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Pitfall Traps

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Time: 2 Class periods Setting: Schoolyard Guiding Questions: Which ground dwelling insects live in this area?
Overview Type of Organism: Invertebrates Habitat: All Materials:
  • 1L soda bottle cut in half with the top inverted like a funnel
  • Plastic or aluminum trays
  • Hand trowel or shovel
  • Bait (sugar, plants or decomposing leaves) (optional)
  • Aluminum flashing or garden edging (option B)
  • Ethyl alcohol to preserve specimens (optional)
  • ID guides. See leaflitter.pdf

How-to video on setting up pit-fall traps

  1. Prepare the bottles by cutting and inverting the top of the bottle. If you would like to preserve the specimens, pour ethyl alcohol into the bottom of the bottle. Place bait on bottom of bottle if desired.
  2. Choose a spot to set up pitfall traps. In a field, under a bush etc. Can do along a transect if desired.
  3. Dig a hole and place plastic cup inside it so that the top of the cup is flush with the ground, fill in soil around the cup so there are no gaps around the cup.

Option 1 

  • Place 3 or so rocks or sticks around the trap and lay the cover on the rocks. Weight the cover with rocks. Se sure to leave enough space between the ground the cover for invertebrates to enter.
  • Leave for at least 24 hours.

Option 2

  •  Install flashing an inch or so into the soil, in 3 straight lines from the cup. This drft fence increases the sample area and increases the number of organisms caught. You can also place a pitfall trap at the end of each of the 3 fences.
  • Tape tray or cover over the bottle, onto the aluminum flashing (to prevent rainwater from entering trap)
  • Leave for at least 24 hours.

Alcohol Safety

  • Contact with the eyes can cause considerable irritation. Wear safety glasses.
  • Very flammable
  • Check that ventilation is good
  • Eye contact: Flush the eye with plenty of water.
  • Skin contact: Wash off with water.
  • If large quantity swallowed: call for medical help