Ariolimax buttoni is a species of banana slug native to the West Coast of the United States.[1] The species has a yellowish-tan hue that is similar to a banana and can be either spotted or unspotted. These slugs tend to be more sedentary but will migrate to find food or reproduce.[2]
A. buttoni are foragers that eat dead organic matter. Like most mollusks, these slugs have a mouth on the bottom of their head with a jaw that enables them to break off smaller bits of food. Inside their mouth, they have a tongue called a radula that is covered in microscopic teeth to help break down the food even further. Once the nutrients of the food have been broken down and absorbed, the slug excretes packaged waste through the anus located on the side of its head.
Like other banana slugs, A. buttoni has a single lung that aids in gas exchange. To aid in this process the slug has a pnuemostome, a small opening in the head that can close or open depending on the slug's oxygen and water levels.
Banana slugs are hermaphroditic, meaning they are both male and female at the same time.[3] During reproduction, Ariolimax buttoni engages in apophallation - the behavior in which a slug chews off its mating partner's penis.[4] Their mating season is very long, lasting from February to early September. In addition, the copulation itself is long. In a study conducted by Janet Leonard, data showed that on average the mating process would last up to seven hours with some extreme cases even taking 23. Since the slugs are hermaphroditic, one slug acting as the female would invert its penis for sexual reproduction to take place. However, cross-fertilization is not always necessary. A. buttoni can produce viable offspring with high rates of hatching success through uniparental reproduction.[5]
Ariolimax buttoni moves via a foot on their underside that contracts and relaxes. In addition, they can glide over surfaces by producing a slime layer that aids in combating friction.[6] They tend to be mainly sedentary but will move towards food and mates. Since the slugs have poor vision, they struggle to overcome physical barriers. However, the thick mucus coating on their skin enables them to stick to surfaces and move vertically over obstacles.
A. buttoni lives around 30 months. They tend to reach sexual maturity at about one year and lay eggs in the fall or winter. It has been observed that Ariolimax buttoni begins to copulate at as little as 8 months of life.
Ariolimax buttoni does not have shells to defend themselves and their bright color makes them an easy target for predators. However, the slime they produce deters predators from eating them. The mucus coating on their skin is toxic and causes numbing to the mouth of organisms that ingest it. In addition, the thick, sticky slime slows and traps predators from catching up to the slug.