Friday, December 3, 2010

Creature Feature - the "good" snail

At some point or another, nearly every gardener has done battle with snails and slugs. What many don't know is that some snails are beneficial and actually eat the snails and slugs that do damage. In Florida, there are five species of predatory snails. The most common of these is the Rosy Predator Snail (Euglandina rosea). This is a fairly large snail, growing up to 2 ½ inches in length. It is easily identified by the glossy, elongated shell and the rosy or brownish-pink coloration.
Hot on the trail of the bad guy that ate that hole in the leaf!
The Rosy Predator Snail (also known as the Rosy Wolf Snail) is widespread in Florida, but is also found in Georgia, South Carolina, Alabama, Mississippi, Louisiana, and Southeastern Texas.

The snail lives for up to two years, and one study showed that a single individual can consume more than 350 damaging snails in its lifetime. The Rosy Predator follows the slime trails of its prey in order to find its next meal. Small snails are eaten whole and larger snails are eaten live, right in the shell. Here's an adult feeding on a bush snail.

When the predators reach sexual maturity they search out a mate. Snails are hermaphroditic so both partners of a successful mating will be pregnant.

Approximately thirty eggs are laid at a time in the soil and these hatch in about a month.

They immediately begin exploring their territory and looking for prey.

Here's a baby predator feeding on a bush snail.
Newborn rosy predators are usually pale, but the shells develop more coloration as the snail grows.
Young Rosy Predator
In 1955, Euglandina rosea was sent to Hawaii in an attempt to control the invasive Giant African Snail. The newest inhabitants reproduced quickly, and within three years 12,000 Rosy Predators were collected to send to other tropical regions, including New Guinea, Okinawa, and the Philippines. Like most attempts to introduce predatory species into a new environment, this one ended in disaster. The Rosy Predator preferred to feed on the colorful native Hawaiian tree snails, eventually eating several species to extinction.

In areas where the Rosy Predator snail is native, it is a very beneficial creature to have living in your landscape. Gardeners can often find empty shells of the destructive Bush Snail where the Rosy Predator has been feeding.
Gone but not forgotten!
Be on the lookout for this “good snail” and make it welcome in your garden!


Steve Asbell said...

A creature feature meme? What a great idea! I found one of these in my garden on the alocasias, and thankfully decided to take photos and let it be, since I don't like to kill pests in the garden anyways. The balcony is another story though... too little natural predators there.

NanaK said...

Wow, I didn't know that this was a "good" snail. I, fortunately, haven't had a snail problem and I guess that's why I don't see this one in my garden. I remember it from my childhood days though. I never realized it was eating all those little round ones. If I see one in my garden I will let it be. Perhaps it will eat some slugs. I do have a few of those. Thanks for the info.

Susan said...

I had one of those rosy critters in my garden just recently. I was surprised by its large size. I have way too many small snails that do lots of damage.

Andrea said...

Hi Jim, we don't have snail problems in our property but i see these snails in more wet and humid areas. Sometimes i see a bigger snail we call "Japanese snails" but i dont know the genus or species.

Stephanie Suesan Smith, Ph.D. said...

This is a fun meme. In North Central Texas, we don't have these snails. However, I wonder what happens to the predatory snails when someone puts out the iron based slug bait. Do they eat it? Or what if they eat a snail that has consumed it?

Stephanie Suesan Smith,Ph.D.

Unknown said...

I have been reading garden blogs for awhile now and I think I can safely say that snails are not a popular topic. Thanks for this post. It reminds me that I should look into the snails in my area a bit more too. I think they have changed a bit since I was a kid. There seems to be an invasive larger one among us not but I am simply not sure.

catharine Howard said...

Dear GJ now that is USEFUL!

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