Ground-Nesting Insects
A great number or insects and other arthropods also nest in the soil. This includes some 70 percent of the native solitary bees in North America as well as many wasps and beetles. In turn, velvet ants search out and parasitize the nests of other insects, often ants and wasps. Fire ants and pavement ants are ground nesters, creating extensive subterranean colonies and actively foraging for food in the surrounding area. Carpenter ants typically nest in dead wood but commonly also excavate the soil beneath fallen trees or decaying logs. Yellow jackets take advantage of existing animal burrows or other cavities to form extensive underground nests. Mud dauber wasps frequent moist ground to acquire the raw materials to build their adobe-like nests. A number of organisms, such as earthworms and slugs, live much of their lives in the soil itself but can often be found aboveground periodically. Rainy days are a great time to spot earthworms, for example.
Some insects also feed at or near ground level. Male butterflies are one example; they regularly visit wet sand, gravel, mud puddles, or animal dung to gain nutrients. Many butterfly and moth larvae will periodically be seen wandering along the ground. When you see them doing that, they’ve finished feeding and are looking for suitable and protected places to pupate or spin a cocoon—or in search of places to overwinter, in the case of the woolly bear. In some cases, the larvae of various insects, including those of regal moths, imperial moths, and tomato hornworms, actually pupate in the soil.
While it may not be the first place you think of to look for insects and other arthropods, the ground is actually a habitat bustling with life of all kinds. Spend some time looking down and you will be amazed at what you find.
On Plants
Plants provide vertical structures in the environment, and they range from ground-hugging shrubs to trees that can reach hundreds of feet in the air. This, combined with the sheer diversity of plant species, provides a wealth of resources for insects—everything from food to shelter—and so plants support an almost countless variety of invertebrate organisms. A large percentage of insects and other arthropods are herbivores. They feed on, or in, every conceivable plant part, from stems, sap, and leaves to roots, flower buds, and fruit. We may be most familiar, though, with the critters that feed on leaves. Their activity is often extremely visible, resulting in noticeable leaf damage. However, it is important to note that the food preference of adult and immature insects often varies tremendously. Butterflies and moths are good examples. As caterpillars, they readily devour leaves and other plant parts; as adults, they feed exclusively on liquid food resources, such as flower nectar, tree sap or the juices from fermenting fruit. A variety of beetles, including tortoise beetles, Japanese beetles, may beetles, and grapevine beetles, also feed on leaves, while some of their larvae or grubs feed underground on plant roots. Grasshoppers, katydids, slugs, snails, and walking sticks are generalist herbivores, nibbling away on the leaves of various trees, shrubs, grasses, or herbaceous plants. Many bugs have piercing-sucking mouthparts that are used to pierce plant tissues and siphon out sap. These include treehoppers, tarnished plant bugs, green stink bugs, large milkweed bugs, leafhoppers, planthoppers, aphids, and cicadas, among many others.
Plant-Based Predators
The tremendous bounty of herbivorous critters attracts an equally rich diversity of predators seeking a hearty meal. These include active hunters, such as paper wasps, cicada killers, robber flies, jumping spiders, mud daubers, lady beetles, and spined soldier bugs, to various scavengers, including carpenter ants and fire ants. Plants also harbor several sit-and-wait ambush predators. The praying mantis is one example; it is one of the most charismatic carnivorous insects on the planet. Similarly, many spiders use plants as support structures for the large webs that help them capture insect prey. Still other insects may nest in or on plants, occupying shelter sites under leaves, in hollow stems, or in existing cavities. A few examples include paper wasps, leafcutting bees, and bald-faced hornets. They are equally useful as secure, protected sites on which to spin a cocoon or form a chrysalis. Plants can also provide the raw materials for nest construction, camouflage, or even body armor. Examples here include leaf cutting bees, which line their nests with pieces of leaves, or bagworms, which cover their bodies with sticks and other plant debris that they spin together with silk, creating a protective disguise.
How to Look for Insects on Plants
Carefully inspecting plants will reveal all sorts of unusual critters. Look for signs of feeding to start, and be sure to inspect all areas of the plant, not just the leaves. You can also put down a white sheet or a cloth beneath over-hanging branches or taller plants and beat the vegetation with a stick. This will knock off many organisms onto the sheet below where they can be more closely observed or temporarily captured. You can also use an insect net to vigorously sweep through grasses and other vegetation and then look inside to see what critters have been dislodged.
Insects on Flowers
Flowers provide an abundance of sugary nectar and protein-rich pollen. These abundant and attractive food rewards attract insects, which help pollinate plants. In many ways, flowers are their own miniature ecosystems; they draw in a wide variety of insects from the surrounding environment, often in large numbers.
Predators Amid the Blooms
The resulting abundance of insects subsequently attracts other organisms with completely different intentions—to prey on the unsuspecting visitors to flowers. These include a wide variety of spiders, robber flies, assassin bugs, ambush bugs, stink bugs, and green lacewings, as well as larger, more charismatic predators, including praying mantises and even dragonflies. As many of these predators sit and wait for passing prey, they can be camouflaged, making them a challenge to spot. Careful and close observation is often needed.
Herbivores on Flowers
A variety of plant-eating insects can be found on or at least near flowers. They feed on the leaves, stems, buds and even flowers of their host plants. Within this mix, you may encounter various caterpillars, beetles, true bugs, aphids, thrips, and grasshoppers. Additionally, you may notice scavenging ants or the larvae of green lacewings and lady beetles, which are attracted to the aphids or scale insects that can be common on many plants.
Looking for Insects on Flowers
Without a doubt, flowers often teem with life and are a great place to start exploring. Before you look up close, stand back and observe for a few minutes. If the flowers are attractive, you should notice a fair amount of activity in the form of insects coming and going. Particularly noticeable insects include bees, wasps, butterflies, and day-flying moths. As you look more closely, you may notice a variety of smaller and less obvious critters, such as beetles and flies. The vast majority of these insects are attracted to the copious quantities of nectar and pollen, and they are generally classified as pollinators.
As you start looking, you will quickly notice that different flowers attract different organisms and that some species, types, and colors of flowers are much more attractive than others. Planting a flower garden in your yard or at your school is a great way to help provide food and habitat for many of these beneficial organisms, and it's an easy way to bring bugs to you, making observation easy.
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