Abstract
If you have a garden, you probably know about snails (or their shell-less relatives, slugs). You may even be looking for a good way to keep them from getting into your garden and eating up the results of all your hard work. Here's a scientific look at one method of discouraging this garden pest.
Objective
This project has two goals:
- to determine if snails are attracted to or repelled by certain substances;
- if repellent substances can be identified, can they protect citrus trees (or garden plots) from snails and the damage they cause?
Introduction
The common garden snail is a nuisance to home gardeners, and can be the cause of major damage in citrus groves (UC IPM, 2005). Snail and slug poisons are available, but perhaps there are methods for protecting gardens and crops from snails that are more environmentally friendly? Are there substances that can work as effective snail repellents to protect citrus trees from snails? Would these substances work for garden plots as well?
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| Figure 1. This copper banding sure seems to be creating a snail traffic jam! Will it work for you? |
The University of California's Integrated Pest Management webpage (UC IPM, 2005) suggests using copper banding to deter snails. As shown above, it seems to be an effective method. Can you think of other substances that might work as a "keep out" sign for snails? Do other metals work? Since snails glide along on a secretion of mucus, would rough surfaces work to deter their progress?
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:
- snail anatomy:
- attractant,
- repellant.
Questions
- How do snails move?
- What do snails eat?
- What is the preferred habitat of the garden snail?
Bibliography
- This page has detailed pictures of the external and internal anatomoy of the garden snail:
Herreid, C., 1999. "Snail Helix aspersa," Evolutionary Biology Class website, Department of Biological Sciences, State University of New York, Buffalo [accessed August 16, 2006] http://wwwbio200.nsm.buffalo.edu/labs/tutor/Snail/.
- These pages have information on snails and methods for managing these garden pests:
- UC IPM, 2005. "UC Management Guidelines for Brown Garden Snail on Citrus," Statewide Integrated Pest Management Program, Agriculture and Natural Resources, University of California [accessed August 4, 2006] http://www.ipm.ucdavis.edu/PMG/r107500111.html.
- Dekle, G.W. and T.R. Fasulo, 2002. "Brown Garden Snail—Helix aspersa Müller," Florida Department of Agriculture and Consumer Services, Division of Plant Industry and University of Florida [accessed August 4, 2006] http://creatures.ifas.ufl.edu/misc/gastro/brown_garden_snail.htm.
Materials and Equipment
To do this experiment you will need the following materials and equipment:
- garden snails;
- large plastic box;
- plant pots;
- potential snail attractants: lettuce, apple slices, orange slices, etc.;
- potential snail repellents (check your local hardware store): copper foil or sheet metal, aluminum foil or sheet metal, sandpaper, etc. (Note: do not use sugar, salt, laundry detergent, slug bait, or other substances known to kill snails.)
Experimental Procedure
- There are many possible ways to test substances to see whether they repel snails. With any of these methods, you will need to perform repeated trials to make sure that your results are consistent. Choose one of the following methods (or try several of them to see which works best for you):
- place the substance directly in the path of a moving snail and observe whether or not the snail changes direction when it encounters the substance;
- cover the bottom of a plastic box with different substances, and release one or more snails into the box; use time-lapse photography to determine how much time snails spend over each substance;
- place the substance in a ring around one or more snails and observe the behavior of the snail(s).
- To test attractant substances, try the following procedure:
- Put several inverted clay pots in a plastic box.
- Place samples of the substances to be tested on top of the pots.
- Leave at least one pot empty.
- Release snails into the box and observe their behavior.
- You may need to moisten the test area with a spray bottle of water to encourage the snails to explore.
- Count the proportion of snails on each pot.
- Conduct multiple trials and average the results.
- To test the relative effectiveness of different snail repellents, try the following procedure for each substance to be tested:
- Put a single inverted clay pot in a plastic box.
- Half-way up the pot, wrap (or coat) the pot with the repellent substance to be tested.
- On top the pot, place a sample of the most attractive substance identified in the previous step.
- Release snails into the box and observe their behavior.
- You may need to moisten the test area with a spray bottle of water to encourage the snails to explore.
- How many snails attempt to approach the bait? How many succeed in crossing the repellent substance being tested?
- Conduct multiple trials and average the results.
Variations
- Test the effectiveness of other metals (e.g., aluminum foil) for protecting citrus trees from snails. Can you measure a voltage between the snail's foot and copper sheet metal? Between the snail and other metals?
- Does copper banding remain effective even after it has been exposed to the weather and become oxidized? For speeding up the process of weathering the copper, soak it with vinegar overnight.
- How fast do snails move? How is a snail's speed affected by variables such as surface texture, moisture, temperature? (Remember to design your experiment so that you test a single variable at a time.) For the most reliable results, it is best to make measurements using many individual snails, using repeated trials for each individual.
- For many garden plants, wrapping the stem in copper is impractical. Is it possible to protect an entire garden? Does a border made of copper sheet metal keep snails out of a garden plot? Compare side-by-side beds using different border materials, and take a regular "snail census" to find out.
Credits
Andrew Olson, Ph.D., Science Buddies
Sources
This project is based on:
Last edit date: 2006-08-15 22:30:00
Career Focus
If you like this project, you might enjoy exploring careers in
Zoology.
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Zoologist and Wildlife Biologist
Ever wondered what wild animals do all day, where a certain species lives, or how to make sure a species doesn't go extinct? Zoologists and wildlife biologists tackle all these questions. They study the behaviors and habitats of wild animals, while also working to maintain healthy populations, both in the wild and in captivity. | |
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