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A Mothing How To.

The study of moths is interesting and rewarding, there is still much to be learned about the moth fauna of Australia and amateurs can make a valuable contribution to the knowledge bank. This page details how I go about attracting and photographing moths in my home area of Central and East Gippsland.  As everyone would be aware, moths are attracted to light at night time, and that is, generally speaking, how to go about the mothing process to coin a phrase. Moths are particularly attracted to a light with a strong ultra violet characteristic, and mercury vapour lamps are ideal for the purpose. The type I use is 250 watts, self ballasted, and held in a simple screw mount fitting. Be aware that ultra violet light damages the eyes and looking directly at the light should be avoided.

The lamp is used to illuminate a white sheet, and there are a variety of ways of suspending the sheet. My solution was to make a three part free standing upright from square section steel tubing, to which the sheet, stapled to three light pine battens is secured by thumb screws and built in bolts. This has the advantage of taking only a few minutes to assemble and has proved to be very effective. The light is fixed at the top of the stand which is positioned on one end of a white groundsheet pegged down with tent pegs. The power source is a small one kilowatt petrol powered generator.

Moths, and other interesting insects generally settle on the white sheet, though some may settle on the groundsheet, or the ground or shrubs around the rig, so it always pays to check the surrounds with a strong torch from time to time. Moths photographed on a natural background can make a particularly attractive image.

Photography.

The photography of moths belongs in the macro category, and the equipment used needs to be macro capable for best results. There is a large array of digital cameras and lenses to choose from nowadays, but I’ll just describe what I use. This is a Nikon D90 SLR with a 100 mm Tokina macro lens which has proved to be extremely sharp even at F22, where the pundits say definition is lost due to diffraction. I have found the F22 setting gives good sharpness with adequate depth of field.

Those same pundits also frown on auto focus for macro work, but with the need for speed, possible movement of the sheet and the moths thereon, it is the only way to go in my opinion, I have never had a problem. Manual focus can be used of course if needs be, eg. the photographing of micro moths where the camera may have trouble auto focusing.

Flash is generally used although specialised LED lights are also available. The on camera flash can be used, but an accessory speedlight is more versatile. Macro ringlights give even shadow free lighting but make the camera more bulky. A low profile flash unit has given me good results. For ultra close up work I made a simple small reflector to bounce the flash downwards. It is held on with just a rubber band.

Aperture priority is a good general setting for the camera, but has the disadvantage of limiting the shutter speed to one sixtieth of a second. This is suitable for stationary subjects, but even with the short flash duration, the wings of a moth flying up the sheet will be blurred. I have found that setting the camera on manual with the shutter set to the highest sync. speed, I get satisfactory exposure and sharpness at the working distance with the aperture set at F22. This can be fine-tuned using the exposure compensation dial on the camera.

I have the camera set to take highest quality jpegs plus raw, then if any exposure is not correct I can rectify it using the raw file. I use the Aftershot Pro program for this purpose. There is an inherent difficulty in obtaining correct exposure of a moth on the white sheet. Even with the camera set to spot or centre weighted metering it will tend to under expose due to the whiteness of the sheet. This can be corrected by setting the flash control to +1. Experimentation and experience will give the best combination of settings. I don’t use the histogram when photographing moths due to time constraints, there is often just no time to do so when the action is busy.

Locations.

The larvae of moths feed on many different things, foliage, the wood of roots and stems, lichens, dry leaf litter, animal scats etc. etc. Foliage feeding moth larvae can be quite specific in their requirements, so to encounter as broad a range of moths as possible, it pays to have mothing sessions in areas of differing vegetation types. Vegetation types also vary with altitude, so that is another factor to consider when picking locations. Moth populations in burnt areas may not have re-established, so if long unburnt areas can be found that is a decided advantage. With present government policy long unburnt areas are becoming increasingly difficult to find.

References.

For Victorian moths the essential reference is the Moths of Victoria series of booklets with accompanying CDs, published by the Entomological Society of Victoria, and researched and produced by Peter Marriott, Marilyn Hewish, and Axel Kallies.

 

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