An urban myth abounds that land snails are so strongly led by their sense of smell that when they scent beer, they risk their lives following its trail. In fact, a common way gardeners clear land snails from their gardens is with beer — “Snails love beer. Inexorably they are drawn to it. They sidle up to the pots of beer, get drunk, fall in and drown” (Phillips). This fatal olfactory attraction of snails’ has also been borne out academically. A 2008 experiment comparing the effectiveness of different bait traps on Achatina fulica ranked beer third out of five baits (Vanitha, Karuppuchamy, and Sivasubramanian, 2008). Furthermore, its also interesting to know that the brand of beer also makes a difference. “We once bought the cheapest beer we could and succeeded in catching exactly one slug with the six-pack. An entomologist at Colorado State University, Whitney Cranshaw, conducted a beer tasting for slugs in 1987, killing 4,000 of them in eight weeks in the name of scientific inquiry. Kingsbury Malt Beverage attracted the most, but Michelob and Budwieser fared well too.” (Klein and Wenner)
But its not actually the alcohol but the yeast present in the beer is what attracts the varmints. The alcohol just befuddles them and makes it harder for them climb out of the jar trap containing the beer. In fact, to probe this, my group had carried out an experiment using structures like Y Chamber which look something like this:-
We identified the different components of beer, i.e. ethanol, water, yeast and sugar. Later, we introduced yeast in one arm of the Y chamber and water, ethanol and sugar in the other arm one at a time. What we observed was that the snails would always start moving towards the yeast and not be attracted at all by the contents of the other arm.
Thus, even though the urban myth proclaims that snails are drunkards and are attracted to beer, it should be known that snails really are harmless sober creatures with an innocuous attraction to yeast
Phillips, Sara. “Getting Rid of Snails.” G Magazine. G-Online, 4 Jul. 2008. Web. 12 Feb. 2010.
Vanitha K., Karuppuchamy P., and Sivasubramanian P. (2008). “Comparative effectiveness of bait traps against the giant African snail, Achatina fulica attacking vanilla.” Annals of Plant Protection Sciences, 16 (1), 221- 222.
Hilary Dole Klein and Adrian M. Wenner. “Environmentally healthy ways to trap and kill the pests in your house and garden”. University of California Press. Retrieved from http://www.ucpress.edu/books/pages/8778/snails.php. Accessed on 1st April 2010.