Bess beetles: An Investigation on Decomposition

By Hillary Guzik

Target Audience

1st grade

Estimated Time for Lesson

(one class period is approximately 50 min)

6 class periods total over the course of 7 to 9 sessions


This is a two part lesson on Bess beetles, Odontotaenius disjunctus. In part one, students will explore the morphology of the Bess beetles through hands-on investigations. Students will handle, draw, and label parts, and observe behaviors. In part two, students will discover what wood the Bess beetles prefer. They will come up with their own testable hypothesis. Students will observe and calculate decomposition; this will allow students to explore the benefits of insects that are decomposers.

Background and Introduction to Study Insect

Insects occupy almost every inch of the earth and are considered to be one of the most successful creatures. Bess beetles, Odontotaenius disjunctus, are in the family Passalidae and order Coleoptera. There are over 500 species of Bess beetles (Bibs et. al, 2010). Bess beetles are a very important decomposer of many types of woods. They are considered to be very beneficial to the environment. They prefer the texture of mediumwood (wood able to flake off) to softwood (wood crumbles) and enjoy hard decaying woods such as oak and maple (Hadley, 2014; Palmer, 2014). They eat and live in galleries in the decomposing wood. Bess beetles, unlike termites, do not have symbiotic bacteria in their gut to help them digest the cellulose from the wood. Instead, after the wood has been chewed and digested by a Bess beetle, a dietary fungus will grow on the feces. The beetles fully digest the wood fibers by re-ingesting their own feces, which contain a microorganism that helps get the nutrients out of the wood (Ceja-Navarro et. al., 2014; Hadley, 2014). This makes them a very important in food webs by degrading cellulose, which includes both micro- and macroorganisms. They will feed their feces to their young because the young cannot digest the wood; this is a type of parental care.

Bess beetles tend to live in groups and are considered subsocial insects (Nardia et. al., 2006). They make many different sounds by rubbing their body parts together, which is called stridulation.


Bess Beetle. Photo credit: Herbert A. ‘Joe’ Pase III, Texas A&M Forest Service,

Adult Bess beetles have three body segments, six legs, and are typically large and black. They have two pairs of wings; the elytra, or outermost pair, is hard and covers the innermost wing, which is softer and pliable. Bess beetles have mandibles modified for chewing wood. They exhibit complete metamorphosis.

Bess beetles are really good for the classroom because they are slow, do not bite, and are low maintenance. They exhibit many biological functions that can be highlighted in class. To care for Bess beetles, provide them with damp soil, a hard wood, and an enclosed terrarium. The beetle should be misted every other day to keep the environment damp and humid. Bess beetles live in captivity for about one and a half years and are not known to reproduce in captivity (Staff, 2014).


Learning Objectives

  • Student engaged and demonstrates skills in listening, discussing, and collaborating with a group.
  • Student records observations of bess beetles morphological structure. Identify different structures of the bess beetle and how it is relevant to habitat.
  • Students records observations of bess beetles behavior. Identify how sounds are produced by the bess beetle. Identify if bess beetles prefer to be social or alone.
  • Student records observations and identify bess beetles feeding preference.
  • Student will demonstrate ability to graph and present data.
  • Student will demonstrate ability to discuss the importance of decomposition by bess beetles.

National Science Standards:

1-LS1-1 From Molecules to Organisms: Structures and Processes

Structure and Function

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

Science and Engineering Practices

  • Planning and carrying out investigations to answer questions


Teacher Lesson Plan Instructions

Important Concepts:

Insect morphology

Importance of insect food preference

Importance of decomposition

Graphing/ presenting data

Group collaboration



Part 1: Exploring the Morphology of the Bess beetle (per group)

Bess beetle. They can be purchased at Berkshire Biological company. (–12.html).

Clear plastic cup or container – about the size of small critter container

Hand magnifying glass.

Bess beetle Notebook.

Colored pencils.

Part 2: Experiment with Eating Preference (per group)

8 to 10 Bess beetles. A kit can be purchased through Carolina Biological Company. (


Two or three kinds of wood (at least one oak or maple) around 9 oz each. Wood should be of a known species, do not use Pine or Cedar as this will kill the beetles (Palmer, 2014). The 9oz wood should be cut in half, then tied back together with twine. This will allow students to untie the twine and observe the galleries made by the Bess beetles. Wood can be bought locally where camping wood is sold, this is typically labeled with the type of wood it is. It can also be found in your local woodland area, but make sure to properly identify the wood so as not to harm the beetles.




(Plant/Vegetation Information, 2014)

Spray bottle filled with non-chlorinated water. This can be shared between groups.

Poster board.

Other poster making material.

Bess Bettle Notebook ( see end of lesson)



Part 1: Exploring the Morphology of the Bess beetle (1 class period)

  1. Introduce the Bess beetles to the class by watching the video “The Daily Antenna: Bess beetles” By The Bug Chicks. (ADDVIEDOHERE) (Reddick et. al. 2014)
  2. Conduct an open discussion to find out what students know and want to know about the Bess beetles.
  3. Divide students into groups (3-4 students).
  4.  Students will select one bess beetle and place it in the clear cup.
  5. Instruct groups to explore the morphology of the Bess beetle with the hand magnifying glass for 10-15 minutes. Encourage group discussion by prompting questions such as where are the eyes? Or how many legs does it have? Describe the texture of the beetle’s exoskeleton and how it moves, etc.
  6. Record morphological and behavioral observations in their Bess beetle notebook and return the Bess beetle to its terrarium.
  7. Have class share their observations findings from the observations.
    1. What did you see in your observations?
    2. What do you think is going on?
    3. What more can we find?

Part 2: Experiment with Eating Preference (5 total class periods)

Part A: Setting up experiment (1 class period)

  1. Divide students into groups (3-4 students each).
  2. Have students develop their hypothesis to test based on food preference (wood choice) of bess beetles. Remind students to have one testable variable to investigate.
  3. Instruct groups to pick chose a smaller terrarium with Bess beetles in it.
  4. Have students count the total amount of Bess beetles in the terrarium.
  5. Have groups pick out two kinds of wood. The wood should be clearly identified for the student or the students can use the chart in their Bess beetle Notebook to identify the wood themselves.
  6. Have students label and weigh each piece of wood. Then record the data on the worksheet provided in the Bess beetle Notebooks. Be sure your students know that they will be recording the weight of the wood for their data and the number of beetles on/and around each wood type when making their observations.
  7. Have students place the two pieces of wood into the terrarium with the Bess beetles. Mist it with the spray bottle of water. Observe Bess beetles’ behavior toward the wood.

Part B: Observations. Repeat these steps approximately every 3 days for 3 weeks; 6 days total. (½ class period)

  1. Gather students back into original groups.
  2. Have students pull out each sample, count the number of beetles on/in the wood, record the weight of the wood, and mist.

Part C: Data Analysis and Presentations (1 class period)

  1. Allow students time to compile and graph data in visual form on a poster or large piece of paper. Alternatively, the class can enter their data on a shared group chart to sum results.
  2. Have students present their data to the class and discuss other observations about the experiment and behavior of the beetles that they noticed. Discuss if the data provided evidence to accept or reject their initial hypothesis (prediction)?

Discussion Questions:

Did the Bess beetles prefer one wood type over another?

What factors may have affected the results?

How would you design the experiment differently if you conducted it again and why?

What did you discover about the morphological of the Bess beetle?

What did you discover about the behavior of the Bess beetle?

What is the importance of the Bess beetle to the environment?


All worksheets used to help guide the students through the activities are included in the Bess beetle Notebook


Assessment Standards for Students

Student Name:

Class Participation: (25 possible points)


Room for Improvement.

1pt score example

Good Work!

3pt score example


5pt score example

Points Awarded

Topic Engagement

questions or problems are generated by teacher student seems withdrawn from lesson

student generates questions or problems and are somewhat engaged

student properly generate questions and problems and are fully engaged

Listening and Question

student not able to listen or ask questions to complete lesson

student able to listen to most instructions or/and ask some questions

student activity listens and asks questions

Group Work Ethic

student does not contribute much information, ideas, or concepts to the group and does not participate in lesson activities

student able to contribute information, ideas, or concepts to the group and participate in lesson activities

student able to contribute information, ideas, and advanced concepts to the group and actively participate activities

Present Poster

student did not present a poster

student presented poster poorly

student presented poster well

Use of Time In Class

student did not use class time to its fullest potential

students had some down time that could have been used better during lesson

student used all class time properly and stayed on track during the lesson

Bess beetle Journal: (35 possible points)


Room for Improvement.

1pt score example

Good Work!

3pt score example


5pt score example

Points Awarded


some pages filled out

most pages filled out

all pages filled out

Behavior Recording

eligible recording of behaviors not cohesive thought

cohesive, semi- structures thought or less than three sentences

cohesive, structures thought and more than three sentences


insect only sketch not labeled or colored in

sketch missing sketch or color or labels

insect sketch, colored and labeled properly l



1-2 question answered correctly

3-4 question answered correctly

5-6 question answered correctly

Weight Measurements recorded

eligible data or missing more than two conditions or two days

most conditions recorded, most days recorded, mostly legible

data was accurately recorded and legible for all days

Conditions Graphed

graph not finished, and all conditions line color is not unique or key missing

graph missing one condition, or line color is not unique or key is missing

graph is clearly labeled with each condition having its own color and key is present

Testable Hypothesis

missing or not testable

too many variables


Final Poster: (40 possible points)


Room for Improvement.

1pt score example

Good Work!

3pt score example


5pt score example

Points Awarded

Legibly and Accuracy

legible and not accurate

legible somewhat accurate

both legible and accurate

Hypothesis Statement

missing or not testable

too many variables


Materials and Procedure

missing or only a part

only some listed

all listed and accurate


missing or only a part

only some listed

all listed and accurate

Results and Graph

missing or only a part

results or graph missing

both results and graph present


missing or answer does not include all parts of the question

offers simple answer and includes most parts of the question

explains answer and includes all parts of the question


did not discuss the importance

discussed the importance but did not understand

understood and conveyed importance

Concepts as a Cohesive Whole

student lacks general understanding of concepts and ideas, and/or is not able to related them to other concepts and ideas in most questions

student understands general concepts and is able to relate them to other concepts and ideas in most questions

student understands concepts and is able to relate them to other concepts and ideas in all questions









Bibbs Christopher S, Hodges Amanda C, Baldwin Rebecca W. “Horned Passalus – Odontotaenius Disjunctus (Illiger).” Featured Creatures. University of Florida, Dec. 2010. Web. 03 Dec. 2014.

Ceja-Navarro JA, Nguyen NH, Karaoz U, Gross SR, Herman DJ, Andersen GL, Bruns TD, Pett-Ridge J, Blackwell M, Brodie EL.Compartmentalized microbial composition, oxygen gradients and nitrogen fixation in the gut of Odontotaenius disjunctus. 2014. ISME Journal. 8(1):6.

Hadley Debbie. “A Guide to Caring for Bess beetles.” About Education. 2014. Web. 03 Dec. 2014.

Nardia James B, Beeb Charles M, Millerc Lou-Ann, Nguyend Nhu H, Suhd Sung-Oui, Blackwelld Meredith. Communities of microbes that inhabit the changing hindgut landscape of a subsocial beetle. 2006. Arthropod Structure & Development. 35(1):57.

Palmer, Tony. “Question about Bess Beetles.” Message to the author. 02 Dec. 2014. E-mail.

“Plant/Vegetation Information” Outdoor Info. Snyder’s Marina. 22 April 2014. Web. 03 Dec. 2014.

Reddick Kristie, Honaker Jessica. “The Daily Antenna: Bess beetles.” The Bug Chicks & Solpugid Productions. 2014. Web 03 Dec. 2014.

Staff. “Carolina Arthropods Manual.” Carolina Biological Supply Company. 2014. p8-9. Web. 03 Dec. 2014.

Insert workbook handout here


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Entomology Lesson Plans for Elementary Educators Copyright © by University of Nebraska—Lincoln is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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