Some questions on the behavior and preservation of insects..

[cshahar]

I have some questions regarding insects and photographing them.

Firstly, do dead insects need to be preserved say in a refrigerator? I know they have exoskeletons, but do their soft parts start to decay? If they have to be preserved, how long do I have before they start to decompose? For instance, I can go into town and gather up a whole lot of dead insects near a street lamp. Are they appropriate for extreme macros? Does their color change after they die? If I have to refrigerate them, is it enough to simply stick them in a little pill box, or will there be moisture problems as a result?

If i wanted to freeze a live insect for a couple of hours just to immobilize them, do I risk killing them? Will this really work, or will they thaw out quickly?

There is a local insect museum here. Do you think it is a good idea for me to take my gear there and photograph their samples?

Let us say I have a studio set up (horizontal gear), is there a procedure to follow to pose the insects, or is it simply a question of nudging them into position?

I am not yet interested in going out into the field. Getting insects to sit still long enough seems daunting, although a particularly chilly morning might make them a bit sluggish. I would imagine the backgrounds too would be more interesting.

Anyway, that's it. I hope my questions aren't too naive, but this is the beginners part of the forum!

Thanks!

-Charles

[rjlittlefield]

Charles,

Firstly, do dead insects need to be preserved say in a refrigerator? I know they have exoskeletons, but do their soft parts start to decay? If they have to be preserved, how long do I have before they start to decompose? For instance, I can go into town and gather up a whole lot of dead insects near a street lamp. Are they appropriate for extreme macros? Does their color change after they die? If I have to refrigerate them, is it enough to simply stick them in a little pill box, or will there be moisture problems as a result?

Unfortunately the answer to all these questions is "It depends!"

Yes, soft parts will decay if kept warm and moist. But most insect bodies will dry before decaying if they are kept in dry air at or above room temperature.

With hard-bodied insects like most beetles, drying leaves most of the exterior features unchanged. Drying is the most often used method of preservation in such cases.

With soft parts, drying will deform and change the surface texture significantly, sometimes dramatically. Eyes are particularly vulnerable. The eyes of critters like mayflies, lacewings, and mosquitoes will rapidly change from shiny and highly reflective, almost glowing, to dull black and shriveled. The same problem occurs more slowly and to a lesser extent in many other groups including larger flies and butterflies. Even beetles can develop cracks in subsurface layers that produce striking patterns in dried specimens that are completely absent in live or fresh.

Refrigeration works well for periods of a few days. At some point mold will kick in if the specimens stay moist.

Freezing is a good longer term solution for dead specimens.

Chilling subjects will often make them quiet, but because they are small, they warm up quickly. You'll want to have your photo setup all prepared, and even then, they're liable to become active again before you've shot enough images.

If i wanted to freeze a live insect for a couple of hours just to immobilize them, do I risk killing them? Will this really work, or will they thaw out quickly?

Freezing most insects for any period of time will kill them. There are exceptions -- some life stages of some species can be frozen stiff as an ice cube and still recover. But that's not the way to bet, and in fact freezing is probably the most common method to get freshly killed specimens in good condition to photograph.

There is a local insect museum here. Do you think it is a good idea for me to take my gear there and photograph their samples?

It can't hurt to ask. They may very well have some specimens they would let you work with. You should develop technique in your own work areas first, so that you understand at least the most important issues. (Dry specimens are quite fragile, for example. It is astonishingly easy to damage them.) Then at the museum, describe to the curators what you would like to do and how you propose to do it, and see if they can identify any other issues or alternatives.

Let us say I have a studio set up (horizontal gear), is there a procedure to follow to pose the insects, or is it simply a question of nudging them into position?

There are no fixed procedures, and some would say there are no good procedures. Dry insects cannot be posed except to adjust their overall position, and non-dry insects generally will not stay where you put them. One standard approach is to "relax" dried specimens with high humidity or even direct application of water to joints, then hold the specimens in position with pins until they dry enough to hold position. But except for hard-bodied critters with distinct joints (e.g. beetles), producing a specific pose is an exercise in frustration. Even in the best cases, it helps to be familiar with the critter in life to avoid unrealistic poses. Think of the task as micro-taxidermy.

I hope this helps. It's a hard problem.

--Rik

[cshahar]

Rik, thank you very much. Your answers are most helpful! You outline some very real challenges which I should be aware of in this process.

-Charles

[cshahar]

Rik, I just have a couple of more questions:

1. If I have a vertical setup the camera will be above the insect, and hence my image will show the top of the subject. But the best shots seem to be face on. How do people with vertical rigs take face-on images?

2. I have seen people use Nikon copy stands for vertical rigs. What is usually used for a horizontal setup?

Thanks,

-Charles

[ChrisR]

Insects are usually mounted on pins, so the orientation doesn't matter much. A dead fly, say, won't stand nicely on its legs, and it won't stay still long either unless you're dead as well, pretty much.

Since you mention Nikon copy stands and I have one, I'll point out that they're not especially good. Any converted enlarger or similar would be OK. All it really does is hold the camera still, without tripod legs to get in your way. That's enough for single shots but you'll soon want to "stack" exposures for more depth of field. The Nikon stand has a rack and pinion adjustment which you can use for around half millimeter steps. That, coupled with the general springiness means it's only good for perhaps life size on sensor. For larger mags, many of the rigs you'll see use a microscope base for vertical movement of the specimen up towards the camera.
For horizontal, you can of course tip the stand on its side, but most folk use something like a "Proxxon" milling table or a "linear stage". The tricky part is finding a way to support the camera rigidly at a convenient level, while allowing the movements you're going to need. Solutions usually involve aluminium, nuts and bolts, and a hacksaw!
See the sticky posts inthe Equipment section, and try searching the forum with the the terms in quotes.

[Harold Gough]

Charles,

In some ways the easiest way into working with at least the lower magnifications is to use flash. This freezes motion* (the insect's and the camera's) enabling you to capture the image, if the subject will allow approach for a second or two. Setting the camera and lens (field of view size and aperture) before approaching minimises disturbing movements of your hands just prior to exposure. Using a lens with a long working distance, you can then use live material, avoiding the problems of preservation.

* Subject to the flash being powerful enough for ambient light to not register and of short duration.

Harold