Nocturnal forays, part 2: on Demon traps

Elsewhere, Mellanby describes more closely these Demon cockroach traps, which he also used to trap cockroaches in the rat room to study their periodic activity:

These traps are circular, 22 cms in diameter at the base, with sides sloping gradually towards the center where there is a circular opening 11 cms in diameter and 4.5 cms above the base. The sides are roughened on the outside to give a grip to insects’ feet. The hole at the top is partly covered over with metal vanes which tip over when a cockroach stands on them, and so the insect falls inside the trap. There is a small container for “bait” (a mixture of beer and banana is advised) in the middle, and the insects are supposed to fall into the trap as they try to reach the bait. Once in the trap they cannot climb out. Actually an unbaited trap was found to catch as many cockroaches as a baited, and no bait was used. The traps are not intended for catching bed-bugs, but they do catch them, and any other insects which are running about; beetles, spiders and woodlice have been also captured.

Mellanby, Kenneth. 1940. Rhythmic Activity in Domestic Insects. Acta Medica Scandinavica 103: 89-98. doi:10.1111/j.0954-6820.1940.tb11083.x

This really is impossible, isn’t it? How can such a trap work for bed bugs? What do you think?

Can bed bugs crawl on a concave surface? Let’s say that they can’t (I don’t know, do you?) — why would they drop into the trap in the first place?

I don’t want to get ahead of myself too much but here are some possibilities that occur to me (if you find them wanting, consider the source!):

  • Perhaps in a heavy infestation practically anything will catch bed bugs — as long as they can climb it — and will trap them as long as they cannot crawl out
  • Perhaps the traps, while not baited for either pest, did in fact attract bed bugs. How could they possibly? By preserving in them the smell of their buddies, their conspecifics?

By now surely you’ve taken a peek at the photo below and my surprise is no more. Let me tell you briefly how difficult it was to find the Demon cockroach trap that Mellanby used in his natural infestation in the rat room, the Demon cockroach trap used in Britain for many decades it seems, a trap that must have been so common, he felt no need to describe it until he presented his paper in another country. Extremely difficult.

Because it wasn’t called a Demon cockroach trap! Mellanby probably couldn’t bring himself to call it by its common name. Maybe because it’s totally wrong and silly.

It was called a Demon beetle trap.

My aim is to not acquire any more pest “interests” in this lifetime but even I know that is just wrong. Designed to mess with us seventy years later?

Beetle as a gentler, inoffensive word for cockroach, I just didn’t know. I would still be a bit unsure that this is in fact a case of euphemism, as opposed to say, a case of a product used for several pests, but there is Mellanby being super clear as always. (And I have since learned that if I listened to Kanye West I would have figured this out much sooner.)

So here is your Demon beetle trap:

Demon beetle (cockroach) trap

Demon cockroach trap

In a nice historical rhyme, the eBay seller of this trap happens to be in a certain town in South Yorkshire.

And here is a really fabulous advertisement page from a G. Harding & Sons catalogue, dated March 6, 1901. The most successful Trap yet introduced.

The third installment of this series is a bit more involved, but I am hoping it will automagically appear on this page sometime this weekend. Until then, very best wishes for the new year. I wish that you will be hopeful about the future, about our bed bug (to use a gentler word) situation.

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