Gribble - Ecology

Ecology

Gribbles bore into wood and plant material for ingestion as food. The cellulose of wood is digested, most likely with the aid of cellulases produced by the gribbles themselves. The most destructive species are Limnoria lignorum, L. tripunctata and L. quadripunctata. Due to dispersal while inhabiting wooden ships, it is uncertain where these three mentioned species originated. Limnoriidae are second only to the Teredinidae in the amount of destruction caused to marine timber structures such as jetties and piers. L. tripunctata is unusually tolerant of creosote, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria. Gribbles bore the surface layers of wood, unlike the Teredinidae which attack more deeply. Their burrows are 1–2 mm diameter, may be several centimetres long, and have the burrow’s roof punctured with a series of smaller ventilation holes. Attacked wood can become spongy and friable.

Gribbles play an ecologically important role, by helping to degrade and recycle driftwood. Most seaweed boring gribbles attack holdfasts and their activities can cause the seaweed to come adrift especially during storms.

For defence, gribbles can jam themselves within their burrows using their uropods and block the tunnel with their rear disc-shaped segment, the pleotelson.

A number of crustaceans have evolved as commensals with Limnoriidae. Chelura are amphipods that inhabit the more severely attacked regions of gribble-attacked wood. Donsiella are tiny copepods that inhabit the brood pouch and body of Limnoriidae.