Logs provide a bounty of resources for many insects and other arthropods. In many ways, they are a rich, miniature ecosystem alive with critters of all kinds. Insects may live on, in, or under the slowly decaying wood, but there is typically little outward evidence of this diverse system unless the seemingly lifeless log is examined closely and ultimately turned over. The organisms found on or under logs generally fall into one of four basic categories: decomposers, predators, nesters, and hiders. Decomposers are organisms that feed on decaying dead organic material and in the process convert it to hummus, which in turn improves the soil and ultimately provides beneficial nutrients back into the system for other plants and animals to use. The following are a few decomposers: earthworms, sow and pill bugs, snails, beetle grubs, etc.
The diverse array of decomposers found under and around a decaying log attracts many potential predators that seek to take advantage of the available prey. Some examples include ground beetles, earwigs, and so on.
The next group of organisms found in a decaying log are nesters. Like miniature developers and architects, they tunnel through the log as well as the soil beneath, often creating an apartment-complex-like assemblage of chambers for their developing colony. Both termites and ants are nesters that inhabit dead wood. Their activity helps break down the log over time and provides additional holes, cavities and food for other organisms.
Logs also provide valuable shelter to many organisms. Many insects and arthropods are active at night and seek refuge by day in cool, dark, and often moist places. Such locations help minimize desiccation (drying out), provide protection from temperature extremes, and offer ideal hiding places to avoid detection by larger predators. Beyond such temporary occupation, logs also provide longer term habitat for hibernating organisms that seek to overwinter. Many wasps, bees, bugs, millipedes, and even some moth caterpillars, such as woolly bears, survive the cold winter months by hiding out in such sheltered locations.
How to Hunt for Bugs in Logs
So now that you know some of the organisms found on, in, and under logs, it’s time to start exploring. It may be useful to have a magnifying glass and a wide-mouth plastic jar with a lid before heading outside. Once you find a log, take a few minutes to look it over carefully. Some organisms worth observing might be on or around the log. Then, carefully roll the log over. Be prepared to look quickly, as many organisms will rapidly scurry when disturbed. Use the plastic jar to temporarily capture any critters for closer inspection. Studiously examine the underside of the log and the ground beneath for insects and other arthropods. You may wish to use the magnifying class to study some of the more minute organisms. When you are done looking, always gently return the log to its original position, so you don’t significantly disrupt the valuable habitat. Then move on to the next log and continue the process. You will be amazed at all the critters you’ll find!
In Leaf Litter
As you walk through a forest, take note of all the fallen leaves on the ground. This blanket of old, dead leaves and the associated twigs, discarded blossoms, fruit, and shed bark is actually a habitat all its own and home to a surprising variety of invertebrates. Such leaf litter is critical for creating healthy, moist, and nutrient-rich soil for the entire ecosystem. It also harbors a rich array of fungal and microbial life. Thus, leaf litter, just like a decaying log, serves as great habitat for a wide range of insects and other arthropods. Just like with logs, it provides food and protected, often highly moist sites that support decomposers, predators, nesters, and hiders, creating a rich microcosm of life. Earthworms, pill and sow bugs, some fly larvae, snails, slugs, earwigs, and many others feed on dead or decaying plant material and can be prevalent in and under leaf litter. Predators or scavengers found in leaf litter include wolf spiders, some adult beetles and their larvae, ants, millipedes, cockroaches, centipedes, and earwigs; many are active by night and spend the daylight hours hidden under leaves in protected and moist locations. Many of these same organisms nest or reproduce in this environment. Lastly, leaf litter literally provides layers of protection to temporarily shelter critters, enabling them to mitigate temperature fluctuations, avoid desiccation, and escape hungry predators. It also provides longer-term protected sites in which to successfully overwinter.
How to Look for Insects in Leaf Litter
Similar to a dead log, leaf litter initially appears lifeless until you look more closely. Once again, it may be useful to have a magnifying glass and a wide-mouth plastic jar with a lid, as well as a small garden trowel and a plastic bowl before you start. Find a spot in your yard or nearby woods and get down and simply watch for a bit. You may see or hear a variety of critters crawling over or in the leaf litter. Then, use your hands or the small garden trowel and gently start pulling away the layers of leaves and debris, watching closely at what you uncover. The plastic jar can be used to temporarily capture any small organisms for closer inspection. Continue to uncover the debris until you get to the decomposed organic material and soil beneath. Using the trowel, now slowly dig down taking a few small scoops and placing them in the bowl. This will allow you to inspect that moist material in greater detail to see what life lies inside. When finished, return the organic material and soil to the same location and be sure to release any captured critters. You may wish to repeat the process at night and simply observe the ground to see a wider array of active organisms.
Beneath Tree Bark
Dead trees, stumps, and decaying logs typically are covered with loosening bark. While many insects and other arthropods live in or under dead or decaying wood, some can also be found under bark. In many ways, bark provides the same sheltered environment and resources as leaf litter and the area beneath logs. Similarly, many of the same organisms can be found here. A quick word of caution, however: Be very careful around dead trees or large stumps, as they are often unstable. Limbs or large pieces can fall and cause serious injury.
How to Find Insects Under Tree Bark
Once a safe tree, stump or log has been located, start by observing the exterior for signs of life. Do you see any small holes or other signs of activity? Then, slowly and carefully remove pieces of loose bark to see what lies beneath. Look quickly, as many organisms will quickly scuttle away from the disturbance. A wide-mouth jar is again handy, as it enables you to examine your finds. Once the bark is removed, explore both the uncovered dead wood and the back of the bark as you may find organisms on both. Some common organisms that you may encounter include ants and their brood, centipedes, sow and pill bugs, small beetles, beetle grubs, and earwigs, among many others. If you explore these sites in fall and winter, you may also discover many hibernating insects, including lady beetles and bugs.
Beyond any living critters, you will likely also see a history of activity, this can include everything from small holes and chambers to a network of small tunnels and routes that were created by from bark beetles or other wood-boring insects. The network of designs can be quite extensive and appear almost like a piece of artwork. Use the magnifying glass to examine the surface in greater detail. Dead trees and larger stumps will continue decay to further and eventually end up on the ground; continue to follow and explore these hidden resources through time as they decompose and as new organisms use or colonize them.
Looking for Insects on or Under Other Objects
While logs, large fallen branches, and leaf litter are great resources for exploring the hidden world of biodiversity, many other natural or artificial objects provide shelter and habitat for insects too. These include rocks, old boards, landscape pavers, and even flower pots. As you explore, gently turn over many of the larger objects that you find. These are great places to spot earthworms, earwigs, sow and pill bugs, millipedes, centipedes, snails, and cockroaches. Once you’re finished looking, gently return the object to its original position before moving on.
On the Ground
A great many insects and arthropods are ground-dwelling, and they spend all or some of their time foraging, nesting, or otherwise scurrying along the ground in either natural or artificial areas. The specific species and the overall diversity of organisms depend greatly on the type of environment