buried pipe trap
Greenbrier County, West Virginia, USA
May 24, 2017
This design is based on that of Jim LaBonte, but smaller. The pipe is PVC, with slots created using a drop saw. (sawing PVC creates a lot of dangerous plastic dust and slivers, so use proper safety gear if you try this at your house)
The small diameter of the pipe makes them easier to install in rocky forested areas, using a soil auger with a slightly larger diameter. First I dig a small hole about the width of my hand and 4-5inches deep, then use the auger to make the hole for the trap. Then the trap goes in (with a cardboard or plastic sleeve inserted to keep out soil), and loose soil is filled in around the pipe. Then the sleeve is removed, a plastic lid placed on top and the whole thing is buried. Fishing line attached to the lid with a bit of flagging on the end helps with locating the traps later.
The jar is a spice jar, held on with duct tape. A couple of the jars came off when pulling the pipes up, but the tape held up well in most cases. It would be better to modify the screw-on jar lids to be used as a connector, but I haven't gotten around to trying that.
Despite the small diameter, I found these to be very effective at collecting interesting blind soil beetles (my main target) as well as Phorids, Symphylans, Japygids, springtails, wasps, centipedes, ants, mites, larvae.. I left them from May to September, with undiluted Propylene-Glycol-based antifreeze as the preservative, and most of the samples were in great shape.
One site I set these had thick wet orange-red clay soil, which seemed unpromising for soil-dwelling beetles. But it turned out to be just as productive as the other site I tried that had darker looser soil, so it seems worth trying these traps in various soil types and settings.