Before starting an insect collection, one should know how to properly capture, kill, mount, and label the insect. Not only does it give the collector much enjoyment owning an insect collection, but also one may learn a lot from studying the insects in his collection. There are many new species that are discovered by collecting, since it is hard to identify a specimen just by looking at it. There are many techniques used to collect and preserve insects, I will try to fit most of them into this article. If you do not wish to own an insect collection, but still would like to learn about the diverse insect world, taking photographs of live insects may be the better choice for you.
Recommended Collecting Tools and Techniques:
Funnel net (Butterfly net)--The most common and useful tool, which can be easily made or purchased inexpensively at many stores. A diagram of a butterfly net can be seen here.
A sweep net—Similar to a butterfly net except it has a tougher cloth in place of netting. It’s used to sweep through weeds without getting torn.
Aquatic net—Used to collect insects that live in the water.
The aspirator—Used to draw small insects into a small glass or clear plastic bottle. The aspirator is simply a small bottle with two hoses inserted through the stopper in the top. When air is drawn out of the bottle with your mouth through one of the hoses, the insect is drawn in through the other hose into the bottle. A diagram of an aspirator can be seen here.
Pitfall trap—Buried flush with surface of soil and the insect will fall into trap and will not be able to escape. The trap may be used with or without bait. Some baits include fermented fruits, carrion (meat), dung, yeast, fungus, and many household foods such as dog food and cereal. A diagram of a pitfall trap can be seen here.
Light traps—Used at night, most effectively used to attract moths but may attract other insects as well. Some lights commonly used to attract insects are blacklights, mercury-vapor, and ultraviolet. The easiest kind trap to make is simply a sheet strung between two poles or trees with one of the lights listed above reflecting upon it.
Butterflies are captured easily while resting, as they are much harder to catch while in flight. Moths are most commonly collected during night at a light trap. If you do not have a light trap, moths can be attracted to incandescent lights, such as your porch light. Specimens of Diptera
(flies) are mostly obtained with the butterfly net, while in flight or resting. Odanata
(dragonflies and damselflies) are swift and live around the water. These are caught while in flight or resting with a butterfly net. There are many techniques used to collect Coleoptera
(beetles). Pitfall traps are one of the best ways to capture beetles, but they can be obtained by using a sweep net through thick weeds, swishing an aquatic net through a creek or pond, attracted to one of the light traps mentioned above, or just by netting them with a butterfly net. Orthoptera
(grasshoppers, crickets, and katydids) can be collected with a sweep net or butterfly net. Hymenoptera
(ants, bees, wasps, and sawflies) are mostly captured by using a butterfly net. Himiptera
(true bugs, cicadas, and hoppers) are easily caught with a sweep net or butterfly net.
Of course, using almost any collecting method will yield some insects, but the more collecting techniques you try the more diverse collection you will achieve.
The main method of killing insect specimens is the fumigation method. For the fumigation method you use a jar with a tightly fitted lid that has plaster or sawdust in the bottom, which is soaked with a chemical such as, but not limited to, ethyl acetate, acetone (nail polish remover), sodium cyanide*
, or potassium cyanide*
. Insert a piece of cardboard with holes about one inch off the surface of the fumigant (this will keep the liquid fumigant away from your specimens). When an insect is placed in the jar, the fumigant vapors will rise to the top section of the jar and kill the insect. A diagram of a fumigation jar can be seen here.
Alcohol is the best killing agent for smaller hard-bodied insects (ex. Beetles, Coleoptera
). Simply place the insect to be killed in a container of isopropyl (rubbing) or ethyl alcohol. This is the quickest and simplest method of killing but it cannot be used on members of Lepidoptera
, since it will wash away all of their scales.
The last killing method I shall mention is the freezing method. This is my favorite method, since there are no chemicals used. Just put your insects in a bag or jar and freeze them. Keep in mind, if you use a glass jar, condensation will form, possibly harming specimens with scales.
If you want to reposition or change a pin in a specimen you will need to moisturize it. Take a jar and place a few cottonballs in the bottom. Saturate with water or relaxing fluid available at most biological supply companies. Place your specimen in the jar and after about twenty-four hours, it should be movable. I have developed a quicker method that seems to work very well. It can be seen here.
