C. Tupper, A.J. Pitman, S. M. Cragg
Copper Accumulation in the Digestive Caecae of Limnoria quadripunctata Holthius (Isopoda: Crustacea) Tunnelling CCA-Treated Wood in Laboratory Cultures
Summary
To investigate the mechanisms by which the isopod Limnoria tolerates copper, chromium and arsenic
when tunnelling CCA-treated wood in the marine environment, digestive caecae of specimens of L.
quadripunctata from CCA-treated and untreated Pinus sylvestris sapwood were examined using transmission
electron microscopy (TEM) and energy dispersive X-ray detection (EDX). Copper-containing
granules were found to be present in the small cells of the digestive caecae (midgut) of Limnoria from
both treated and untreated wood. However, individuals tunnelling treated timber contained a greater
number of granules, with six types of morphology being distinguished of which only two were present
in Limnoria from untreated wood. The presence of copper-containing granules in Limnoria from untreated
timber may be explained by the ability of this isopod to acquire and store copper from seawater for
use in enzymes and blood pigments. The increased number of copper granules in individuals tunnelling
treated wood was believed to result from elevated levels of this element in the food substrate. This ability
to store copper allows these organisms to tolerate this metal in the wood substrate and may explain
how this organism is able to attack CCA-treated wood in service. No chromium, or arsenic, was detected
in the digestive caecal cells.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 54, 10/2000
Pages: 570 - 576
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