Trunk traps are a novel and effective technique for intercepting ants on tree-trunks.  Constructed from a 2 litre pop bottle and a urine sampling cup, the components for the trap are cheap to buy and easy to assemble.

1) beg, borrow or buy some 2L pop bottles from a local recycling depot.

2)Purchase some urine sampling cups from a medical supply company.  Buy twice as many as needed because each cup will need two lids.

3)Cut the bottle in the general fashion shown here.

4) Cut a 30mm (1 1/8 inch) hole in a urine sample lid.  Then roll this over the plastic flange on the neck of the pop bottle.

Your Done!

In the field just attach the bottle to a tree trunk with a couple of 1/4 inch wood screws.  Add your preservative (e.g., propylene glycol/water mix) to the urine container and screw into place.