Pinning and Gluing Moths

Pinning insects is a skill used by entomologists to preserve insects in a form where they can be handled and examined under microscopes for identification.  For smaller moths the risk of damaging the moth beyond recognition outweighs the benefits and so we also describe a simple method to glue the moths to cardstock prior to pinning.

Pinning Methods

The typical position of wings in a pinned moth best allows the student researcher the ability to see the upper and lower surfaces of both the front and hind wings to aid in identification. But, even with the best techniques and patience, not all pinned specimens will end up in this preferred position due to intrinsic characteristics of the moth and the moth size.  Some moth wings are just easier to spread than others, but practice will improve the odds of a well-pinned moth.

Important tips

To spread the wings, a “relaxed” or freshly killed moth must be used so this should be done as soon as possible on the same day the moths are collected from the trap. Otherwise, the wing muscles will harden and trying to spread the wings will cause them to break apart. If this happens, moths can still be glued in their dried position to card stock. Some freshly collected moths may still be moving when collected. These can be killed by placing them in a freezer for at least one hour.

Materials needed

  • Foam (e.g. styrofoam) boards 1 to 3 cm thick and approximately 15 x 30 cm. Higher density (“tighter”) foam is preferable (can be purchased or reused from packaging materials)
  • Blank, white index cards or cardstock
  • Insect or sewing pins, approximately 4 cm long (#1 or #2 size insect pins are used by entomologists but regular or stainless steel sewing pins are ok; they will need to be strong enough to pierce index cards without bending)
  • School glue (dries clear)
  • Wax paper or tracing paper cut into strips, approximately 0.5 x 5 cm
  • Small scissors and forceps or tweezers

Pinning and Spreading Wings

Prior to beginning the pinning of moths, teachers should clearly discuss the safe use of scissors and pins that will be used and any requirement to wear eye protection. Care should be used to keep excess pins in containers to prevent loose pins on tabletops and floors.

Step One

Place the moth on the foam board with the top (dorsal) side up and insert pin through the middle of the thorax, keeping the pin as straight as possible in the vertical position.  Insert the pin until 1 cm of the pin remains above the moth thorax. If you have a moth with a large body, cutting a groove in the foam board can be helpful to position the wings flat with the surface of the foam.

Step Two

For the following steps, when moving and positioning the wings, use a pin to gently pull the wings forward (up towards the head) by using the front edge of each wing.  This edge has a thickened vein that can be “gripped” and moved without tearing the surface of the wing.

Pin a strip of wax paper across the left and right wings as shown in the diagram.  The wings should be somewhat flattened but should be able to slide underneath the paper.

Step Three

Pull the forewings forward until the back edge is perpendicular to the body.  If they don’t stay in place under the paper, use another pin through the paper to push it down more firmly. If the paper doesn’t keep the wing in place, you can insert a pin directly through the wing near the front edge vein.  Although this creates a small hole in the wing, it works well; especially so for younger students.

Step Four

Pull the hindwing (again using the front edge vein) forward making sure the front edge is near perpendicular to the body and just underneath the back edge of the forewing.  Add an additional pin to the paper to secure the wings in place.

Step Five

Cut a small piece of paper approximately 1.5 x 5 cm or smaller and write the date, location and student collector’s name(s) and pin near the moth. This allows the student to keep track of the collection data.

Step Five

Moths should be left in this position on the foam board for 3 days to a week (longer times for larger moths) to allow the moth to fully dry.  Once the time has passed, the paper strips can be removed and the moth can be handled by gently lifting the pin now attached through the moth. The collection label can then be pinned below the moth in the same pin to keep the information with the specific moth individual.  

Handle the pinned moth with care by holding the head of the pin only and avoid touching the moth as the wings, antennae, and legs are brittle and can fall off or break easily.

Gluing and Pinning Moths

For each small moth or others that you will not pin with their wings spread, cut from note cards or cardstock a small, blunt triangle approximately 1 x 2.5 cm in length. This triangle is called a “point”.

Step One

Insert the pin through the wide end of the point until 1 cm of the pin remains above the surface. On the narrow end place a small drop of white glue.

Step Two

Using forceps (“tweezers”), place the moth on the glue and position so the head is facing up (“north”).

Leave the moth in position until the glue dries. 

Step Three

Cut a small piece of paper approximately 1.5 x 5 cm and write the date, location and student collector’s name(s) and pin using the same pin the “pointed” moth is on.  This allows the student to keep track of the collection data.