The marine isopod Limnoria quadripunctata degrades wooden structures in the sea and causes significant economic damage. Broad-spectrum biocides and naturally resistant tropical hardwoods have failed to prevent feeding by Limnoria and have caused ecological damage. Wood modification is now the favoured method, and resin-based modifications have been effective, while the efficacy of silica-based modifications is less certain. Therefore, two mineralizing-based treatments were tested against L. quadripunctata in a short-term laboratory assay. Treated and untreated Pinus sylvestris were exposed to L. quadripunctata for 22 days, and feeding rates were assessed by faecal pellet production. Mortality and moulting were also noted. Mandibles of surviving animals were prepared for scanning electron microscopy to examine the effect of treatment on the specialised surfaces. All treatments significantly reduced feeding rates. The changes in feeding rate of the treatment-fed animals suggest that leaching was a major factor in the resistance seen during the initial period of the experiment. Easily leached treatments do not make durable solutions, so the leaching characteristics of these treatments must be elucidated. The mandibles of all treatment-fed animals were also damaged, suggesting that abrasiveness and hardness of the wood had been increased. However, mortality and moulting did not differ significantly, so it is likely that the resistance to attack seen in this study is due to the treatments impairing feeding rather than toxicity.

Download document (540 kb)
free for the members of IRG. Available if purchased.

Purchase this document