The Banana Slug: Reproductive Strategies

Banana Slug: Ariolimax Dolichophallus

• largest slugs in North America and the second largest slugs in the world.
• Usually grow 6 to 8 inches in length, but sometimes they can grow to 12 inches.
• Although they appear worm-like, the banana slug is a shell-less mollusk.
• Between aquatic and terrestrial; Two adaptations allow it to live on land:
• To avoiding drying out, it carries its aquatic environment through slime
• Without gills, the banana slug uses a fleshy compartment called the mantle as a primitive lung. (looks like hump/shoulder of slug)

Male or Female?

Neither! The banana slug is a hermaphrodite, meaning the organism has both male and female reproductive organs.

Since all slugs have both sexual organs, there is no prettier gender. Banana slugs are also polygamous meaning they do not have one particular partner but rather more than one.

Mating and

Courtship Rituals

References

• There is no particular migration. Banana slug mating can occur all round-year but most likely when the conditions are right. Such conditions are not being too cold or too dry.

The Banana Slug

• Two banana slugs start by biting one another and possibly taking small chunks of flesh. Similar to the snake mating ritual, slugs are also known to sometimes raise the front part of their body and slam down onto their partner.

http://www.birdsamore.com/critters/slugs.htm

http://www.arkinspace.com/2012/11/the-banana-slug-natures-giant-recycler.html

http://en.wikipedia.org/wiki/Banana_slug

http://www.welcomewildlife.com/?folder=pages/urban%20wildlife/other/snails

• The banana slug excretes slime containing pheromones that attract other slugs to mate.

Video Links

• The slugs complicated courtship dance probably makes sure that not only are the two slugs ready to breed but that they are the same species. During the dance two slugs will circle each other lunging at each other, nipping and hitting one another with their tails. Towards the end of the dance slugs may also display their sexual organs

Reproductive Strategies

Apophallation:

http://bio.research.ucsc.edu/grad/weaver/animations/penischewing.mov

Copullation

The two slugs then begin to mate by positioning their heads to one another in a ying-yang symbol. Their genital opening area is near the head.

Several hours later, averaging at 5, the pair is stimulated enough to internally fertilize one another by exchanging sperm.

Slug Species Behavior

Apophallation

When picking a mate, a slug should choose one that is relatively the same size.

Why? Because the banana slug’s penis is basically the length of its body. Occasionally, while mating, one slug could become stuck. The two slugs will spend several hours trying to impenetrate. If unsuccessfully, the two will engage in apophallation, which is the gnawing off of the stuck penis.

• Some species present different response behaviors when attacked, such as the Kerry slug. The Kerry slug retracts its head stays contracted in a ball-like shape
• Some slugs can self-amputate a

portion of their tail to help themselves

escape from a predator

• Some slug species hibernate

underground during the winter in

temperate climates, but in other species,

the adults die in the autumn.

Gestation & Offspring

• Banana slugs externally develop offspring by laying averagely 70 eggs which are laid in a log or on leaves.

• The parents provide no further care for their eggs beyond finding a suitable hiding spot. They abandon their young after birth.

• Gestation period is 3-8 weeks, and take only a few months after hatching for offspring to mature.