CRESO
Dragons of the Insect World Lesson 1

 Overview/Objectives:

Have you ever seen a "dragon" fly? What is a dragonfly and where have you seen them? The dragons around wetlands don't breathe out fire but they have many other fascinating traits, including great flying ability. These three lessons focus on the fascinating physical and behavioral adaptations of dragonflies. Students start with general observations of the adults in lesson one, become familiar with larva (nymph) and adult anatomy in lesson two, and then study a single species - the Whitetail Dragonfly - in lesson three. This common wetland visitor is used as a model to help students develop inquiry skills needed for investigating other organisms.

  • Students discuss ways they think scientists learn about animals
  • Students share their knowledge about insects and specifically dragonflies
  • Students prepare their dragonfly notebooks
  • Students describe dragonfly behavior and habitat
  • Students use observations to construct questions and write about dragonflies

Background for the Teacher:

Small wetlands, often referred to as seasonal pools, harbor a wealth of unique life forms. Animal activity in and around a wetland depends on time of year, water levels (hydroperiod), weather conditions, associated plant species, and other landscape features. Newly hatched dragonflies, for example, spend a few weeks feeding along wooded edges and in open fields before returning to streams, seeps, or ponds for mating and egg-laying. Thus, in order to understand dragonfly activity patterns, it is important to visit different habitats in different weather conditions. Adult dragonflies are best observed on sunny, warm days >650 F (180 C), since they hide in vegetation on cool, cloudy days. The adults are absent in our area during the winter, but larva can still be found even in the coldest months, thus dragonfly investigations can be conducted year round.

This lesson is designed to assess student familiarity with insects and specifically dragonflies. Dragonflies are predators that belong to a group of insects known as the odonates (Odonata Order), which also includes damselflies. Like other insects, they have three main body sections: head, thorax, and abdomen. They have two tiny antennae on the head and six legs and four wings attached to the thorax. The abdomen makes up most of the body length and has 10 segments. The hind wings of dragonflies are broader at the base than their forewings whereas the more slender damselflies have forewings and hind wings which are similar in size. Dragonflies usually spread their wings out to the sides when perched while damselflies hold their wings over their back or only partially spread when perched.

Most insects undergo complete metamorphosis (meta = change, morphe = form) which involves an amazing transformation from a worm-like larva to pupa and pupa to adult. Other insects, including Dragonflies, demonstrate a more gradual life cycle represented by less radical changes of a nymph (larva) form. Nymphs, like caterpillars, shed their skins (molt) in order to grow, but unlike caterpillars, nymphs look more like the adult with each molt. Even though dragonfly development is termed gradual or simple, the transformation from nymph to adult is nothing less than spectacular. The terms simple or gradual seem inadequate for describing the shift from an underwater nymph with a plump abdomen and tiny wing buds to an incredible flying machine that can zip around at speeds approaching 35 miles per hour.

These lessons focus on techniques used to conduct field studies rather than identification of some of the 435 or so dragonfly species found in North America. Describing physical features, associated habitats, and behaviors of an organism are important developmental steps for young scientists. Learning names will follow from a natural desire to know more about study subjects. The first lesson allows students to gain experience taking field notes. A field data sheet is provided, but students should be encouraged to pose questions and modify the data sheet to their liking. Remind students that practice and patience are keys to becoming a good field biologist.


Materials:

  • Newsprint and markers
  • Pencils
  • Dragonfly stickers or photographs
  • Notebooks (composition work well)
  • Flagging (optional)
  • A field data sheet (a guide for helping students develop their own data sheet)
  • Thermometer
  • Timers (used to determine how long dragonflies perch or fly)

Preparation:

Prepare two sheets of newsprint with the following titles:

"What are some ways scientists study animals" and

"What do you know about insects"

It will be important to spend a little time scouting the schoolyard wetland and surrounding areas for evidence of dragonfly activity. They are often seen in swarms over roadways, parking lots, and open fields. You might invite students looking for a change of pace from their normal recess activities to form a scouting party. Laying out a dragonfly route with "stop and observe stations" prior to the lesson will result in better use of time. Students can make a trail map of landmarks to be used for observation points. You can start or end at the wetland. Be sure to pick a warm, sunny day for field observations.


Procedure:

  1. Gathering background information on student ideas normally reveals expected and unexpected misconceptions. It is also surprising how knowledgeable some students are about certain topics. Place the first title, "What are some ways scientists study animals," on the board. It's not critical to keep a record of all responses. However, it is important to accept ideas without judgment, recording incorrect as well as correct information. Their responses can be enhanced over time by allowing students to add sticky notes to their initial ideas.
  2. Inform students they will be conducting research on organisms in and around their schoolyard and that you are interested in their ideas on how they might study different animals. A few leading questions might be:
    • What are some animals you might find around the wetland or in the schoolyard?
    • Are some animals easier to study than others? Examples?
    • Do scientists always need to catch or trap animals in order to study them?
    • What can you find out about an animal without capturing it?
    • Are insects animals? How are insects alike and different from other animals?
    • What are some ways you could study insects?
  3. Display the chart titled "What do you know about insects," and record student ideas. Some leading questions might be:
  • Where would you look for insects?
  • What are some ways insects move?
  • What are some ways other animals move?
  • What are some body parts insects have? Do they always have the same number of body parts?
  • Do other animals have the same body parts as insects? Examples?
  • Have you ever seen a dragonfly? Where? Are dragonflies insects?

Follow this discussion by recording some student questions about insects and specifically dragonflies.

  1. Preparing the student notebook: Composition notebooks work well for field notes. Skip a couple of pages in front for recording a table of contents. Students can decorate their notebooks with dragonfly stickers, photographs, or use their own drawings.

  1. Explain to students they will be taking schoolyard field trips in order to study dragonflies. The observation data sheet with this lesson can be copied and taped to the inside of their notebook. You may want students to produce their own data sheet after they have some field experience. Go outside and introduce students to the dragonfly observation route.
  • Go over the Dragonfly Observation Data Sheet and fill in standard data
  • Do all students know what an adult dragonfly looks like?
  • Are there different kinds of dragonflies?
  • Have students describe things they observe about dragonflies, including what they look like and how they behave.
  • Why are some dragonflies at wetlands while others are in fields or along roads?
  • Have students describe dragonfly habitats.

Final Activities:

  • 1. Allow students to share their observations and questions on chart paper. Students can use sticky notes to add information to the chart as they make new discoveries.
  • 2. Try different writing prompts and encourage students to include diagrams.

Examples:

  • Describe a day in the life of a dragonfly. Be sure to include abiotic (e.g., air temp, high winds, or a rainstorm) and biotic (e.g., kids trying to catch me with a net! or other dragonflies chasing me) factors in the story.
  • "The Day I Had a Head-on Collision with Duke" or "The Day Butch Tried to Take Over My Territory."
  • 3. Explain to students that in the next lesson they will be studying the life cycle and anatomy (different parts) of a dragonfly.
  • 4. Some time should be spent discussing the three big things that animals must do in order for the species to survive. These themes can be used for all animal studies.
  • Find food
  • Keep from becoming food
  • Reproduce

Extension: A useful homework assignment is to have students collect dead dragonflies. They should carefully place them in zip-lock bags and store them in the refrigerator. These specimens can be used for future lessons. Label each bag with student name, date, and where found.