gray field slug

(Deroceras reticulatum)

Conservation Status
gray field slug
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNA - Not applicable

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Gray field slug, also known as milky slug, is a common, exotic, terrestrial, smooth land slug.

It is native to northern Europe, North Africa, and the Atlantic islands. It was introduced into North America and now occurs across the continent. It is most common in southern Canada and northern United States. It can be a serious crop pest, but is not listed as invasive nationally or in Minnesota. It is usually found above ground but under stones or leaf litter in open areas, especially cultivated areas.

The adult is stout, 1 to 2 long and slender when stretched out, short and bell-shaped when contracted. It has no visible external shell. The skin is thick and is covered with raised areas (tubercles) and grooves, giving it a granular appearance. The tubercles may be white, cream, gray, or tan. The grooves are more or less covered with darker brown or gray flecks. The saddle-shaped covering on the front of the body (mantle) is short but usually covers more than one third of the body. The breathing pore (pneumostome) is on the right hand side of the rear quarter of the mantle. It is difficult or impossible to see if not open. When open, it has a raised, pale border. Concentric wrinkles on the mantle form a fingerprint-like pattern. The pattern is off-center, centered on the pneumostome. There is a short, longitudinal ridge (keel) at the end of the tail. The underside of the foot (sole) has three distinct longitudinal regions. The central region is gray, the lateral regions are whitish to grayish-yellow. The mucus is clear but can become white when the slug is disturbed.

 
     
 

Size

 
 

Total Length: 1 to 2

 
     
 

Similar Species

 
 

This is the only Deroceras species that can change its mucus from clear to white.

Marsh slug (Deroceras laeve) is smaller, no more than 1 in length, and darker, smoky bluish-black.

Some other Deroceras species are identical in appearance and can only be distinguished when dissected by the male genitalia. However, they do not occur in Minnesota.

 
     
 
Habitat
 
 

Agricultural fields, parks, gardens, roadsides, and other open, cultivated areas

 
     
 
Biology
 
 

Season

 
 

Probably two generations per year

 
     
 

Behavior

 
 

Gray field slug is active at night. During the day it remains concealed in the ground. It does not burrow but uses existing crevices and worm holes. At night, it climbs onto vegetation to feed.

When at rest, the body is contracted and the tentacles are retracted. When disturbed, it exudes white mucus over its entire body, leading to one of its common names, milky slug.

 
     
 

Life Cycle

 
 

Eggs and/or hatchlings overwinter in soil. Adults die in the fall.

Sources disagree about the life cycle of gray field slug. Some sources say that adults overwinter. Others say the mostly eggs, sometimes juveniles, overwinter. Still others that hatchlings overwinter and adults die in the fall.

 
     
 

Food

 
 

Fresh leaves, fruits, and seedlings

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 29, 30.

 
  1/20/2021      
         
 

Nativity

 
 

Native to Europe and North Africa. Introduced.

 
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
  Class Gastropoda (gastropods)  
  Subclass Heterobranchia (heterobranch gastropods)  
  Infraclass Euthyneura (euthyneuran gastropods)  
  Subterclass Tectipleura  
  Superorder Eupulmonata  
  Order Stylommatophora (common land snails and slugs)  
 

Suborder

Helicina (helicinan snails and slugs)  
  Infraorder Limacoidei  
 

Superfamily

Limacoidea  
 

Family

Agriolimacidae  
  Subfamily Agriolimacinae  
 

Genus

Deroceras (smooth land slugs)  
       
 

Synonyms

 
 

Agriolimax agrestis

 
       
 

Common Names

 
 

field slug

gray field slug

gray fieldslug

grey field slug

milky slug

 
       

 

 

 

 

 

Glossary

Mantle

On gastropods: the fleshy, membranous covering of the front of the body.

 

Tubercle

On plants and animals: a small, rounded, raised projection on the surface. On slugs: raised areas of skin between grooves covering the body.

 
 
Visitor Photos
 
           
 

Share your photo of this gastropod.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach one or more photos and, if you like, a caption.
 
 

Alfredo Colon

 
    gray field slug   gray field slug  
           
    gray field slug      
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           
           

 

Camera

     
 
Slideshows
 
Deroceras reticulatum
Lloyd Davies
  Deroceras reticulatum  
 
About

Deroceras reticulatum

 
     

 

slideshow

       
 
Visitor Videos
 
       
 

Share your video of this gastropod.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach a video, a YouTube link, or a cloud storage link.
 
 

 

 
     
     
       
       
       
 
Other Videos
 
  Grey field slug (Deroceras reticulatum) - 2015-05-18
Westdelta
 
   
 
About

Published on May 19, 2015

Deroceras reticulatum, common names the 'grey field slug' and 'grey garden slug', is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Agriolimacidae.

De gevlekte akkerslak (Deroceras reticulatum) is een landnaaktslak uit de familie akkerslakken. Er zijn verschillende namen voor deze soort, zoals grauwe veldslak, grauwe aardslak, akkeraardslak en melkslak(je).

Geo location: 52.05226 4.24792

 
  Deroceras reticulatum (Müller, 1774) Gray Fieldslug
Chin Frank
 
   
 
About

Published on Feb 8, 2015

Downhill side of NC-105; under cinder blocks on shaded back lawn of small frame office building, Foscoe, Watauga County, North Carolina.The slug measured about 45 mm. in length.Also see: http://www.jaxshells.org/ret29b.htm and http://www.jaxshells.org/norw22a.htm

 
  Deroceras reticulatum - Grey Garden Slug Mating - Foreplay Ritual and Climax
Lisa Marie Carrick
 
   
 
About

Published on Sep 27, 2018

Here’s some video that I took a couple of years ago of a couple of grey garden slugs (Deroceras reticulatum) slugs mating. This is the sped up version.

The courting phase can take several hours, but luckily I usually seem to come across the couples near the end of their courting (about an hour before copulation). During courting, they trail each other in a circle - swinging their tails (this is mostly during the beginning of courtship and during precourtship), "kissing"/biting, and touching and stroking each other with their penises. Over the hours of courtship, they begin by circling quickly and slow down over time until just before copulation. During copulation. Sperm is transferred externally between both slugs. My favourite part is during copulation is when they "climax" and it looks like their penises explode, and what I believe is increased blood flow can be seen down the back of the head of the snails.

For more videos like this, follow me on IG at @garbage.nobility and/or check my personal arthropod related tag #garbagearthropodsetc to see all of my arthropod related posts in one place.

 
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this gastropod.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
  Alfredo Colon
8/14/2019

Location: Woodbury, Minnesota

gray field slug  
  Alfredo Colon
8/4/2019

Location: Woodbury, Minnesota

gray field slug  
  Alfredo Colon
6/17/2018

Location: Woodbury, Minnesota

gray field slug  
           
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

Binoculars


Created: 1/16/2019

Last Updated:

About Us | Privacy Policy | Contact Us | © 2021 MinnesotaSeasons.com. All rights reserved.