Insect Collecting

- Catching insects -

Summary: Insect collectors use a few simple tools and supplies. Sweep and/or butterfly nets allow you to capture flying insects in their natural habitat. Pit-fall traps can be used to collect insects that crawl along the ground.

Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)

Capturing insect specimens

This is part 1 of a two part series on making an insect collection. We'll first cover some basic tools for capturing specimens in good condition, then look at ways to Prepare and Display an Insect Collection. The information is geared mostly for kids, with adult supervision, but will work for gardeners as well that might want to make a reference collection.

Please note - the following describes some procedures that may be dangerous if done carelessly. Children should only perform these activities with adult supervision.

sweep nets

Collecting insects with sweep nets. Photo by Jack Dykinga, USDA/ARS


The tools of the insect collector are pretty simple and inexpensive. Your collecting kit should include:

  • insect (butterfly & sweep) nets
  • magnifier (hand lens)
  • insect killing jars
  • vials, alcohol, index cards, pencil
  • plastic cups and propylene glycol-based antifreeze
  • insect field guide(s)

Wards Natural Scientific is a good source of insect collecting and curating supplies. They sell insect nets, insect pins of all sizes, display boxes, Cornell drawers, unit trays, spreading boards, vials, ethyl acetate, and so forth.

Insect nets

Insect nets come in different sizes and fabric weights depending on the intended use. Sweep nets are made of heavier fabric and are used to sweep through vegetation. Butterfly nets are made of light weight fabric and are used to snatch flying insects out of the air. Nets can be homemade, if you have some sewing skills, or can be purchased online.

Insects caught in the net can be placed directly into a killing jar (see below) by either inserting the jar into the net and capturing the specimen against the net cloth or by trapping the specimen at the bottom of the net and placing this end into the jar and screwing on the lid.

A hand lens magnifier should be standard equipment for every insect collector and gardener. Get one that is 10x power, or less, and a large diameter -- 3/4" or larger. Magnifications over 10x are difficult to use (see Using a Hand Lens).

Making an insect killing jar

Killing jars are used to kill insect specimens in the field when no freezer is available. The best way to kill an insect specimen is to put it in a freezer overnight. Freezing preserves colors and delicate parts that might otherwise be broken. Once thawed the specimen can be pinned. If you are out in the field, with no freezer handy, the next best way is to use a killing jar.

Wrap a wide-mouth glass jar (~8 oz) in clear packing tape so if the glass breaks it won't shatter. The jar should have a tight-sealing lid. Mix up some Plaster-of-Paris (available from paint stores) to the consistency of a milkshake. Cover the bottom of the jar to about 3/4" with plaster, allow to harden. Place a few drops of ethyl acetate (some nail polish removers are nearly  100% ethyl acetate, check the label, don't use those made from acetone) on the plaster and add a square of tissue paper to absorb excess moisture. This is the basic killing jar. Insects placed inside the jar will quickly die because of the vapors. The jar will need to be periodically recharged with ethyl acetate.

Collecting vials

Vials (4 dram) filled with alcohol can be used for small or delicate insects. Ethyl alcohol (70%) is the best preservative but may be difficult to find (140 proof gin and vodka are 70% ethyl alcohol). Rubbing alcohol (70% isopropyl alcohol) can be substituted. Rubbing alcohol tends to harden specimens making them more difficult to handle later. Collecting information such as date and location should be written on a small piece of index card, in pencil, and placed inside the vial. Pencil lead will not wash off in alcohol.

Pitfall traps

Making a pitfall trap -- Pitfall traps are a great way to collect insects that crawl around at ground level, often coming out only at night. You'll need some propylene glycol-based antifreeze like Sierra brand antifreeze. Do not use antifreeze that contains ethylene glycol because it is poisonous to wildlife and pets.

Get some 8 oz plastic cups. Dig a pit deep enough to bury the cup up to the rim. Pour about an inch of antifreeze (diluted 50% with water) into the cup and fashion a cover that allows crawling insects to enter the trap but excludes entry from above. A small plastic plate supported by rocks, and weighted down with a rock, makes a good cover. Check the trap at least once a week. Antifreeze can be re-used after straining out the specimens. Transfer specimens to a labeled vial of alcohol.

Collect, Collect, Collect

Collect from as many different habitats as possible. You'll find different insects in a grassy meadow compared to the forest, for example. Or, you might restrict collecting to one habitat but vary it over time, by season for example. Also, don't forget to take along your camera to document the habitat.

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