For the last few years I have spent the majority of my spare time on a quest. A quest to find and identify our UK beetle fauna. It started by accident, but after the introduction of Notiophilus sp. at a HIP field meeting I was hooked. I’ve lost count of the logs I’ve turned and piles of dung I’ve dug through (much to the distaste of my girlfriend) fuelled by the desire to find something new and exciting, but my enthusiasm has never seemed to wane.
About 2 years in to my beetle foray I came to an issue, quite simply, I wasn’t finding much in the way of ‘new and exciting’.
I had two options: Look somewhere else (my beetle wrangling had largely taken place in the magnificent county of Hertfordshire) or change my methods. Until now I had largely been flailing my sweep nets in fields and beating any available log with a blind fury in order for it to submit any beetles it may have hidden within.
AND THEN I LOOKED AT TRAPPING…
I had already began to experiment with the entomologist standard ‘the pitfall trap’. However, I had become weary with spending hours looking for them the week after, only to find an inquisitive animal, or ecowarrior had dug up or removed them. Once I even found a makeshift shelter constructed by children (I assume) on top of one!
After lots of research, including this post by Simon Leather I decided to look more closely at ‘Flight intercept traps’ essentially these are a form of barrier put into a flight path of insects that they bump into, landing in a collection reservoir to be collected and identified at a later date.
These range from the costly malaise traps favoured by grad students (essentially a glorified tent) to the height of simplicity: a pane trap, which is, in essence a suspended window.
Vane trap (Hines & Heikkenen,1977) via Simon Leather
The one that really caught my eye however was the vane trap, this has been used repeatedly for decades and consisted of two flat pieces of material slotted into each other, the resulting ‘cross section’ is then surmounted by a protective ‘plate’ (although in some instances it really is just a plastic plate) with the whole assembly slotted into a funnel which is connected to a collection pot.
What attracted me to it was that it was simple in design, durable and presumably cheap to make, and due to its hanging design, fairly inconspicuous.
My first challenge was to source materials, I would need a funnel, a reservoir, a strong lightweight material to construct it from and some way of connecting it all together. More importantly, it would have to cost no more than a crisp 10 pound note.
My first bit of inspiration hit me, quite literally, on a windy March morning in the form of a discarded estate agents sign. It had worked itself free and had subsequently made its escape across my front garden. These are made from a material called ‘Correx board’ and are strong, lightweight and more importantly, easy to cut with a craft knife.
This one sign easily had enough material to construct one trap and the best part was: It cost me nothing.
Searching for ‘large plastic funnels’ online wasn’t nearly as constructive as one would imagine, many being metal and as a result, expensive and difficult to customise. After some extensive trawling and a bit of procrastination I eventually found what I needed, a 25.5cm diameter plastic funnel, from a home brewery website. When it arrived all I had to do was remove part of the spout with a dremel (although a hot piece of wire or a hand saw would also work).
This funnel is awesome because it has no internal ridges for filters and be can be purchased here at Biggerjugs
To connect these materials together I decided to use thin gardening wire, mainly because I found some left in my shed, but it also had the added benefit of being easy to unwind and remove should I have to made adjustments or emergency repairs. To attach this all I would need to do was drill a few holes in the plastic materials I had.
Enough wire to make about 5 traps
For the reservoir I would use another re purposed material. Thanks to my girlfriends recent health kick our house was full of giant Greek yogurt tubs, with a little modification (i.e a hole cut in the lid) it was perfect!
These tubs are available at Lidl and Aldi
CONSTRUCTION WAS FAIRLY SIMPLE:
I largely made up proportions as I went, but here is a basic blue print of what I cut out, the overlap at the bottom is usually about 2 cm each side of the funnel opening, but this can be scaled up or down depending on the size of the trap wanted and the thickness of wire used.
First cut out the pieces using a Stanley blade or craft knife, It easier to cut along the grain, but it also makes it slightly more prone to cracking later on, so where possible cut against the grain to provide added support
I cut two square pieces so I could repair another trap I had
2. Using a dremel, hot wire or drill, cut down funnel spout to required length
3. Using a dry wipe marker mark where holes need to be made on Correx board, drill holes in the required places.
4. On funnel make a mark either side of where you want the vane to sit (give clearance so get the wire through. On a 25.5cm funnel diameter I marked 2cm either side of where the vane would sit).
5. Drill holes in funnel using a wood drill bit (the point allows it to stay in place better)
6. Slot 2 cross sections together into funnel opening, trim with knife if necessary.
7. Thread wire through one hole, through the vane and out the closest hole, twist both ends together
8. Repeat for other holes
9. Place square lid on top, thread wire on the external 8 4 holes first, use 4 pieces of wire (we will twist them all together at the end).
10. Thread the inner holes with wire (with the vane section in the centre) for each side at the top, twist both ends together
CHECK TRAP IS STURDY AND THE SECURE, TWIST AND TRIM ALL WIRE.
Voila you have one vane trap! Now to make the collection chamber!
TO MAKE THE RESERVOIR
First take your pot and draw a circle slightly smaller than your funnel spout opening.
2. Next, using a Stanley or craft knife carefully cut a hole in the top
3. Using a drill bit (or hot skewer) make a 2 holes (opposite of one another) in the outer rim of the pot. Do not pierce the actual pot otherwise your specimens may leak out!
4. Thread the holes with a length of wire long enough to reach the side of your funnel, where you will thread it through the wire holding it to the vanes. Do this for each side.
YOU NOW HAVE A FUNCTIONING VANE TRAP, ALL YOU HAVE TO DO IS FILL THE CHAMBER WITH PRESERVATION FLUID OR BAIT AND YOU ARE READY TO GO!
My fleet, ready to be deployed!
Hopefully this has been some use, there are obviously many different ways to get the same results, The total cost of these traps is around £5, and they are very durable and due to wire, it is very easy to replace damaged panels.
My original one has lasted 2 years in the field, and despite some minor repairs is still going strong!
I have done a follow up post in regards to preservation fluid choices HERE.