Banana Slug

Habitat and Eating:

Banana Slugs can be found on the west coast of North America, specifically the Pacific Northwest. They are some the largest terrestrial gastropods and can grow up to 8 inches (Gervais, 1997). Banana slugs eat a variety of things including animal waste, leaves, moss and fungi, and other types of detritus. In more northern areas, like Washington, it was reported that banana slugs were active from April to November and then disappeared to hibernate; however, in warmer areas in central California, they were active throughout the year (Pearson, 2006). This shows that there may be tendencies to hibernate depending on their location. Because of the adhesive mucus they secrete,they are also capable of reaching fruit of many plants. Because Banana Slugs sometimes eat fruit seeds, they can also potentially help aid forest plant regeneration. A study was done in 1997, to see if banana slugs were capable of dispersing viable seeds after defecation. Gervais, Traveset, and Willson collected fruit seeds from salmonberry, blackberry, evergreen huckleberry, red huckleberry, and large flower fairy bells, that banana slugs passed and then planted them to test their hypothesis. Seeds of all the plant species that were tested had successfully germinated even after slug ingestion and passage, except for the salmonberry. These slugs could've been described as benign, but could they even be helpful? These slugs can disperse seeds through two ways: primary dispersal and secondary dispersal. Primary dispersal happens when directly ingesting seeds from the mother plant. Secondary dispersal happens when they remove seeds that were already detached from the mother plant. An example of this is when they eat other animal waste. Their aid in seed dispersal may be helpful, but is it a major contribution? Slugs have something working against them when it comes to seed dispersal: they do not cover significant distances in day to day movement, and especially in the time it takes for seeds to pass through their digestive tracts (Gervais, 1997). It is still unclear as to how influential their seed dispersal truly is.

Locomotion/Slime:

Mollusks only have one foot used for locomotion. This can limit the movement of slugs only those compatible with the structure. Not only do they get around using one foot, they can also adhere to the surface they are moving on using mucus. This mucus is secreted and coats the foot of slugs. It essentially acts as glue, so that slugs can stick to surfaces during locomotion. This is very different from aquatic gastropods that use cilia for locomotion. It has been hypothesized that cilia locomotion is the primitive form of movement in gastropods, but it has not been proved. Mollusks move by different types of pedal waves on their foot, and slugs can even move the anterior part of their body at a different speed than the posterior. (Denny, 1981) The mucus is not only used for adhesion, but it also is used for hydration. Slugs, unlike shell-less snails, are especially prone to water gain and water loss, to physical damage from the environment, predation, and parasites. When chemically or physically stimulated, these slugs can flood the skin surface, from the mantle or foot, to remove or neutralize toxins. It also serves to moisten the skin and correct hyperhydration (Martin, 1985). The mucus is also used as a defense from predators. It contains an anesthetic that numbs the mouth of predators trying to eat them, making it impossible to chew (arkinspace.com).