Black-and-gold Sapsucking Slug

Overview

The Black-and-gold Sapsucking Slug is a striking sacoglossan sea slug widely recognized for its vibrant, non-cryptic coloration. Often considered an iconic species of the Great Barrier Reef, it is frequently featured in marine educational materials due to its distinct appearance and behavior.

Distribution & habitat

This species is widely distributed throughout the Indo-West Pacific, including the Indian Ocean and the western and central Pacific. It is commonly found in reef flats and similar shallow marine environments, often in close association with its specific algal food source.

Appearance

Unlike many of its relatives, this slug displays bold black, yellow, and orange patterns. Its body is covered by large, flattened, leaf-like projections called cerata, which are often compared to butterfly wings. These cerata typically feature a vivid white margin, followed by a golden band and numerous golden spots on both surfaces. The animal also possesses long, bifurcated rhinophores that help it navigate its environment.

Biology & behavior

This slug employs effective defensive strategies, including the production of distasteful secretions to deter predators. It is also capable of autotomy, the ability to readily shed parts of its cerata when disturbed or irritated. When moving, the slug often elevates and curls its cerata, though it can flatten them like scales while at rest. If strongly stimulated, it can swim by flapping its cerata in coordinated waves.

Feeding

As a specialized herbivore, it feeds exclusively on the green alga Chlorodesmis fastigiata, commonly known as turtle weed. It uses a specialized radula to puncture the algal cell walls and extract nutrients.