Third Grade Integrated NGSS
Life Cycles, Growth and Development

 

Comparing beetle characteristics and investigate why native California ladybugs are disappearing.

THIRD GRADE - BEETLES (COELOPTERA)

OBJECTIVE

·         Exploring different type of beetles.

·         Observing stages of ladybeetles


VOCABULARY:

·         Elytra

·         Forewings

·         Hindwings


MATERIALS:

·         Life cycle models of ladybeetles and stag beetles

·         Plastic models of beetles

·         worksheet beetle match

·         http://www.lostladybug.org

·         https://www.youtube.com/watch?v=aCWk8nYGfyg&feature=youtu.be



BACKGROUND:

The main distinguishing characteristic of the Coleoptera (sheath-winged) is the
hardened forewings (elytra) six legs and antennae. In some cases the forewings are reduced.  The “sheath" refers to the elytra which forms a protective covering over the membranous hindwings and the relatively soft dorsal abdominal wall.

All beetles have complete metamorphoses, i.e. egg-larva (several instars)-pupa- adult. It is that feature, complete metamorphosis, in combination with the elytra which characterizes insects of the order Coleoptera.

In addition to providing food for amphibians, reptiles, fishes, birds and mammals, a role which they share with most other insects, beetles play other important roles in the environment.   Some beetles are pollinators, decomposers; some feed on dung; some feed on other invertebrates, some beetles are parasites, and some eat fungi.   Some beetles control organisms that ruin human crops like ladybugs, and other beetles like the weevil destroy crops (cotton).

PROCEDURE:

1.    Go over the parts of a beetle.  Beetles go through complete metamorphism and the different stages can easily be mistaken for another group.  Unfortunately the only way to recognize their appearance is to look for them and check on the internet.

2.    Look at the models of the ladybeetle and stag beetle.  Notice the big difference in forms, which make identifying beetles very difficult.

 

3.    Look at the plastic models of other adult beetles.  Students use the worksheet and try to identify the 7 beetles on the sheet.  Look for characteristics that might help to identify.  Ask students to describe each of the models.  May want to put information on the board.  This helps to direct students observational skills.

Compare and contrast each of the stages. 

Life Cycle of Ladybug or ladybeetle

 

Eggs:  Ladybug eggs are pale yellow and very small. The mother ladybug lays them on the underside of a leaf for protection.  As many as 300 ladybug eggs are produced at a single time.  They usually hatch in 3-5 days.

Larva: Once hatched, a ladybug egg becomes a larva.  This baby ladybug has a long body with six legs.  The larva eats aphids and grows for about 3 weeks until it turns into a pupa.
Pupa:  The pupa is the final step before the baby ladybug is fully grown.  It is wet and soft, but hardens as it dries.  This stage lasts from 3-12 days until the pupa become an adult.

Adult:  Adult  ladybugs develop bright colors soon after their pupa stage.  Ladybugs live from 3-9 months, sleep through the winter and awake in spring. 

 

Life Cycle of Stag Beetle

 

Eggs:  Female stag beetles carefully prepare the ground by digging into the soil before laying 30-90 eggs near rotting wood, which will provide food once the eggs hatch.  It can take about three weeks for the eggs to hatch.

Larva:  Stag beetle larvae break from their eggs by cutting the shell.  They are C shaped and feed on rotting logs near where they hatch.  It takes about two to seven years for them to mature, during which time they feed on decaying wood and grow larger.

 

Pupa:  Once a larva reaches its full size of 3 inches long it prepares a safe spot deep in the ground for a cocoon.  In the cocoon it undergoes metamorphosis.  It may leave its cocoon, but it will stay underground until spring before emerging as an adult stag beetle.

 

Adult:  After emerging from the ground, adult stag beetles begin seeking a mate since they only live for a few months.  Adult male stag beetles are known for their large, impressive jaws, which are used for wrestling other stag beetles over food or territory.  Female stag beetles spend mos their time search for a nesting site.


4.     If you have time, you may want to concentration on the Ladybeetle or Ladybug -  Across North America ladybeetle species composition is changing.  Over the past twenty years native ladybugs that were once very common have become extremely rare.  During this same time ladybugs from other parts of the world have greatly increased both their numbers and range. This is happening very quickly and we don’t know how, or why, or what impact it will have on ladybug diversity or the role that ladybugs play in keeping plant-feeding insect populations low.  We're asking you to join us in finding out where all the ladybugs have gone so we can try to prevent more native species from becoming so rare.

https://www.youtube.com/watch?v=aCWk8nYGfyg&feature=youtu.be

Ladybug, ladybug, ladybu-u-ug
Ladybug, ladybug, ladybu-u-ug 

Let's go find a ladybug
They live in gardens, weeds, and shrubs
There are 5000 species worldwide
The number of spots identifies the kind
Ladybugs are beetles with six legs
Ladybugs can be yellow, orange, pink, brown, black, white, blue or red

Ladybug, ladybug, ladybu-u-ug 

Ladybugs have two sets of wings
Antennae help them smell, touch, and taste things
Ladybugs chew from side to side
If it's cold or dark, they might not fly
Ladybugs roll over and play dead
Ladybugs release a chemical that tastes terrible in self-defense

Ladybugs have important jobs
Eating aphids that destroy our crops
We need lots of different kinds
But some species are now hard to find
Ladybugs, they need us to conserve
Ladybugs, we will protect your habitats
and take care of the Earth

Ladybug, ladybug, ladybu-u-ug
Ladybug, ladybug, ladybu-u-ug
Ladybug, ladybug, ladybug-u-u-ug
Ladybugs



 




 

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