Collecting Moths Safely

To collect moths, students will need to build a simple moth trap. To make moth research accessible to as many students as possible, we share a trap design built from 2-liter soda bottles and other readily available materials with a cost of $0.50-$1.00 per trapping night.

Building a Moth Trap

We recommend that teachers practice building a trap themselves to help determine where their students may experience possible difficulties or extra time in trap construction.

SAFETY FIRST: Prior to beginning trap building, teachers should clearly discuss the safe use of scissors used for cutting the plastic bottles as some force is often needed to pierce the plastic. Also, share and enforce any requirement to wear eye protection.

About Pesticide Strip

A solid pest strip that is made to release very small amounts of pesticide vapors over time is used to kill collected moths without damaging them like liquid chemicals do. These can be purchased online or at home and garden centers. (See pesticide safety)

Material List per Trap

  • Two 2-liter soda bottles
    Preferably clear and straight sided, both bottles should be of the same size
  • Cotton/hemp string or yarn
    About 1.5 m (nylon or similar types of string will come unraveled or the knots don’t hold tight – test your string to see how it works prior to student use).
  • Binder clips
    Other clips, spring-type clothespins and pipe cleaner or twist ties can work too
  • Clear packing tape
    Or other tape tested beforehand to ensure its adhesion to plastic
  • Mini UV LED keychain flashlight 395 nm
    1 per trap standard

  • Heavy-duty single hole puncher
  • Small pointed scissors
  • Pesticide Strip
    Hot Shot brand No-Pest Strip2 removed from plastic container and cut into 1 x 1 cm inch pieces 
  • Fiberglass window screen
    Roll this several layers thick around pest strip squares and staple it closed
  • Thin marker
    Use a thin marker to draw lines for cuts on the bottles. Lines to be cut are indicated in red dashes on these diagrams.

Preparing the Trap Components

Lines to be cut are indicated in red dashes on these diagrams.

Bottle One

  1. Make two cuts to Bottle 1 and punch 3 holes equally spaced around FUNNEL. Small funnel opening should be about 5 cm in diameter.

Bottle Two

  1. Make two cuts to Bottle 2 and then a third vertical cut to create a broad panel.
  2. Spread out and make two cuts on the panel to create three equally sized panes.
  3. Punch 3 holes equally spaced around CAP and four holes in the corners of each of the three panels.
  4. Assemble panels as shown and use clear tape on edges to create the triple PANEL assembly.

Assembling the Trap

  • Tie three 45 cm strings to holes in the PANELS.
  • Thread each string, from the inside-to-outside, through the holes in the CAP and tie in a knot at the far end.
  • Use twist ties or pipe cleaner to firmly attach bottom of PANELS to the FUNNEL.
  • Attach LED light source to PANEL using tape, making sure to allow access to the on/off switch.
  • Complete assembly by seating FUNNEL down into the COLLECTION BUCKET and clipping together.

Placing the Trap

  1. Use the string to attach the trap to a tree, building, or other structure several feet off the ground.
  2. Place a safety-protected (with screen) pesticide square in the COLLECTION BUCKET.
  3. Turn on the light source as near to sunset as possible to provide the most battery life. Collect moths each morning and replace pesticide into air-tight containers for re-use.

See additional information on pesticide safety

Moth trap built using instructions provided.  Shown with small keychain UV LED light turned on and ready to attract moths

Pesticide Strip Safety

The pesticide strips used to kill the collected moths contain chemicals that disperse in the air in very small amounts over time and are relatively odorless. Even though you may not be able to smell it, you must limit your skin-to-skin contact and inhalation of vapors in small, enclosed spaces.  If possible, work with the pesticide strip outdoors or in well-ventilated areas.

Depending on the age of your students or school policies, you will need to decide how to provide the pest strip for trapping. Some teachers only handle it themselves and place traps on school property, others arrange for adults to obtain the pesticide from the school, and others will allow students to take the pesticide strip home in well-sealed and labeled containers.  Regardless of the methods, it is important to stress safety in handling the strips. The strips are active for many months if kept in sealed containers and can be reused over time.