How to make a small pit trap for insects

This is all the equipment I'll need to install small
pit traps to catch insects.
Photo by Brad Sylvester, copyright 2011, all rights reserved

It's easy to go outside and find a new bug or bird for this blgo at this point, but there are huge numbers of creatures that simply can't be spotted that way. One such group is the nocturnal creatures. Those that come out only at night, under the cover of darkness.

To find these creatures, I could go out at night and look for them. In the dark, I'd have pretty poor luck because my aeyes have not evolved to give me good night vision. While I might find some things if I knew exactly where to look for them, there woudl still be many more that I would miss.

To try to get a good look at some of these, I'm going to use various types of traps. Traps are placed where the creatures, in this case bugs, might be expected to travel during the night. The trap's purpose is to collect and hold the bugs until I can come and see them first thing in the morning. Bug traps can be very imple to very complex. Over time, I'll use many different kinds and I'll explain each one.

Today, I installed a simple pit trap for insects. Pit traps are generally non-specific. that means they don't attract a single species with the use of special bait or some other lure that won't pull in any non-target species. Pit traps catch whatever happens to come along and fall in. For a very small ground pit trap, like the one I'm using today, that will mostly mean insect, but it's possible that it could catch a small mouse, toad, frog, or even a small lizard. Whether it could hold each of them would depend on the animal's size.

For my traps I'm using small plastic containers that are about six inches deep, have smooth vertical walls, and an oval shaped opening that measures roughly one inch by two inches. Glass jars also work grea, especially if they have an undercut shape so that anything trying to crawl out from inside not only has to scale vertical surfaces, but has to actually crawl upside down to escape. I'm hoping the very smooth, low friction sides of these plastic containers, combined with the narrow cross section will keep most bugs inside.

The installed insect pit trap
Photo by Brad Sylvester, copyright 2011, all rights reserved

To install the trap, I simple dig a hole and place the container inside so that the lip of the container is flush with the surface of the ground. I replace any ground cover that was there around the outside of the hole so that it seems just like any other area of the forest floor. I do not cover the hole.


I'll place several of these around the same area. Because they are small, they don't cover mcuh territory and adding several helps increase the odds that they will fall in the path of something during the night. Of course, they work all day long as well, diurnal creatures can fall in just as easily as nocturnal creatures so checking both in the mornign and at dusk helps me figure out what I've caught by determining when it was active and fell in.

You should check the weather when using pit traps. They can fill with rainwater and drown water is inside if the weather is bad. Not only is it unnecessary to kill the bugs, but draowning and waterbloating can sometimes make them more difficult to identify as it can distort the size and shape of the body. If the forecast calls for rain, cover your pit traps to keep water out of them.

Another hazard of these kinds of traps is that even after one bug is caught more can fall in. If you get bugs with an adversarial relationship, you might be left with pieces of dead bugs or only the survivor of the night's encounters - another undesired outcome, but one that's more difficult to prevent.

I use deep, narrow containers because it makes it more difficult for winged creatures to escape. many of them don't fly vertically or at a steep climbing rate, so they bump into the wall and fall back down before they gain enough height to escape. The same principle applies to jumpers.

I installed these traps today, August 3rd in a wooded section of the yard as you can see from the photo below. It's a very small clearing that has a number of ground plants in addition to leaf litter. The ground around the trap is dry and solid, though moist as you'd expect from a leaf-covered forest floor. If I were putting out many traps throughout the woods, I'd number each one and record the type of habitat in which it was placed. Weather condition, temperatures, the type of vegetation near the trap, and time of year would all be variables that might cause each trap to catch different species of insects - or nothing at all.

I'm planning to leave these traps out for an extended period of time checking twice a day to see what we get. Choose one of the "follow" options from the side panel to learn what I catch.