Photographing Aquatic Larvae

One of our members has suggested that I post a description of the techniques I currently use to photograph aquatic insect larvae. I do a lot of tinkering with different techniques, so my methods are always evolving, but here are some notes on where I am to date. (I've uploaded some snapshots of my setup in the "Set-ups for Photography" section of Bugguide.)

To photograph aquatic larvae, I use little mini-aquariums, which I make from 2" x 3" microscope slides, as well as slides measuring 4" x 5".

I glue the slides together using aquarium cement/sealant.

I sometimes use backdrops, which I set up behind the mini-aquarium. I use pieces of felt, which I purchased for 29 cents each at a craft supply store. I rig the felt behind the aquarium using a little wire cooling rack that I bought at a dollar store. I attach the felt to the wire rack with those small binder clips you get at Staples. You can use them in conjunction with neutral density gels to adjust the color of the backdrops. The B&H Photo company sells 20" x 24" neutral density gels on their website for $6.50 each (the product name is Gamproducts Cine neutral density gel). These gels come in different tints. I use the lightest tint; I take one 20" x 24" gel of 0.15 shading and cut it into 4 pieces; I then use pieces singly or in combination to control color ambience.

When I'm ready to shoot the bug, I put a layer of small-sized aquarium gravel in the little aquarium. I have used aquarium sand, but I prefer very small aquarium-gravel pebbles. I'm very particular about the little stones I use for substrate. I've sometimes spent 2 or 3 hours with a pair of forceps selecting individual pebbles out of a dish of aquarium gravel. Because I prefer higher-contrast images, I like to use darker aquarium gravel. I would suggest avoiding white stones or white sand. I use filtered tap water.

Before putting the larva into the aquarium, I first place the bug in a little 3" strainer and spray it by hand water, using a hypodermic syringe. Such syringes may be ordered from biological supply houses, but they're also available in drug stores as part of a kit for cleaning wax from one's ears. Such kits cost about $5.00. This spraying of the larva cleans the bug's setae a bit. This is important because, once the bug is in the mini-aquarium, you'll have to harass it from time to time to get it to move to different orientations so as to get various shots. Also, larvae tend to park themselves in corners or near the edges of the box, and if you don't want to have the edges of your aquarium in your photos, you'll have to get the bug to move. This means you'll need to harass the bug from time to time. Now, some species tolerate such harassment better than others. For example, Eastern Pondhawk larvae are quite docile, and you can move them around without much problem. Most species, however, become somewhat agitated, and some become extremely agitated. Such larvae will scoot around the box very energetically. These bugs will often expel water out of the box. I've even had larvae squirt my camera lens. Now, if such a bug's setae were coated with detritus at the time you put them into the mini-aquarium, all that scooting around would soon result in a lot of particulate plant matter floating in suspension throughout the water in the box. This would cause a lot of visual anomalies in the photograph. Also, cleaning off much of that detritus from the setae gives you a better view of the color and density of those setae. And for some species, hairiness of dorsal spines is a feature useful for identification. So for a clean photo, I recommend spraying the larva with clear water from a syringe before putting them in the box. I just put the bug in a little strainer, give it a good squirt from the syringe, gently tip the bug into the palm of my hand, then drop it into the water-filled mini-aquarium.

After putting the larva into the box, I then photograph it with a tripod-mounted SLR. I shoot it at a 1-to-1 magnification rate, using indirect lighting. For lighting, I just use a conventional camera-mounted flash unit, but I bounce the light off a reflector. I always take a lot of shots from various angles, primarily so that I'll have enough information to later identify the larva using ID keys.

I've been ID'ing these bugs using Barbara Packarsky's "Freshwater Macroinvertebrates of Northeastern North America." I've also used an online ID key that is available from a U. of Mich. website called "Odonata Larvae of Michigan."

The last thing I do, just to make sure I'll have enough info to identify the bug, is to take my camera off the tripod, place the bug in a shallow dish of "spring water" (actually, for a dish, I use a 77-mm UV filter -- I just set the UV filter on a table, pour some "spring water" into it, and put the bug in the water). I then take a small series of dorsal and ventral views, holding the camera in my hand (ie, not using a tripod). Some UV filters I've used have leaked (but not much); but the 77-mm Tiffen UV filter I've been using lately seems to be watertight. By setting the water-filled filter on top of a millimeter ruler, I can get an accurate measurement of the bug; in the resulting photos, the mm ruler is easily apparent beneath the bug, allowing accurate measurement. This also helps in determining the relative lengths of lateral spines, which is often useful for identifying dragonfly larvae.

After photographing the bug, I return it to its natural habit, usually no worse for wear.

Before photographing them, I keep the larvae in small specimen jars containing water from their natural habitat; after photographing them, I put them in a large jar with habitat-water and habitat-plant matter. (I "collect" such material at the time I collect the larvae.) Most of the dragonfly larvae I've been photographing this summer have come from water with very low oxygen content. Such bugs can tolerate life in a jar for quite some time. In fact, on one occasion, an Eastern Pondhawk that I had finished photographing underwent emergence before I could get it back in its sump hole. While I was sitting at my computer, I happened to look up to see a young female Pondhawk sitting on the lampshade of my desk. I found its exuvium hanging onto the electric cord of our TV cable box.

I have found that damselfly larvae become susceptible to an infectious disease of the gills after being kept in a jar of pond water and plant material for a few days. I would think that the capacity of the bug to tolerate life in a jar is related to the degree of aeration of the water of the bug's natural habitat.

Care should be taken when handling damselfly and mayfly larvae, because their gills and tails are easily damaged.

I have found aquatic insect photography to be most interesting; it doesn't require a lot of space (my "portrait studio" occupies a corner of a small room), and larvae are very easy to collect. (Ten minutes at the old sump hole gives me more bugs than I can shoot in a week.)

Examples of some of my aquatic insect pictures may be found on my "My Images" page of BugGuide (http://bugguide.net/bgimage/user/19459).


Best wishes,

Catfish