Sweep nets are more robust nets that can be used to disturb non-woody vegetation such as grassland and meadow plants. Use a figure-of-eight motion to move the net just on top of the vegetation. 

Beating tray

Place a white sheet on the ground below the branches of a bush. Use a strong stick to shake the leaves and branches of the bush so that invertebrates fall onto the white sheet. They can be removed from the sheet using a pooter.