Blacklighting for insects along the prairie’s edge

At the last new moon I tagged along with some of the University of Illinois’ intrepid entomology graduate students on a collecting trip. On arriving at a patch of prairie outside of town, the students hung a mercury vapor lamp in front of a sheet, powered up a generator, and waited for the catch to fly in. The set-up attracts insects like a porch light, only more so.

Below are some photos from the evening.

Two methods to collect insects: directly into a jar (left), or with an aspirator.

A lovely heptageniid mayfly.
Rove beetle!
The palps on this stonefly make it look like a squid.
A stout scarab clings to the sheet.
Fireflies were thick in the prairie across from the blacklight. A long 30-second exposure captured many flying about (click to enlarge. Seriously- this photo looks much better full screen!)

6 thoughts on “Blacklighting for insects along the prairie’s edge”

  1. I have a few questions about how best to do blacklighting:

    – Is the spectrum of the light important, or will any light work as long as it is intense enough?

    – About how far will an insect fly to reach a light? Is it better to be facing an open field for a long line-of-sight, or facing a stand of bushes or trees that will probably have more things roosting in them?

    – What time of night does one normally draw the most insects?

    1. It’s been a while but here is a link and what I remember:

      -white to blue wavelengths work much better than yellows and reds; coleman lanterns work fine if you don’t have electricity.
      -some insects will come in to the most intense light while others will only come to the edges of illumination; you want as big a target area as possible with a range of illumination intensity. we used to go 3 sheets wide with the light source only in center, but there were a lot of us collecting.
      -insect species vary in the timing, season, and how far they fly as you would expect
      -you want the largest circumference for the line-of-sight as you can get, and as dark a night as you can get, but each spot is different and nearby habitat composition matters, eg a stream or pond, woodland, etc.
      -different species fly at different times, eg dusk vs late night with dusk very important for some species.
      -you get some very wierd stuff coming in that will totally surprise you, almost guaranteed.

      Great fun, bring friends.

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