Don't be daunted by pinning and spreading your butterfly specimen! Butterfly pinning is a rewarding hobby that will help you learn more about them and add specimens to your collection. Entomology is the science field with the most knowledge added to it by amateurs, there are SO many insects in the world and SO few entomologists, that almost anyone who takes the hobby seriously can add new data. So let's get started!
- dried butterfly
- re-hydrating chamber
- insect pins
- mounting (aka spreading) board
- glassine or wax paper strips
- glass mounting sheets (for butterflies)
- spade tip tweezers
If your butterfly is fresh caught, you can skip the re-hydrating step, but if you purchase a dried, unmounted insect, it WILL break while spreading if you don't re-hydrate it.
The first thing you will need to do is make a re-hydrating chamber. There are numerous ways of doing this and you may need to experiment with different methods to find the one that works best for you. Here at Little Caterpillar, the method we use can be done very easily with household items. Simply take a Tupperware container with a lid, and put a sponge soaked with hot water in the bottom. Cut the corners of the glassine envelope off (this will be the triangle shaped waxy paper your butterfly is in), but leave the butterfly inside. Then wrap each glassine envelope in a damp paper towel. Depending on your climate you may need to add something to prevent mold growth inside, many things from Windex to Dawn soap will help with this.
The amount of time you leave your specimen in the re-hydrating chamber will vary depending on the size of your butterfly, for medium or small butterflies two days will generally be enough, for larger ones (such as Morphos and Birdwings), three days is usually required. If left in any longer they will usually begin to fall apart.
After you believe your specimen is ready gently test the wings by rolling the tip of your finger where the wings meet the thorax. If it is ready the wings should show signs of opening. If not you may need to put it back in the chamber, or you can use a hypodermic needle to inject boiling water into the butterflies thorax to speed the process.
SPREADING THE BUTTERFLY
After your specimen has been re-hydrated, you will need to stick an insect pin through the thorax of the insect. It is best not to use sewing pins as they don't leave room for collecting data and may corrode and damage your specimen. You will want to ensure that all your butterflies are set at the same height on the pins and leave room for you to grab the top of the pin.
Next, pin your insect on your mounting board and use a wax paper strip to hold down the wings on each side. You will then use your spade tip tweezers to gently move the wings into position. You will generally set the bottom edge of the forewing (top wing ) at a 90 degree angle to the body (see image above), and then pull the hind wing gently up, leaving a small opening in the outside corner between the two wings.
As soon as the wings are set in the correct position you will need to place additional wax strips across the wings in order to firmly hold them in place, or an easier option is to use glass plates. It can be difficult to get wings to stay in the position you want using only wax strips, and having the wings continually fall out of place and get pulled pack into place is likely to cause damage. With glass plates you still use one wax strip on each side, position the wings and then set the plate on top. This will ensure their is no sliding or movement and allows you to easily see the wings to double check their positioning is correct.
After the wings are done all you need to do is use a few pins to get the antenna in a position you like (typically a wide 'V' ) and let the butterfly dry*. Drying time varies on the size of the butterflies, most small butterflies will require a week, larger ones two weeks, and birdwings likely 3 weeks. It is better to allow more time than you expect it to take, otherwise even if the wings look good at first, they may start drooping over time if they are not properly dried.
*If you plan on using a butterfly in art and don't want the pin left in, now would be the time to remove it. Use the tweezers to gently put pressure down on the thorax while pulling the pin up. (This part is also easier with glass plates as they put weight down on the wings and make it easier to pull the pin without moving or damaging the wings.)
After letting the butterfly dry for 1 to 3 weeks, very carefully remove the glass slides, pins, and wax paper strips. The wings and antennae will be VERY brittle at this point, and it is easy to have a pin catch an antennae and break it off.