Thursday, 28 August 2008

Pitfall Trap

...watch your step

Yesterday at dusk, I set up a pitfall trap. No I'm not hunting stray tigers, not even Tasmanian tigers. The use of pitfall traps is a common way surveying for ground dwelling beetles. I've had some success with them in Scotland and for some time now I've been meaning to place a few up the hill in the backyard.

While there are all sorts of interesting designs out their I have simply used the humble baked been tin. It was buried so that the rim is at ground level. It is placed alongside a log, the theory being a beetle will be merrily walking along following the edge of the log and whistling 'The Road to Gundagai' until suddenly it stumbles into the trap.


The Pitfall Trap


Was it a success? Well there was one one beetle in the trap this morning. So, on current averages one could speculate that 5 traps might produce 5 beetles a night or 150 beetles per month :-) Of course you wouldn't want to put the trap out on a rainy night as the beetles will surely drown.

I will definitely set up another couple of traps, maybe just once a week or so. The main thing that may hold me up is the thought of eating more beans.

The beetle from last night belongs to the family Carabidae, known as Ground Beetles. These are the most likely catch in such a trap. The Catalogue of the Insects of Tasmania list 223 Carabids from 20 subfamilies.


Ground Beetle - family Carabidae (10mm)



6 comments:

  1. I must give this a try Mosura, I love baked beans!

    ReplyDelete
  2. Thanks Duncan - Oh well - you can eat the beans and I'll have the tins :-)

    ReplyDelete
  3. Wouldn't they be singing
    "It's bean a hard day's night..."

    ReplyDelete
  4. Thanks Tyto Tony - Yeah well I was going call him Ringo :-)

    ReplyDelete
  5. G'day Mosura,
    Ignore those comments from Duncan and Tony, this is serious stuff. (Although, I am partial to a baked beans on toast breakfast - could send you some tins).
    There is a 'Bug Blitz' program in a few schools around here. The kids learn to trap insects and identify them etc, and they love it. The program is supported by the Gould League and the Hugh Williamson Foundation. A bit of Googling might enlighten you some more if you are interested. I got briefly involved at one stage from a birds and bugs point of view. The kid's enthusiasm and eagerness to learn was infectious. We had a great time.
    Gouldiae.

    ReplyDelete
  6. Thanks Gouldiae- Thanks for the information. I doubt I'd be in a position to get involved but it's great to know such projects are going on.

    ReplyDelete