DIY Entomology Equipment

The following is a guest post by Tucker Lancaster of the Blue Egg Blog.

Flipping through the glossy pages of a Bioquip catalogue, you would think that entomology is a rather expensive pursuit. But, it doesn’t have to be. As an amateur entomologist, I’ve never had money to blow on equipment. Therefore, the majority of my collecting arsenal is home made from commonly available materials. I thought that I would share some of my creations here in the hope that will help others plunge into this exciting hobby without breaking the bank.

Let’s start with collecting equipment. When gathering small insects, such as ants, it is all to easy to accidentally squish your prize. That’s where an aspirator comes in. Though this is not a particularly expensive tool to buy, it is possible to make your own.

As you can see, the mechanism is quite simple. Two pieces of clear vinyl tubing are stuck through holes in the lid of a small jar or vial, and one is covered with a thin piece of cotton to prevent you from inhaling the insects you’re collecting. I used a small piece of cotton from a makeup remover pad, but something thinner would be easier to suck through. For example, fine wire screen or a square from an old pair of tights might work better. Just make sure the holes are small enough! To use it, you point the smaller tube at an insect and suck hard on the other. This pulls your query through the tube and into the vial, where they can be easily collected. This design was inspired the aspirator sold by Bioquip, and operates on the same principles.

Next up is one of my favorites, the Berlese Funnel. It is a device that uses heat to drive arthropods out of soil or leaf litter. These things are usually quite expensive, but I designed and built one for around $25. For complete instructions, you can visit instructables.com, where I’ve written a complete tutorial. To use it, litter is placed onto the screen in the tractor funnel and the light turned on. Any insects that are present attempt to escape the heat of the lightbulb, only to fall through the screen and into a jar waiting below. My design is based loosely on this image from the USDA.

In the summer, when you turn a light on outside is is sure to draw an assortment of nocturnal insects. We can take advantage of this positive phototaxis using a device called a light sheet. To make this one, You need a portable light fixture, a light that fits in that fixture (I use a CFL black light which I found at Home Depot, because black lights attract more insects), a length of rope, clothespins, an old white sheet, and, if you aren’t close to an electrical outlet, a battery and inverter to power the light. First, tie the rope between two trees or posts or trees at a height of about six feet. Then, use the clothespins to suspend the sheet from the rope, making sure that it touches the ground with some slack. Finally, hook up your light and point it at the sheet so that is is illuminated. Night flying insects, such as moths and beetles, will be attracted to the light and land on the sheet. Some will hit it and slide down, which is why you need some slack at the bottom to catch them before they disappear into the grass. I first read about this method here.

So, you’ve managed to collect your insects. Now what? Well, many make excellent short or long term pets, which gives you the opportunity to closely observe their behavior and life cycle. Most can be kept in simple setups, such as jars or terrariums. For many common insects, there are resources on the web detailing their care and feeding. Or, if you’re a little more adventurous, you can try to rear a more obscure insect using available information on its habitat and diet. One useful device for raising beetles and other insects with soil or wood dwelling larvae is a cardboard rearing box. It consists of, as its name suggests, a cardboard box with a tight fitting lid and a clear jar extending from a hole in its side. Material containing the larvae is place in the box and the box closed. When the adults emerge, they will likely be attracted to the light entering through the jar and accumulate there. However, not all adults will be attracted to light, so it is important to periodically check their progress.

Currently, I am using this box to raise Fire Colored Beetles from larvae I collected late November in Indiana. Since they have a tendency to cannibalize each other, I have placed each larva in its own ziplock bag full of rotting bark. This also keeps the medium moist, as it would be in the wild. Once they near adulthood, I will open the bags so that the beetles can reach the jar as intended.

If you want to permanently preserve the insects you find, then you will probably end up starting a pinned collection. However, before you can pin an insect it has to be dead. This is easier said than done, as many insects are quite delicate and liable to damage themselves if not dispatched correctly. One of the simplest ways to do this is by using a killing jar. To make one, first pour about an inch of plaster of paris into a jar with a tight lid and let is thoroughly dry. Then, add just enough rubbing alcohol or nail polish remover to dampen the plaster. Finally, stick a loosely wadded paper towel into the jar. This will soak up excess fluid and give the insects a place to hide. An insect place in the jar will quickly suffocate without inflicting serious damage upon itself. It can then be removed and pinned for your collection.

