Friday, August 6, 2021

Leopard Slug


This story is from Alee Huerta who has returned to the MN fold after an absence while pursuing her education.

This past weekend we had a Leopard Slug crawl across our porch. My 1st thought was to grab the salt... and I did.  But as my 7 year old buddy and I plopped down with the salt, my inner Naturalist was like.... "hold up."  I'm glad I took the time for education because I found out that these slugs don't actually destroy living plants, a common misconception.  Leopard Slugs (Limax maximus) eat fungi, rotting plants and even other slugs. They need to keep their bodies damp in order to breathe, so are usually found in dark, damp places, particularly among rotting logs.
Sex on a string -Bairds


All slugs are hermaphrodites, meaning that each slug has both male and female sexual organs. They still need to mate with another individual though and LS have quite a spectacular way of doing this. The two slugs climb a tree or other structure, then produce a thick strand of mucus that they hang from on a branch.  This is partially because their penis which will exchange their sperm is so large that it requires gravity to distend it, actually causing their body to shrivel up some from loss of fluid. intertwined with one another.   These sex organs protrude from their heads and intertwine to exchange sperm, the pink packet on the left.  You can see all the action as filmed here by our MN, Michael Baird.   

As we say in the WOLF School, "here is another fun fact."  Once they have completed copulation, one or both will eat their way up the mucus strand, retrieving the energy stored in it. This and other fun facts are more colorfully described in this story from Wired.

Editor's note:  This is a family blog but we will recommend this graphic BBC video as it is narrated by the very proper Richard Attenborough.

After mating, each slug lays clutches of transparent, round eggs in damp places.  As slug babies, they are a primary food source for lightning bugs! I love lightning bugs, so the way I see it, to love any one certain thing you need to respect everything that one certain thing needs.  They reach sexual maturity in 2 years and can live for 3 years.


Limax maximus, literally biggest slug, originally were native to Europe and Mediterranean countries of Africa and were first found in Philadelphia in 1867.  In spite of their top speed of 6" per minute they really get around and are now found around the globe! They are almost always found near human habitation — usually in lawns, gardens, cellars, outbuildings or in other damp areas.

LS is generally a nocturnal slug that feeds mostly on rotting plant matter and fungi as well as other slugs. In Texas and Oregon it can sometimes be a pest of gardens, greenhouses, cellars, and mushroom beds.  On the other hand, by eating dead and rotting plants, as well as fungi, Leopard Slugs recycle nutrients and fertilize the soil.
 
Our LS like many other slug species have a small disc of shell inside their body. Slugs evolved from snails and this disc is a remnant of what used to be the snail’s shell.  They can come in a wide range of shades although these leopards never change their spots.

Finally, research by Christie Sahley and colleagues have demonstrated associative learning in LS by aversion therapy.  Carrot and potato juice normally attracts them.  After they have been exposed to them flavored with an additional bitter dose of quinine sulfate, these attractants subsequently lose their gustatory charm.  Yes, it appears you can teach old slugs new tricks.
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Dr. Chris Barnhart and MDC have published Land Snails and Slugs of Missouri, available in many different formats at this Archive link.  You can download it as a PDF or Kindle document.