Wood modification reduces the feeding rate of the wood boring crustacean, Limnoria quadripunctata
L S Martin, S Lande, M Westin, S M Cragg
Adult Adult Limnoria search for new wood once their current piece disintegrates from tunnelling. During this time, they do not have access to wood so experience a period of starvation and must feed again once settled. Wood modification offers protection to marine structures by reducing the feeding rate of Limnoria and therefore can reduce recruitment of adults from distant pieces of wood. Chemical modification, such as furfurylation, protects wood against damage by marine wood-borers, without the use of broad-spectrum biocides which can leach out into the surrounding ecosystem. Preservatives such as CCA have been restricted in the UK, EU, USA and Australia therefore, novel, more environmentally friendly products are required for use in marine environments.
In this study, individual Limnoria quadripunctata were fed continuously, starved continuously and starved then re-fed after two weeks on control or furfurylated wood. Two different drying/curing schemes in an experimental furfurylation process were used for modification of Pinus radiata. The treatments, which differed in peak temperature and total process time, resulted in approximately the same weight percentage gain. Treatment 1 with the lower peak temperature and longer process time and treatment 2 with the higher peak temperature and shorter total process time. Treatment 1 resulted in a slightly lower faecal pellet production than treatment 2 from L. quadripunctata that fed continuously and from those that were starved and refed. It was also more likely to cause mortality earlier on in the experiment, possibly due to incomplete polymerisation from the lower curing temperature. Although a long leaching period is required to remove extractives, this lower temperature drying/curing regime seems to be effective at both reducing the feeding rate of healthy adult Limnoria and individuals that have been starved for 14 days. However, treatment 2 also significantly reduced feeding rate compared to untreated wood.
Furfurylation is an effective treatment to protect wood against Limnoria attack, although drying/curing temperature and time and leaching time affect feeding rate and mortality. Treated wood is likely to impact animals that experience starvation, although further investigation is required to compare treatments 1 and 2 with changes seen in Limnoria refed control wood.