Moths and butterflies will need to be spread before they dry in order to display their wings. A simple spreading board, pictured below, can be made from pieces styrofoam. The top pieces with the groove between them are held down with pins so that they can be adjusted based upon the size of the insect to be pinned.

If you don’t immediately spread an insect, it will become too brittle to work with. In order to reverse this, the specimen must be relaxed by placing it in a very humid environment. This can be achieved using an airtight box with a few inched of moist, milled peat moss in it. On top of the bed of peat is a sheet of styrofoam on which the insect is placed. A specimen left in the box will absorb the moisture from the air and become pliable. However, depending on the size of the insect, this can take one to several days. Try not to leave it in the box too long though, as mold is liable to develop.

Last but certainly not least is a place to keep your collection. The best option is a professional Schmitt Box, but if that is out of your price range there are a number of suitable DIY alternatives. However, please note that the latter will not protect you collection nearly as well as the former. The simplest would be a shallow box with a tight lid and a layer of styrofoam glued to the bottom. However, what’s the fun in keeping your collection hidden away in a drawer? So, last year I built a pair of glass fronted boxes to house my collection. I will not go into detail here about the construction, but if you want to build one try searching for shadow box plans.

If you do decide to keep your collection in a home made box, it is a good idea to periodically freeze your collection to keep any possible pests under control. Mothballs are also an effective deterrent, but tend to disappear quickly if you box is not entirely air tight.

The back of the box consist of a sheet of hardboard with insulation foam glued to it. Over the foam is a piece of poster board cut to fit the box.

As I have demonstrated here, most of the equipment needed to collect insects can be constructed using a few commonly available items and a whole lot of creativity. Below I’ve included a few links that feature other devices that I hope to construct in the future. If you liked this post, visit my blog at www.blueegg.wordpress.com.

Links:

  • Collecting and Preserving Insects and Mites: This is a great resource that includes plans for a number of devices as well as general insect collecting information
  • Manitoba Trap: This site provides instructions for building a Manitoba Trap, which is used to collect horseflies
  • Aquatic Trap: I haven’t tried this trap, but is extremely simple to build and appears to have worked quite well for the author

20 thoughts on “DIY Entomology Equipment”

  1. Excellent post!

    I have a question though. I usually put adults in a normal food freezer for 12-24hours (but the ones who over-winter as adults are problematic). I thaw and pin them right after (they are still pretty pliable at this point); then i put them back into the freezer for a few months to dry. Is this method good for keeping a collection, or will this cause damage to my specimens?

    Thanks

  2. I have a question: how do you ensure enough oxygen/air for this:

    “I have placed each larva in its own ziplock bag full of rotting bark. This also keeps the medium moist, as it would be in the wild. Once they near adulthood, I will open the bags so that the beetles can reach the jar as intended.”

    I also had a momentary shudder at the thought of all those bugs dying for “collections”.

    1. Anonymous Coward

      I dont know the specifics of his plastic bag method but I often use containers with no air holes as cages. Insects(and invertebrates in general) use very little oxygen to go about their business, a daily (or less) opening of the bag provides plenty of air exchange for such creatures.

      On the point of your momentary shudder…I cant imagine why. I feel a distinct discomfort any time a bug smashes on my windshield of my car, something which kills far more bugs than I could ever hope to place in my collection. Every single car does, please stop being dramatic when it is unwarranted.

        1. Anonymous Coward

          Based upon your initial comment I will make the assumption that you do not collect insects, I hope that is not an unreasonable one. I did not, however, assume that you drive if that was your point in your attempt to undermine my point.

          Im going to speculate here and say that cars, in general, are probably the second leading cause of mass insect death in the USA and many other places… I would guess that agricultural pesticides are a likely candidate for first. When you talk of something which a large amount of people find great joy in, that has a miniscule effect on populations of insects in general (so barring cases of over-collection and sensitive species), and contributes a relatively insignificant number of insect deaths in comparison to other causes…all while potentially preserving said insect for hundreds of years after its death if it is given the proper care…and you do so with a “shudder at the thought”…

          There is no way in which you are not being dramatic.

