How Does a Beetle Eat?

Target Audience

2^nd and 4^th Grade

Estimated Time for Lesson

2.5 hours

photocredit: Diana Parkhouse (unsplash.com)

Overview

This lesson is designed to get students thinking about structure and function of the different parts of an insect’s body and how those parts work together to support survival, growth, behavior, and reproduction. Students explore this phenomenon by observing ladybug behavior when searching for food and eating. They also look attexts and media that help them better observe and understand how insects eat and the structures that are involved.. Once students are familiar with the structures that make up chewing mouthparts in insects, they can explore how other insects in an ecosystem might feed on different things and participate in a mouthparts design challenge in which they work in teams to imagine and design insect mouthparts that are structurally adapted to feed on different types of food. Students share their findings with the rest of the class and are introduced to the variety of structures found in insect mouthparts.

Background and Introduction to Study Insect

Ladybugs (Coleoptera: Coccinellidae) are insects that are common in the United States. They are insects, meaning they have an external skeleton, three main body parts (head, thorax, abdomen), a pair of antennae, and six legs. Ladybugs are not true bugs but are in the beetle family. and Their first pair of wings is hardened into wing covers called elytra. The elytra cover up theirhind wings.

Most ladybug species are predatory and considered beneficial for plants and people because they feed on plant pests like aphids and scale insects. A few species feed on pollen or plants and can be considered pests (Cunningham, 2007). Ladybugs feed using chewing mouthparts called mandibles. In order to feed, in addition to their mandibles they have an upper lip (labrum) and lower lip (labium) as well as palps to help them sense and taste their food.

There are a variety of different types of insect mouthparts. Insect mouthparts are generally considered to be adapted for either chewing or sucking. Variations include chewing, piercing-sucking, siphoning-sucking, sponging, and lapping (Triplehorn & Johnson, 2005).

Learning Objectives

 

Students will…

• Make observations of insect behavior and external structures on an insect’s body and explain how those structures help an insect grow, survive, and reproduce
• Explain how the different structures on a ladybug’s body work together as a system
• Develop a model of insect mouthparts
• Describe how insect mouthparts work together to help an insect eat.

Performance Expectation	Students…
4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.	Observe ladybug behavior and interactions with other insects in videos Explain how the different structures on a ladybug’s body work together to help it survive.
Science and Engineering Practice
Developing and using models	Develop a model of insect mouthparts
Engaging in Argument from Evidence	Gather evidence from text and media of the structures that ladybugs have to help them eat and then use scientific terminology to explain how those different structures help the ladybug
Disciplinary Core Idea
4- LS1.A: Structure and Function: Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.	Make observations of insect behavior and external structures on an insect’s body and explain how those structures help an insect grow, survive, and reproduce
Crosscutting Concept
Systems and System Models	Describe how insect mouthparts work together to help an insect eat.

 

LS2-2

LS2.A: Interdependent Relationships in Ecosystems

Science and Engineering Practices

Developing and Using Models

Modeling in K–2 builds on prior experiences and progresses to include using and developing models (i.e., diagram, drawing, physical replica, diorama, dramatization, or storyboard) that represent concrete events or design solutions.

• Develop a simple model based on evidence to represent a proposed object or tool.

Structure and Function

• The shape and stability of structures of natural and designed objects are related to their function(s).

Teacher Lesson Plan Instructions

 a. List of Supplies/Materials needed

• A list of suggested books about ladybugs to have on hand for this lesson:
• “Are You a Ladybug” by Judy Allen and Tudor Humphries
• “A Ladybug’s Life” by John Himmelman
• “The Life Cycle of a Ladybug” by Colleen Sexton.
• “Ladybug At Orchard Avenue” by Kathleen Weidner Zoehfeld
• A copy of the two worksheets for each student: How Does a Beetle Eat and Mouthparts Design Challenge.
• Access to the internet to show several YouTube videos.

b. Step by Step Instructions for Lesson

Part One (15 – 20 minutes)

Ask students to imagine they are eating a sandwich. You can ask for a couple of volunteers to act it out, have them all eat an imaginary sandwich at their desk, or provide them with something to actually eat, such as a piece of candy.

After a few minutes of students trying this out, ask them to turn and talk to a partner about the process that they just went through. What parts of their body did they use in order to eat the “sandwich”?

Pull the group back together and ask students to help you understand the structures that people need in order to eat. Facilitate a discussion on the parts of our body involved in this process, both internal and external, and how those structures are used. Create a list for the class to see.

Discussion questions:

• How did you decide the sandwich was something you wanted to eat? (Nose, eyes)
• How could you tell where the sandwich was? (Eyes)
• How did you get the sandwich up to your mouth? (Hands with opposable thumbs)
• How did you take a bite? (Teeth)
• How did you eat the sandwich? Did you swallow it whole? No, you probably had to process it and chew it up first. How did you do break it down into pieces that you could swallow? (Teeth, tongue, saliva)
• Why is it beneficial for us to eat sandwiches? (Eating food allows us to survive, gives our body energy, helps us grow)

Introduce that you are going to be thinking about the structures that other animals have on their body and how those structures help them survive. You may want to write a guiding question in a prominent place in the classroom: What structures do ladybugs have on their body to help them survive?

Part Two (30 minutes)

Show students this video: Ladybug Eating an Aphid: https://www.youtube.com/watch?v=jfL_5QWSrQ4.

