Methods | Collecting Methods for Staphylinidae and other Staphylinoidea | Indirect Collection Methods: Blacklight Trap

Many night-flying insects orient toward a light source and hence can be attracted to a trap using light as the attractant. In general, blacklighting utilizes ultraviolet light (usually mixed with white light) to attract beetles that fly from dusk till dawn. This light source has proven more effective for collecting beetles, and especially staphylinids, than other kinds of light (white or mercury vapor) used routinely for collecting Lepidoptera. A detailed description of the blacklight we use, the materials, and operation can be downloaded here. The very portable blacklight trap we use has four vertical transparent plastic panes radiating out from a 15-watt blacklight (BL) tube, with a collapsible collecting basin suspended below it. Insects fly toward the light, hit the transparent barrier and fall into collecting fluid in the bottom of the trap. Operating a blacklight trap requires a battery, portable generator, or car battery for a power source. We rig our blacklight up to a 12-volt car battery and usually begin collecting around dusk and continue on into the evening depending on success.

Blacklighting can be extremely productive for staphylinids under the right conditions. Aside from season and location (water-edge taxa seem to be most attracted to light), ideal flight conditions for staphylinids seem to be: warm temperature (preferably at least 21°C/70°F), high humidity (recent rain is good), little or no wind, and the time of transition from dusk into darkness. Avoiding full moonlight may be helpful. We don’t often encounter all these conditions, and therefore don’t do a lot of blacklighting.

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