Semper Fidelis - Semper Discentes

An Improved Carrion Beetle Trap

In Coleoptera on June 5, 2013 at 12:29 pm

During the crazy weather of the Winter of 2012-13 here in the Ozarks, I began casting about for some entomological project to keep me occupied, hoping perhaps I could latch on to some small, focused area in which to concentrate my studies in the few years I have remaining.

Discovering beetles crawling all over a well-rotted, roadside deer carcass, I became fascinated with carrion beetles—nifty bugs who “undertake” to devour and recycle dead animals.  I did further reading on the use of insects to determine the time of death in humans, and you’d be surprised at the body of research that’s been done on this subject alone.

As I THOUGHT the weather was moderating in March, I read Bedick, Ratcliffe, & Higley’s 2004 paper which covered sampling methods for the endangered “American Burying Beetle” (Bedick, Ratcliffe, & Higley, 2004) , and modified their suggested trap design slightly.  I put together a half-dozen traps, constructed of PVC, and placed them around my twenty-acre “holler”.  You can see the original trap design on this blog in “I Carry On With Carrion”.

Well, the trap worked pretty well.  It basically consists of one piece of 4” PVC, 18” long, which is buried vertically in the ground, with about 3” exposed.  (The exposed part protects against water running along the ground into the trap.)  At the bottom of the pipe is placed a 6” piece of smaller diameter PVC, into which the bait (well-rotted carrion) is placed.  A mesh screen goes over the top of the smaller pipe, to keep the beetles from actually coming into contact with the bait, and to keep flies from laying eggs on the bait.  Fly larva (maggots), according to what I’ve read, will keep beetles from colonizing the bait.

As I said, the trap worked pretty well.  HOWEVER….

The beetles and flies were somewhat smarter than this amateur entomologist.  They managed to work their way around the screening, despite several innovations I came up with, none of which bear repeating.  This meant I was GETTING beetles, but they were down deep, rummaging around in the VERY-well rotted bait.  To get to them, I had to pull out the smaller pipe, then reach down with my HANDS, and pull out the stinking mess and poke through it to collect the beetles.

Washing my hands six times after each operation still left my hands smelling like corpses.  I needed a better solution.

Here, then, is my NEW design, yet to be tested in the field, which I hope will continue to drag in new silphids (carrion beetles), while keeping my hands clean, unsullied, and sweetsmelling.

Here’s how to build the Sims Model 2 Handsfree Carrion Beetle Trap.  For each trap, you’ll need:

  • 16” length of 3” (inside diameter) PVC pipe.  I went down to the lumberyard and bought an eight-foot section, which will provide SIX 16” lengths.  $12.16 + tax.
  • One half-pint canning jar.  You want the ones that are pretty much completely cylindrical in shape.  They might be called “wide-mouth” jars.  Maybe not.  I had a few lying around the house.  You also need the rings and lids.  Old lids will do.  They don’t have to be completely airtight.
  • One 4-5” square of window screening.  My lumberyard had a bunch of ends and pieces they GAVE me.
  • One piece of string, about 24” long.  I used some nifty florescent green string that I had lying around, just ‘cause it looks cool, and is easy to see.

Here’s the stuff:

Here's the stuff!

      Tie one end of the string to the jar ring.  Center the piece of window screening over the mouth of the jar, and screw on the ring.  That’ll form the screen into the shape shown in the picture.

      THAT’S IT!!!

On my way into town today, I found a freshly-killed squirrel in the road.  This trap has another great advantage in that it lets you handle the bait while it is still fresh, or still frozen, and BEFORE it gets disgustingly stinky.

A squirrel will provide bait for four traps.

A squirrel will provide bait for four traps.

I divided the carcass into four more-or-less equal portions, using a pretty dull hatchet.  Didn’t think it necessary to photograph this part of the process.  I found that ¼ squirrel just about fills a half-pint canning jar.  Filled each of four jars.

Then, I placed the formed window screening on the top of each jar, AND TOPPED IT WITH THE CANNING LID.  I’d already tied the string to the canning ring, and then screwed the ring LOOSELY over the screen/lid, and set the four jars aside, in my woodshed, so that the fresh bait can ripen for three or four days.  The lid keeps the decaying meat from attracting nuisances, and the lid is LOOSE, so that escaping decomposition gases can escape.

DSCF3489DSCF3487DSCF3491

One-fourth of a squirrel, in jars, for ripening.

            After the bait has ripened to my satisfaction, I’ll bury the PVC, as explained above, then take the bait jar, REMOVE THE LID, but retain the screen, replace the ring, and drop the bait jar down into the PVC.     As you can see, the string hangs out the top, so that I can pull up the jar, hopefully with the screen covered with beetles, without having to handle the bait.

DSCF3483   DSCF3486

The jar fits pretty closely into the pipe.                      View from above.

I’ll keep you posted on how well this turns out.

REFERENCES:

Bedick, J. C., Ratcliffe, B. C., & Higley, L. G. (2004). A New Sampling Protocol for the Endangered American Burying Beetle, Nicrophorus americanus Olivier (Coleoptera: Silphidae). The Coleopterists Bulletin , 58 (1), 57-70.

Sims, G. G. (2013).  I Carry On With Carrion.  https://bugsofpopoagie.wordpress.com/2013/03/19/i-carry-on-with-carrion/

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  1. love your blog!

  2. Your article was a trip down memory lane (they say smell is the sense most linked to memory). The first time I saw Silphids collected (on purpose) it was the beautiful Dr. Kelly V. Tindall collecting out of a PVC irrigation riser using MY butterfly net. My net smelled awful for about a week.
    Have you thought about the phoretic mites (e.g. Pelzneria) that are using your Silphids? I am curious…

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