Students should make observations about structures the ladybug is using to eat as they watch the video. Students should record observations in their science notebooks. Remind students that you are thinking about structures that animals have on and inside their bodies and thinking about how those structures help them survive. You may also need to clarify the difference between an observation and an inference if you have not yet covered it in class.

Once the video is finished, give students a few minutes to finish up writing and then have them talk to a partner next to them about what they observed.

Have students share out the sequence of events that they observed one at a time. As each student shares, compile a list of behaviors that students observed. These are the main points that you want to get across and the ideal sequence to end up with:

• The ladybug is standing on a leaf.
• It looks like the ladybug is “sniffing” around or looking for something at the very beginning.
• The ladybug is eating something.
• The ladybug looks like it is cleaning itself after it finishes eating.
• It looks like something is running up to and/or attacking the ladybug.
• The ladybug ducks down “like a turtle” to protect itself from the attack.
• The ladybug moves to the underside of the leaf to avoid whatever is attacking it.

As students share the sequence of events, ask them questions about the structures the ladybug is using in order to complete the action. You can prompt them by asking, “What part of its body is it using to do that?”

After you have finished developing the list of behaviors, ask students if they noticed any other structures on the ladybug that were not used or if there are any other structures they are curious about.

Part Three (Time is flexible – filling out worksheet and discussing will take about 30 minutes.)

Provide students with copies of books about ladybugs. Good titles include “Are You a Ladybug” by Judy Allen and Tudor Humphries, “A Ladybug’s Life” by John Himmelman, and “The Life Cycle of a Ladybug” by Colleen Sexton. In addition, “Ladybug at Orchard Avenue” by Kathleen Weidner Zoehfeld describes the Ant/Ladybug/Aphid interactions.

You can also show students videos of other beetles eating and avoiding attack while eating:

• Tiger Beetle Eating: https://www.youtube.com/watch?v=rae-R7v_ij8
• Ants Attacking a Ladybug While it Eats Aphids: https://www.youtube.com/watch?v=S8RTdznEFio

Through reading the texts and making observations of beetles in videos, students are gathering evidence of the structures that ladybugs have on their bodies and how those structures are used to help them grow, survive, and reproduce.

Watch the Ladybug Eating an Aphid video one final time: https://www.youtube.com/watch?v=jfL_5QWSrQ4. Students should fill out the “How does a Beetle Eat” worksheet. Students are making an argument based on the evidence in the texts and media. You can use their responses to this worksheet to assess learning.

Remind students that insect mouthparts help the insect grow and reproduce. What other body parts and behaviors does the ladybug use to help it survive?

Discussion points:

• Are ladybugs and tiger beetles predators or prey? How do you know? (Sharp mandibles)
• Can you think of other animals that are predators? How do their teeth look? (Wolf, shark, lion – they also have sharp teeth). We can conclude that sharp teeth are a structure that help predators survive since it is a pattern that we see sharp teeth on many animals that are predators.
• Remind students that not all animals have sharp teeth. Teeth can have different structures depending on what they help the animal eat. What does a cow’s tooth look like? Flat for grinding up grass. How do our teeth look?
• Similar to how other animals have different teeth depending on their function, insects do not all have the same type of mouthparts. Not all insects are predators with sharp teeth. Different types of insects eat different things to survive.

Part Four (1 hour): Mouthparts Design Challenge

Divide students into five teams. Have students sit with their team. Explain that each team is going to design mouthparts for a different type of insect. Each insect has a very specific diet. In order for an animal to grow, survive and reproduce, their mouthparts need to be well adapted to feed on their food source.

You may wish to write each food type on an index card and give each team their food card. You could also find examples to give to each team – e.g. a fake flower, a banana, an acorn.

Food Type	Teacher Notes	Real Life Example (For Teacher’s Information)
Seed that has a hard outside and a liquid center. The insect needs to be able to get to the liquid center.	This insect will have to be able to drill through the hard outside and suck or pump out the liquid inside.	Acorn Weevil
Nectar deep inside of a tall flower.	This will be the easiest design challenge.	Butterfly
Fruit that has to be turned into a liquid first.		House Fly
Blood	Remind students that in order to eat blood, the insect needs to be able to get to the blood so has to be able to pierce through skin.	Mosquito
This insect needs two different types of food to survive – a liquid and a crunchy solid.	This insect will need to have two different types of mouthparts.	Bee

 

 

 

Give students about 30 minutes to work with their team and design mouthparts. Have them fill out the Mouthparts Design Challenge Worksheet as they go. If you have materials like construction paper, tape, pipe cleaners, straws, etc., you could ask students to physically build a model of the mouthparts.

Once students are finished, have each group take turns sharing their design challenge and the mouthparts that they came up with.

Finish the lesson by showing images of real insect mouthparts and asking students to think about the function of those mouthparts. Why do they look the way they do? How does it help the insect survive?

        

Learning Assessment

Information provided on the student worksheets and in class discussions can be used to assess student learning. You could extend this lesson and further assess by assigning students to research different types of insects and their mouthparts and then create a poster in which students have to create a diagram of an insect and label the mouthparts and describe how those mouthparts help it eat.

References

Cunningham, A. P., J. R. Brandle, S. D. Danielson, and T. E. Hunt. 2007. Lady beetles of Nebraska. University of Nebraska-Lincoln Extension Publications: EC1780.

Johnson, N. F., and C.A. Triplehorn. 2005. Borror and DeLong’s Introduction to the Study of Insects. Belmont, CA: Thompson Brooks/Cole.