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The Autokatcher rides again

I stumbled across this photo on a German beetling website about 9 years ago and thought it would be brilliant to give it a go. It’s taken me a while but I’m nearly there. Here’s my brand new custom-built Autokatcher frame, bolted to a roof-bar. Brian and Shirley Nelson (B&S Entomological Services) are going to run up a net bag for me and then the Autokatcher will be ready to hit the road!

Autokatcher frame

As far as I know, only two people have ever used a vehicle-mounted Autokatcher in Britain, though honorary mention must go to B.S. Williams who used a bicycle-mounted version in the 1930s! Alex Williams used an Autokatcher in the lanes of Kent in the early 1970s and found quite a few rare and unexpected species – there is a great photo of it in the Coleopterist’s Handbook. And Richard Lyszkowski told me he’d once spent an evening using an Autokatcher which generated an immense haul of mostly tiny beetles that he has never managed to identify!

There’s a great article about using Autokatchers, including the occasional misadventures, on Andreas Herrmann’s website here.


7 Comments

  1. Clive Washington says:

    I’ve wanted to try this out for a while, maybe this year I can get round to it. I think the biggest problem you will have is that the net will want to be blown flat due to the wind resistance. However it looks as though your car aerial is in an ideal position to act as a support, by running a wire from the aerial to the top of your wire frame loop. Might improve the radio reception too!

  2. markgtelfer says:

    Clive, That is a steel frame so I don’t think the forces will cause a problem. But I won’t know for sure until I’ve got it finished and given it a test run.
    I will post full details online for you and anyone else who is interested in getting their own Autokatcher.

  3. Clive Washington says:

    You can get a rough idea of the drag force by using the side load calculator here:
    http://www.soundcedar.com/calculators/force.wind.php
    A lot will depend on your net mesh (the calculator is for solid walls) but I would not be surprised at a 30lb load if youre doing 50 mph. If you can get hold of a large spring balance you can then see if the frame will take the load.

  4. markgtelfer says:

    Excellent Clive – many thanks for that. My frame is about 4.9 square feet (diameter 103 cm) so if it was filled with an impermeable material there would be a load of 20.4 lbs at 30 mph. I don’t have a spring balance but I could try lifting 20 lbs with it and see what happens.
    I don’t anticipate needing to drive at any more than 30 mph and experience of holding relatively flimsy hand-nets out of the windows and sunroofs of cars at these sorts of speeds suggests that the forces are well within their normal parameters
    … unless you hit something!

  5. I thought of something along these lines for catching moths at night but there was one problem. My obsessive tendencies demand a grid reference for every record so how do I know what was netted where. It’ll be fun seeing the expressions on folk when you drive by!

    Good luck.

  6. Clive Washington says:

    I would suggest that you don’t tell your insurer what you are doing… and be very careful!

  7. markgtelfer says:

    Andrew,
    I will try to find sites where I can drive a short circuit, ideally within a single 1-km square, if not within a single 10-km square.

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