Hard-bodied insects may be relaxed by soaking in alcohol.
Pinning is used for medium to large insects. Entomological pins can be purchased at most biological supply companies. Entomological pins range in size from 000 to 7, with 7 being the largest. Size 2 or 3 are most commonly used. Common pins are made of lacquered, tempered spring steel and are approximately 3.5 cm in length and range in price from about two to five cents each. For about five to seven cents, insect pins are made of stainless steel, which will not rust. Most of the time the pin is inserted in the center of the thorax, but with beetles, the pin is inserted in the middle of the right elytron (wing sheath). A diagram of mounting positions can be seen here.
There are many ways to mount insects, I have shown a few in my diagram. Spreading boards are used for Lepidoptera
and insects with large wings. A diagram of a spreading board can be seen here.
Foam of a thickness of at least 1-inch thick can be used for all other insects. Once positioned the way you desire, let your specimens stand undisturbed for about 3 days to dry. After the specimens are dry, they may be removed from the foam of spreading board and placed in a storage box (see “storing your collection” below).
For insects too small to pin, points are used. Points are simply slender triangles of thick paper to which an insect is glued to the thin end and a pin is inserted through the wide end. Different types of glue may be used, but I mainly use the common white glue. An alternative to mounting small insects on points is the double mount. This can be used for most insects, especially micro Lepidoptera
. A very small Minuten pin should be inserted in the specimen, which is then inserted in a small block of cork. A standard insect pin should then be inserted in the opposite end of the cork block. A diagram showing how to mount small insects can be seen here.
Soft bodied insects and arachnids may be stored in vials filled with alcohol. A label should be inserted in the vial, written with alcohol proof ink (see labeling instructions below for what should be printed on the labels). If you are preserving insect larva, you may need to insert specimens in boiling water. If this is not done before storing in alcohol, specimens may blacken.
Every specimen in your collection should be properly labeled. Specimens lacking proper collection data do not have much scientific value. Labels may be hand-written with alcohol proof ink, such as India ink or printed with a laser printer. Printed labels are much easier to read than hand written labels. I have found that inkjet printers work fine as long as the ink is not alcohol soluble and the printer is able to print small enough. A font size of 3 or 4 should be used for printed labels. Labels should be positioned parallel with the specimens body. The first label to be put on the pin should contain country, state or province, county or parish, nearest town, date of collection, and collector’s name. Dates may be written several ways, such as, 20 VI 1943, VI 20 1943, or 20-JUN-1943. Dates should not be written as 6/20/1943 or 20/6/1943. The second label should contain habitat and method of collection. If the specimen has been identified, a third label should be used containing this information, (species name, sex of the specimen, etc.). In order to position the labels of equal height on all of your specimens, a pinning block is used. A pinning block is simply a block of wood containing three holes. The first step is used to position the insect’s body at the proper height on the pin. The second and third steps are used for positioning the labels. The third label, if used, must be positioned by hand, since there are no pinning blocks with four steps on the market today. A diagram of a pinning block can be seen here.
Storing Your Collection:
Your collection should be stored in wooden storage boxes or cabinets with trays. Boxes and trays are lined with cork or foam. Wooden cigar boxes may also be used in which to store your collection. Your collection must be sealed tightly with a fumigant in order to keep pests from destroying it. A fumigant such as naphthalene (mothballs) or paradichlorobenzene*
will deter most pests, but your collection should be checked monthly for damage. If your collection is not properly cared for, it will be destroyed by pests and all the time and money put into it will be wasted. Here are two photos of a collection someone neglected:
If you lose interest in your collection, donate it to a museum so it can be preserved for others to learn from for many decades.
Entomologist supply houses carry a wide range of items nessecary to the insect collector. The following links are just a few of these.
Austerlitz Insect Pins, Discount Insect Pins
Ward's Natural Science
* All chemicals mentioned in this article should be handled with care. Follow all warning labels on these products. Avoid prolonged exposure and skin contact as much as possible.
NOTE: I have received permission from Troy to post this article on Bugguide.