Gardens are full of interesting creatures that squirm, crawl, and fly. Your students can become garden detectives and try to discover who some of these visitors are and what they're up to. Challenge your kids to use their eagle eyes (and a hand lens, if possible) to look for signs of insect and other animal life. Don't forget to look in the soil, under leaves, on flowers, and in the air. After all, many creatures carry on their lives out of sight. What is the largest animal they find? The smallest? The most interesting? Encourage them to write about and draw pictures of their findings. Have them observe carefully to learn as much as possible about each living thing they discover: What does it feel like? How does it move? What does it eat? How does it interact with other living things? Where does it rest or hide? Does it seem to help, hurt, or not affect garden plants? Who visits the flowers? Are some flowers visited more often or only by certain creatures?
Starting with Student Conceptions
Consider launching insect investigations by having students share their ideas about insects and plants. As individuals or a class, they might write a description of insects, create word webs, and/or draw insects using their current conceptions. Ask questions that prompt students to reflect in greater detail. If they mention that insects have legs, for instance, ask them how many and where they're found. Have them brainstorm and list what they know about how insects interact with plants. This will give you and your students something to revisit as they later explore insects and plants up close.
As students have multiple opportunities to observe and contrast garden insects, dead and alive, they can compare their findings with their ideas and predictions. They can also begin to generalize about insect features and behaviors. (Make sure to have students keep alert for clues when reading insect-related fiction.) Tip: All insects have a hard exoskeleton (covering the outside of the body), three body parts (head, thorax, and abdomen), three pairs of legs, antennae, and compound eyes. Some insects also have wings.
As students observe, draw, and gather garden insects, challenge teams to use their own criteria to group their creatures based on similarities and differences. Next, have teams look at one another's groupings and try to guess which criteria were used. Follow up by having students research how scientists classify insects, then compare those categories with their own. (Insects are grouped into orders according to physical characteristics and life cycles. Beetles, for instance, are in the order Coleoptera, the members of which are distinguished from other insects by their hardened outer wings that form two halves when folded, two pairs of wings, chewing mouthparts, and complete metamorphosis.)
Adapt and Survive!
What kinds of adaptations do insect prey have to help them avoid predators? Some are camouflaged to prevent detection. Others are flashy: Bad-tasting insects, such as milkweed bugs, which concentrate bad-tasting compounds found in milkweed sap, sometimes have vibrant coloring, which serves as a warning to potential predators. Lady beetles also have distasteful fluids. Other bright insects mimic other bad-tasting ones, with the same result. Consider having your students design an insect that could blend into a particular environment, real or imagined.
Gather or purchase native or garden plants and have student teams describe the flowers' characteristics, such as color, odor, shape, and depth. Challenge them to come up with the likely characteristics of each plant's pollinator, then observe the plant in its natural setting and test their predictions by looking for evidence.
Create, or have groups of students create, a garden insect scavenger hunt. Your items will vary depending on when during a plant/insect unit you introduce the hunt, your grade range, and your garden or habitat type. Here are some sample items: Find ... a ground-dwelling beetle ... damage from a "sucking" insect ... a pollinator ... an insect egg or egg case ... an insect in a larval stage ... a predatory insect ... an insect-insect interaction ... an insect feeding on a plant. Students might carefully collect sample items and release them after the hunt, or simply draw or describe what they've found for each item.
Something to Chew On
Consider challenging your sleuths to infer what's bugging different plants by focusing on leaves. Besides seeing actual insects, what signs can students find that indicate an insect has been at work? What can they infer about different types of insect mouthparts by looking at a variety of leaves? You might use the following information to guide your questioning or share it with students, as appropriate.
Insects that have chewing mouthparts leave telltale holes in leaves, as though something has taken a bite (a grasshopper, beetle, caterpillar, or other chewing insect probably did!) Students may notice that some leaves seem to have small spots or speckles across their surfaces. In that case, an insect with piercing/sucking mouthparts is likely the culprit. Aphids and other insects with a long, thin proboscis pierce through leaves, then suck the nutritious plant sap, weakening the leaves.
Although they don't damage leaves, insects that suck nectar from flowers (or juice from rotting fruit), such as butterflies and moths, do so using a siphon action. After drinking nectar, such an insect can coil up its long proboscis until it needs it again.