Slug Garden Party

June 2009

Univited Guests

Why are these slugs on my table? Are they a pest?


Karen Haggitt from Northgate phoned the Inquiry Centre about large slugs that were grazing on her garden table one wet afternoon. These are Red-triangle Slugs, Triboniophorus graeffei. These large (70mm) native slugs are common in the Brisbane region but seldom seen as they are usually nocturnal and secretive.

They are easily recognised by the red triangle surrounding the breathing pore on their backs.

Red-triangle slug feeding tracks Golden and bright red forms of the Red-triangle Slug from the Border Ranges region Snug slug shelter

They are not pests. Unlike the many species of introduced exotic slugs that eat plants, Red-triangle Slugs feed on the algae and lichen attached to tree-trunks, rocks, garden furniture and concrete paths.

Usually the only evidence of their presence is the feeding tracks they leave behind (see picture kindly supplied by John of Ocean View). Overcast rainy days and the luxurious growth of algae and lichen have brought them out of their hiding places in many areas of Brisbane.

In some areas these slugs may be bright pink, red, gold or orange. Scientists have yet to determine whether these are simply colour forms or separate species.

Queensland Museum's Find out about... is proudly supported by the Thyne Reid Foundation and the Tim Fairfax Family Foundation.