[Year/Subject] 3rd Year, Science

The Body of a Dragonfly

Objectives[Course Name] Body and Life Cycle of Insects

Optimum Season
If the worksheet “The Body of a Dragonfly Larva” is taken into account, dragonflies should be caught and observed between
May and October, when hawkers, common dragonflies and damselflies are present in large numbers, after observing dragonfly
larva between April and May. Alternatively, dragonflies can be observed first, followed by observations of well-developed
dragonfly larva between November and March.
Items to PrepareButterfly net: to catch dragonflies  Digital camera: to photograph dragonfly larva and dragonflies
Magnifying glass: to observe the dragonfly’s compound eyes
Dragonflies are living animals withexoskeletons that children can handle easily
and form valuable teaching aids. Observing
the body structure of dragonflies can beconsidered a supplementary exercise forthird-year pupils who study “The Body ofan Insect” in their first semester.
Dragonflies are common insects that live inthe same ecosystem as humans. They can becaught between spring and the start ofwinter around areas such as ponds, fields
and rice paddies. Provide pupils with theopportunity to catch a dragonfly as part oftheir study into experiences with the naturalenvironment.
When catching and observing animals in thewild, make sure to take note of thefollowing data.
How to catch dragonflies
Dragonflies can be difficult to catch as they
can fly around very tactfully and havewell-developed vision. They do, however,
have blind spots towards the rear where thehead joins the body, and underneath near
their mouth. They can be caught withrelative ease by swinging a butterfly net
upwards and at an angle from the rear.
How to take dragonflies home
Rather than placing dragonflies that havebeen caught into a breeding case, theyshould be placed in a “triangular paper”
folded out of tracing paper or printing paper,with care taken to avoid direct sunlight.

Increase the pupil’s awareness of “The Body of an Insect” by capturing and observing dragonflies in the wild.
Comparisons can be made between the “Relationship between the position of the left and right eyes” and the “Shape of theforewing and aft wing”, an important factor for classifying insects, which can enable pupils to think about different families
of insects.
Increase the pupil’s awareness of local environmental conservation by experiencing nature around familiar water
environments.
Classifying different types of dragonflies
can be extremely difficult. In thisexercise, ecological and morphologicalcomparisons will be observed to enablepupils to think about different families ofdragonflies.

Observing dragonfly wings when they are stationary
Dragonflies that live around ponds and have fully closed wings when they arestationary belong to the coenagrionidae family, while those that have partiallyclosed wings belong to the lestidae family; both are part of the zygoptera
suborder. Members of the odanata order, including aeshnidae, orthetrum andsympetrum, have their wings almost fully open in a horizontal position.

Example answers (partially entered)Let's have a closer look at the dragonfly’s wings when
it is stationary.

The Body of a Dragonfly
Dragonflies are often found hovering above ponds and rice paddies. It is almost as if theyare expressing their excitement at growing from a dragonfly larva to a full adultdragonfly.
Dragonflies have a sleek, gorgeous form.
Let's have a closer look at dragonflies.
 Observation date & time: Weather: Observation area: Temperature:
Write the name of each body part of a dragonfly in thecorresponding squares.

Species with wings that are spread out horizontally

Species with wings that are closed or slightly closed

Aeshnidae, orthetrum, sympetrum etc

Coenagrionidae

Observing dragonfly wings
Observe the base shape of the aft wings.
The base shape of the aft wings in families
other than the coenagrionidae are wider andhave a different shape to those of theforewings.

Let's have a closer look at the position of the left and right eyes.
Compare the shape of the forewing and aft wing.
Widen

Connected

Can you
catch one!?

Do not widen

Separated

Forewing

Aft wing

Blue-spotted emperor: male

Common skimmer: male

Relationship between the position of the left
and right eyes.

HeadCompoundeye

Common skimmer

Connected

Emerald damselfly

SeparatedThoraxBlue-spotted emperor:male

Front leg

Shape of the forewing and aft wing.

Different, aft wings larger thanforewings
Different, aft wings larger thanforewings

Almost the same

What conclusions can be made after making theseobservations?

AbdomenAntenna

Middle leg

Blue-spotted emperor

Connected

Emerald damselfly: maleThe relationship between the wings, position of the left and right eyes, and shape of theforewing and aft wings of the aeshnidae and orthetrum (and sympetrum) were similar,
however the coenagrionidae was different. From this, we can conclude that aeshnidae

Rear legand orthetrum (and sympetrum) are closely related, while coenagrionidae is only
distantly related.

Triangular paper
Observation technique
Dragonflies that have been brought back to the classroom should be placed
into a clear Ziploc-type plastic bag and observed from the side with theirwings in a closed position. Doing so prevents damage to the dragonfly’s
wings or body, enabling them to be released without harm after observations
are complete.

Thorax, legs and wings
The thorax area of insects is divided into the “prothorax”, “mesothorax” and“metathorax”. The “front legs” are connected to the “prothorax”, the “middle legs”
to the “mesothorax” and the “rear legs” to the “metathorax”. Observing dragonflies
from the side is an extremely effective method for understanding “the body of aninsect”.

Observing dragonfly compound eyes
Observe whether the left and rightcompound eyes are “separated orconnected”. Of these three different families,
only those in the coenagrionidae areseparated.
Further discussion
While the size and shape of dragonflies inthese three families differ, those in theaeshnidae, orthetrum and sympetrum
suborders are closely related, and sharecommon behavioral and characteristic traits.
Observation shows that dragonflies in thecoenagrionidae family are only distantlyrelated. This distance relationship isexpressed by the “order” rather than on“suborder” scale. Try and allow pupils toobserve as many different types as possible
to provide them with an understanding of
this type of classification.
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