    2. I like the idea of a ‘ethics of collecting’ blog post. This is a question I run across all the time. I coordinate an entomology outreach program at a university; we work with thousands of children and adults each year to introduce them to insects. Often, young students are distressed about the killing of butterflies – “How can you kill that beautiful butterfly?” Some of the answers that have come up in the subsequent discussion: 1. Do you kill mosquitoes? Butterflies don’t feel differently about dying. The mosquito you swatted was only trying to get a blood meal so she could lay her eggs. 2. We spend most of our human lives as adults, but many insects have already lived most of their life span by the time they are adults. 2. To learn about insects we need to collect some (in addition to observing natural behavior, which we think is more fun than killing insects). Many fly too quickly for us to learn much about them, some are miniscule; others are hidden from us because they are nocturnal, live under bark, in the water, etc. We don’t kill them just for the fun of it. Collected insects provide us with valuable information we could not obtain any other way 3. Collected insects help us learn field identification. I study flower visitors; by collecting a new species whose behavior I have closely observed, I can identify it the next time I see it in the field. 4. We can share our insect collections with people and help them appreciate insects. One last point (somewhat unrelated, but why not vent here): Why is it OK to drive through a national park, killing countless insects, or sit by the campfire swatting mosquitoes, but if I catch one and put it in a jar, I can be fined?

  3. Good post. It’s one area I have not gone into myself in any major way, but I know if I really want to understand bugs in greater depth I am going to have to start a collection. I would like to see a post on what makes a collection ‘legitimate’ to entomologists i.e in regards to correct labeling and record keeping.

    1. Collector, location, date are essential. Habitat information is always helpful, and is placed on a second label (a collecting journal is helpful). Small labels are better! Correct identifications (give the person’s name who provided the ID if it isn’t the collector). A large collection will be easier to access with a good database (in that case, number each specimen in the collection)

  4. Nice overview. Another simple tool is a white pan for quick sorting of leaf litter/soil samples. Then, of course, there is the stick, crossed slats, and canvas beating tray.

    One point about Berlese funnels, though. For most of the soil arthropods, it seems to be the humidity gradient established by the light bulb as it dries out the sample that is most important, not the light per se. The first day or two a sample is on, not much comes out but the highly active animals that fall in. Once the critical humidity is reached, though, it starts raining arthropods.

    Since your Government, in its infinite wisdom, is making incandescent light bulbs illegal, you may soon need to find another source of heat/ drying. The original Berlese funnel was a bunsen burner under a pot with a series of copper tubes that conducted the hot water over the sample, much like a radiator. That seems pretty complicated, but the sun will work and even dry air in a warm room – although it is pretty slow.

    1. Anonymous Coward

      A more simple arrangement that might be possible is to utilize a CHE(ceramic heat emitter) designed for the keeping of reptiles and such.

      I was under the impression that the light/heat was sort of a dual effect though, the light driving things down while also drying out the media.

      1. CHE is an interesting idea. With a reflector you might even get more or less directional heat. Soil biologists may have to go to something like that once the incandescent bulbs are gone. Having a standard source of heat (e.g. 25 or 40 watt bulb) is important for quantitative research – you want to try and treat all your replicate samples the same. One problem with light bulbs is that they tend to attract insects up and out of the sample (not into the funnel) and from outside the sample.

        The studies I have seen have demonstrated a strong effect only for humidity, not for light. Soil is a good insulator and light isn’t going to penetrate very deeply. Also, many soil animals lack eyes and seem to ignore light – good for when you want to photograph them.

    2. In Paraguay, I would just set Berlese funnels out in the tropical sun for an afternoon. Got several new country records of ants that way. No need for any kind of lightbulb at all!

      1. Yeah, I’ve done that for surveys, but a rainy week can be frustrating. I know one scientist in Canberra that sets his funnels in a glasshouse with no other heat source.

  5. Nice post! One thing I would specify for the aspirator is that the tubing that goes into your mouth be of food grade quality. The second caution is one about allergies, although this is a post about DIY building vs. buying collection equipment.

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