MadSci Network: Zoology |
Dear Ericka,
Thank you for your question on preserving insects. The study of insects
is called entomology, and the people who study insects are called
entomologists. Entomologists have developed ways to preserve insects to
maintain the specimen's value for scientific study, as well as ways to
display insects for their beauty. I will briefly describe the main
methods of preserving insects, and then also give you references that you
can use to start collecting insects on your own.
Pinning
The most traditional method of preserving and displaying insects is with
the use of special pins. The entomology pins come in different widths to
be used on different sized insects. (The bigger the insect, the bigger
the pin can be.) In general, entomologists insert the needle through the
right side of the insect's upper abdomen. This pinned insect is then
placed inside a collecting box (which I will describe below) or display
case, with the tip of the pin embedded in cork board or Styrofoam.
Beetles, grasshoppers and wasps can be easily pinned. The pins can be
easily removed from the box and traded with fellow entomologists. These
are much cooler than baseball cards!
Spreading
Spreading is used for insects with large wings. The technique is the same
as pinning, but care is taken to fix the wings in a good position.
Spreading is done with the aid of a spreading board. (Spreading
boards are a common possession of insect collectors, and can be purchased
from any biological supply company.) The insect in pinned in the middle
of the spreading board soon after it is killed, and the wings are held to
the sides of the board with strips of paper for several days. After
several days, the strips of paper are removed from the wings, which will
have become hardened in place. Butterflies, moths, dragonflies, and even
grasshoppers and beetles can be spread in order to better display their
wings. My best friend is great at spreading insects. He is patient with
placing the wings in just the right position before securing them in
place, and then lets them harder for a week before carefully removing the
insect from the pinning board. For my birthday he gave me a pretty Rosey
Maple Moth from his collection which had been spread using a spreading
board.
Pointing
While there are special ways of pinning small insects using complicated,
tiny pins, many entomologists prefer to point any insect that would break
if a normal sized pin was used. To point an insect, first you must cut
out a small triangle of stiff paper. A pin is passed through the center
of the triangle, and the insect is glued onto the longest tip of the small
triangle. In this way, the paper serves as a bridge between the insect
and the pin, which is placed in collecting boxes with regularly pinned
insects. One great tip is to use clear nail polish instead of glue for
your best specimens. Small beetles and flies are often pointed. I have
always liked working with small flies. It takes practice to be able to
point an insect without getting glue or nail polish all over the fly's
wings and legs. Because many entomologists get irritated with pointing
such small insects, I have been able to trade some of my pointed flies to
others for really interesting insects that they've pinned. (I aquired an
amazing Tiger Beetle through just such a trade.)
Slides
For very small insects, slides are the best option for preserving them.
The specimen is placed on the glass slide, and then a drop of glue is
placed over it. A glass cover slip is then put on over the insect and
glue, and allowed to dry. Some insects are best seen if they are prepared
with special chemicals first to make it easier to see through them.
Fleas, lice, and other tiny insects can be preserved on slides. Medical
entomologists tend to be the ones that have insects preserved on slides.
Because slides are difficult to keep in a collecting box, other
entomologists don't tend to carry them around. Because so few
entomologists have insects preserved on slides, you can look really cool
when you show off your slides to friends.
Alcohol
For insects that would shrivel up if allowed to dry, alcohol is used to
preserve them. Usually 70% ethanol is the alcohol used, but other
alcohols will work also. The insect can be dropped straight into the
water-tight vial with alcohol. Because this method is so easy, some
entomologists will even use alcohol to preserve insects that would
normally be pinned or pointed. Alcohol is used to preserve soft bodied
insects such as termites, caterpillars, and grubs. Termites are among the
most interesting organisms ever. (That is almost a scientific fact.) One
of the most impressive collections I've seen is owned by the Audubon Institute down here in
New Orleans. They caught thousands and thousands of termites as they
swarmed one night in the French Quarter, and then dunked the lot of them
in a giant container of a liquid preservative, which is probably alcohol.
Mounting
Mounting is an easy way to display your beautiful and interesting insects
that doesn't use pins. Mounting often uses a thick frame filled with
cotton. Your insect can be softly squished between the front glass of the
frame, and the cotton backing. The previously mentioned techniques are
preferred if the insects are being preserved for scientific study because
they can be easily moved around to be examined from all directions.
However, mounting is a great way to show off your collection that takes up
less time, and can be hung up on the wall. They also make great presents
to your friends and family. Who wouldn't love to get a butterfly or
dragon fly to hang on the wall?
Labeling
It is always a good idea to label your insects. The collection label
should include where the insect was caught, the date it was caught, and
the name of the collector. Other information, such as the time of day,
weather condition, and habitat can also be added to the label. A second
identification label can also be added which gives the name of the insect
and the name of the person that identified it.
Labeling helps scientists remember when and where they obtained the
insects. This allows them, and other scientists, to try to catch more of
the same insect in the future, or to study the movement of insect
populations over time.
Collection boxes
Collection boxes are simple, study boxes with a Styrofoam bottom in which
to place the pinned specimens. Moth balls or other preservatives can be
added to the box to prevent other insects from coming in and eating your
collection. The boxes are usually equipped with lid latches to protect
your specimens when you transport them. Boxes can either be built at
home, or purchased.
Collecting insects is a fun way to learn about the world around you. I
recommend to you the Peterson Field guide for Insects by Donald
Borror and Richard White. This is a great book for identifying insects,
and also has more information on collecting and preserving insects. They
also include some diagrams to help you understand the pinning techniques a
little better.
Bioquip is a company that
specializes in entomology products. You can buy spreading boards,
collecting boxes, vials, pins, and many other things from them, as well as
many other books to help you get started collecting insects.
If you have any more questions about entomology, please feel free to ask
myself, or any other entomologist that you can find. (Entomologists are
not only the smartest scientists around, but they are also the
friendliest!)
Good luck!
John Carlson
MAD Entomologist
Try the links in the MadSci Library for more information on Zoology.