Aquatic Invertebrates of Montana

Lindgren Funnel Trap

This trap was designed for research on bark beetles. Beetles attempting to land on the trap often slip and then use the old fold-and-drop trick, which leads them through the funnels and into the catch area. When these are set near streams or lakes, they frequently take many adult stoneflies and caddisflies as these also tend to fold-and-drop. I have found them most useful in our high mountain streams and seeps. These are often difficult to access, prone to bad weather and they have many species, often with short emergence periods.

I replace the normal catch container with a 2 liter plastic soda bottle. The bottle has the top cut off and it has 2 or 3 plastic grommets secured near the top. I attach the bottle to the lower funnel with a stout, but flexible plastic-coated wire. For periods under a month, I use soapy water with a little formalin to hold the catch. For long term use some antifreeze (ethylene glycol or propylene glycol) might be needed. I still add formalin as it keeps the catch in better shape and deters animals that might be attracted to the catch or to the antifreeze. The large bottle attached with wire keeps the catch and the chemical safely contained.

I frequently bait these traps with turpentine in a small plastic soda bottle attached to the trap. This attracts many species of interesting forest beetles as a bonus- if you like them. The traps should be kept clean for best results. The catch is very seldom flooded in our forests during the summer. The catch is usually in excellent condition and very clean, except perhaps for pine needles. These traps rarely take any vertebrates- I have seen 2 chipmunks and 1 frog in several thousand trap-days.

Lindgren Funnel Traps are built in lengths of 4, 8, 12 and 16 funnels with the cost ranging from about $20 to $45. I like the longest traps best. They are available from: