Lab 1 – Prelab instructions

Note: Prelabs are due at the beginning of lab. I will check briefly to make sure you have all the correct sections written. Later in the quarter, you will turn in your lab notebook and I will check them in more detail for additional points.

Over the course of the quarter, we will be doing lab experiments and a group project using the bean beetle Callosobruchus maculatus as our study organism. In this first lab, we will use compound and dissecting microscopes to observe and draw bean beetles and their sensory structures.


  • Familiarize yourself with microscope technique (compound and dissecting microscopes)
  • Familiarize yourself with our study organism, the bean beetle Callosobruchus maculatus
  • Observe characteristics of male and female bean beetles and their sensory structures

Before lab:

  • Read “How to do a lab notebook” and write the title, purpose, background, and materials and methods for this first experiment in your lab notebook.
  • Your title and purpose should be based on the information above.

Background section should include:

  • Diagrams or drawings of a compound light microscope and a dissecting (also called stereo) microscope (cite sources!)
  • Information about when each type of microscope should be used vs. the other type
  • Descriptions of basic beetle anatomical structures, especially sensory structures. Focus on external anatomy, not internal.
  • How to tell male and female bean beetles apart

Materials and Methods should include:

  • Steps for making a wet mount slide and viewing it under a compound light microscope at high magnification
  • Steps for viewing a specimen under a dissecting microscope (also called a stereo microscope)

Here are some sources you may find helpful when researching this information:

Compound light microscope video:

Dissecting microscope video:


Virtual beetle dissection. If you click “Inspect” it will show you the name and function of any part you hover over.

Identifying the sexes of bean beetles