Methods

Insects are prepared for study and storage in three basic ways: pinning, fluid storage, and mounting on microslides. Adult insects or the immature forms of hard-bodied insects such as those with incomplete metamorphosis are pinned through the thorax of the body, unless too tiny, and then they are mounted on card points (see later). Insect pins, available from supply houses, are long and very sharp. They range from tiny headless "minuten nadeln" for mounting specimens on tiny blocks of foam, which in turn are put on regular insect pins, to pins that are numbered to match the general size of the insect. Size 000 is the smallest made and bends very easily. Most small insects that can be pinned are at least 5 mm in length, with a thorax big enough to hold the pin. Most medium and large insects are pinned on sizes 1 to 3. Sizes 4 to 7 are sometimes available for large specimens.

Preserving Insect Specimens in Fluid

Insects that are too small, or the bodies of which are too brittle or soft, should not be pinned. They should be stored in glass vials in 70% ethyl alcohol (EtOH). Other special fluids, especially those that preserve colors, can be learned from the works under Further Reading. Actually collecting in alcohol can be done using traps of any type (light, malaise, pitfall, and some bait traps). The larger insects can be dried out later and pinned. However, collecting in fluid is NOT recommended for collecting Lepidoptera (butterflies and moths) or Culicidae (mosquitoes) because they have patterns formed of colored scales and those may be ruined by the fluid.

Vials used are often of the "patent lip" type with neoprene stoppers. The author prefers to use 4-dram vials with size 0 stoppers and store them in plastic racks and cardboard boxes with partitions available from supply houses. A better alternative is the screw-cap vial, which should be equipped with "polyseal" plastic sealing inserts. One of the biggest problems with liquid-stored specimens is the drying out of the fluid. I believe the latter storage to be superior because the alcohol does not discolor with years nor does the cap change shape (stoppers swell or stick to the glass).

Many tiny insects such as lice, fleas, and thrips can be stored in EtOH until such time as they can be made into permanent microslide mounts with Euparol, Canada balsam, or some other mounting medium.

Pinning Insect Specimens

1. Be sure the insects to be pinned are soft enough so that they will not crumble when you handle them and attempt to pierce them with the pin. These can be just-caught, or they can be softened, if dry, in a relaxing box (see earlier).

2. Select the pin and pierce the high point of the thorax with the point. Push the pin straight through the thorax. Check straightness by observing from front and side to see if the pin is perfectly perpendicular to both the transverse and the longitudinal axis of the insect.

3. When the insect, such as a grasshopper, has a middorsal ridge in the thorax, pin just to the right of the ridge.

4. For beetles, insert the pin in the right elytron (front wing) close to the midline. Do not pin beetles through the prothorax.

5. Push the pin on through when you are satisfied with the position. One-third to one-fourth of the pin should be showing above the insect's thorax.

6. If the abdomen or legs are drooping, push the pinned insect into a block of foam plastic or a cardboard box to support these parts until they are dry. Then remove the insect and label it.

7. Most museum specimens do not have legs and antennae adjusted to a life-like position when they are pinned. However, for display purposes or personal satisfaction one may move these body parts into desired positions on the foam or cardboard support and fix them temporarily with pins over or against them.

Placing Insects on Card Points

A card point is a small wedge of high quality (100% cotton content) cardstock, punched from the sheet with a special punch obtainable from a supply house. There are several different shapes, but the author prefers the ones with the wide end rounded.

Card pointing is used for tiny insects that are hardbodied enough not to lose shape when dried. Size usually ranges from 1 to 5 mm or slightly larger in length. The author normally selects from large samples of dried specimens collected in sweep samples or light traps.

1. Punch out a number of card points. Place them on top of a firm foam plastic or cardboard surface.

2. Push the point of an insect pin into the wide end a short way from the very end, and push the card point up the pin by inserting the pin with the card point into the top hole of a 3-step pinning block (wooden block with three fine holes of different depths to provide uniform heights of labels on pins) and pushing the point up until it stops. It should be about 1/3 the distance from the top of the pin.

3. Use forceps to turn the very tip of the card point downward at a right angle to form a vertical surface.

4. Put a tiny dab of glue on the vertical surface you have made with the forceps. When doing a number of specimens, put a small drop of glue on a piece of card or paper to use (although it will tend to harden on the surface after a minute or two).

5. Position the insect so that the right side of the thorax is accessible, and touch the glue-covered surface of the card point to the right side of the thorax. (The insect should appear to be "holding onto the card point with its right hand"). Use forceps to position the insect firmly against the glued surface and have it positioned so that its orientation to the ground is as it would be in life.

6. Fill out your insect label with locality, date, and collector's name. Trim it to be as small as possible (avoid large, oversized "barn door" labels). Labels should be printed on 100% cotton light card stock in permanent black (India) ink or can be done on a postscript laser printer.

7. Position the label on the pin and push it up the pin at the middle hole of the 3-step pinning block. As you read the label, the card point and insect should be projecting to the left of the pin shaft. Make sure both card point and label are not tilted or crooked.

8. Place the specimen in a temporary holding unit tray until it can be identified and put in the collection. Identification labels should be affixed below the collecting data label and in a position so that both labels can be read from the same angle. The lowest step on the 3-step pinning block is normally used for the identification label.

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