Food Preferences of Slugs

A CIBT Lab Exercise in Ecology and Evolution



Students will investigate the food preferences of garden slugs (Arion subfuscus) using simple equipment including margarine tubs, graph paper, scissors, and common plants, both wild and cultivated. The exercise is genuine scientific research in that: a) the student devises his/her own "research question" about slug feeding behavior, and b) the results are truly unknown to the student-experimenter and possibly to the instructor) prior to the experiment. In carrying out the complete set of experiments described below, students learn that one way to achieve precision and accuracy is by designing experiments with many replicates. The following laboratory write-ups are included:

  • Slugs and the Scientific Method: This exercise uses slugs to teach the difference between “observation” and “opinion” and introduces the concepts of “controls” and “hypothesis testing.”
  • The Vermiculturist’s Experiment: This paper exercise illustrates the importance of controls, variables, and replicates in experimental design.
  • Food Preferences of Slugs: Students design and carry out their own experiment to test a slug’s preference between two or more food sources.
  • Food Preferences of Slugs (continued): Students will also benefit from the opportunity to further practice their experimental design skills by looking more closely at the complex question of “How do you determine what a slug really likes?”

Appropriate Levels

Life Science, High School, Honors, and Advanced Placement Biology.


Time Required

Approximately five 45-minute lab periods of in class time are necessary to carry out all parts of the lab. Minimal teacher preparation time required.



Slugs and the Scientific Method:

  • Slugs (at least one per team of students)
  • plastic container with lid to serve as "slug home"
  • slug food such as lettuce, other leafy plant material, and fruits
  • large petri dish to place slug into while making observations
  • metric ruler
  • hand lens
  • dissecting microscope (optional)

The Vermiculturist’s Experiment:

  • No additional materials required

Food Preferences of Slugs:

  • slugs - allow at least 2 per team of students (any species of slug or land snail will do)
  • plastic container to serve as "slug home"
  • slug food such as lettuce, other leafy plant material, and fruits
  • mm graph grids photocopied onto transparency film
  • metric ruler
  • scissors
Copyright for this material is held by Cornell University, the Cornell Institute for Biology Teachers (CIBT), the Center for Nanoscale Systems Institute for Physics Teachers (CIPT), and or West Hill Biological Resources, Inc., 2014. This work may be copied by the original recipient from this web site to provide copies for users working under the direct supervision of the original recipient. All other redistribution of this content without the express written permission of the copyright holder(s) is prohibited.

Price:       No Charge


Diane Emord, Henninger High School, Syracuse, NY

Lindsay Goodloe, Learning Skills Center, Cornell University, Ithaca, NY

Mary Colvard, Cobleskill-Richmondville High School, Cobleskill, NY 

Dan Flerlage, Alternative Community School, Ithaca, NY 14850 (created the "Vermiculturist’s Experiment)