Triboniophorus graeffei (ATHORACOPHORIDAE) Red-triangle Slug


These are our largest slugs and vary in length between 70-140 mm. They are white to creamy white in colour and have a distinctive red triangle on the mantle and red edges on the foot. They have two tentacles and a breathing pore on the back. Slugs are hermaphrodites, having both female and male reproductive organs. Once slugs have located a mate, they encircle each other and sperm is exchanged through their protruded genitalia. A few days later the slugs lay around 30 eggs into a hole in the ground, or beneath the cover of an object such as a fallen log. They are quite common in the garden and an indicator of good quality habitat with plenty of moisture. Unlike naughty garden slugs, the Red-triangle is a beneficial native animal and is not a threat to your garden plants. It eats mostly algae. Some enterprising naturalists utilise Red-triangle slugs in their bathrooms to eat the mould that grows on bathroom walls.
Slugs mating. Photo: Anne Jones

Backyard Slugs

These two photos show the slugs on Tuckeroo trees in a backyard in The Gap, close to a water tank and the creek.
Photo: Dee

Photo: Dee

Arboreal Red-triangle Slug

During the big wet of January 2011 in Brisbane this Red Triangle Slug was spotted in the very top of a palm tree. It was about 5 metres above ground.

Arboreal Red Triangle. Photo: Robert Whyte