Entomological Techniques for Insect Collection
This article explores several effective methods used by entomologists to collect insects.
Hunt by Sight
This is the most common method, as the name suggests, involving capturing whatever comes into view.
Cutting
This method entails mowing grass using a specific net with a 1.5 m long handle, a 60 cm diameter net frame, and a sturdy white fabric bag about 50 cm deep. Grass is mowed swiftly, and the bag's contents are checked every 4-5 mows to prevent insects from escaping or perishing. This approach allows for the discovery of various insects: Hymenoptera, Hemiptera, Coleoptera, Lepidoptera, and Arachnids.
Berlese Funnel
This method, alongside sieving, is ideal for finding small insects hidden in litter. A 2-3 cm piece is cut from the bottom of a plastic bottle (such as a Coca-Cola bottle), and two holes are made just below the cut for hanging a wire. The bottle is filled with litter (e.g., tree cavities, undergrowth, and ground under hay bales) and a vial of water and salt is fitted into the opening instead of a cap. A securely fastened net covers the bottle, which can be hung outside in sunlight or placed in a cellar under a lamp. This method is effective for finding intriguing beetles like Pselaphids, endogeous Carabids, and Scydmenids, as well as rare endogeous Hymenoptera like Embolemus ruddii.
Screening
Similar to the Berlese funnel, this method involves collecting debris, sifting it with a 5 mm mesh sieve to retain fine particles and capture larger animals. The fine debris is then placed in another sieve over a basin of water and salt, allowing for the capture of the same animals as the Berlese funnel.
Branch Beating
This technique involves striking branches of various tree species over a white cloth or umbrella placed underneath to dislodge insects. The cloth is checked every 3-4 strikes to prevent insects from flying away. This method is most fruitful early in the morning or at dusk when insects rest on branches and are less reactive.
Wood Inspection for Xylophagous Insects
This method involves inspecting live tree wood for larvae, pupae, and adult insects and their parasites. Infested wood is examined using a sharp knife or axe, with larvae collected and housed in small containers or large containers with compartments containing some of the same wood shavings found in the galleries. Collected wood should be stored in opened containers to prevent deadly mold formation.
Barking
This involves peeling the bark from live or dead trees where many nocturnal insects take refuge. This method is most productive in winter when insects hibernate under the bark of Eucalyptus trees.
Excrement Inspection
This method involves examining mammalian feces, such as cow or goat droppings, by either digging into the feces or placing it in a bucket of water to disintegrate and reveal insects. Remember to check under the excrement, as beetle galleries may be present.
These methods enable the collection of various insects associated with dung, including Geotrupini, Scarabaeini, Aphodiini, Histeridae, and Staphylinidae.
