It’s what’s inside that counts: computer-aided tomography for evaluating the rate and extent of wood consumption by shipworms

Abstract

Experiments were done to investigate in situ colonization of pine wood blocks by marine wood borers at the mouth of a small mountain river in the foothills of the Eastern Pyrenees. Standardized blocks were recovered after remaining underwater for increasingly long durations, until the available resource was exhausted by the shipworms assemblage that developed. Computer-aided tomography (CT) was used for visualizing and quantifying biogenic structures into the wooden blocks. The biodiversity survey of the wood pieces colonized indicated that up to three species of shipworms shared the resource at the same time. The specific wood consumption rate of Nototeredo norvagica was estimated 185 mm 3 ind −1 day −1. The quantification of voids created by shipworm crowding indicated that total tunnelling represents, on average, 60% of the initial volume of a wood block, revising upward earlier estimates of wood destruction by 28%. CT analysis provides the quantitative measurements necessary to parameterize individual-based growth models linking wood consumption with the species diversity of shipworm assemblages.

Cultivation and Fluorescent in situ hybridization suggest that some shipworm species acquire endosymbiotic bacteria through indirect horizontal transmission

“…Previous work on this model shipworm revealed they harbor endosymbiotic, intracellular gill bacteria [15,19]. These communities provide 9/20 important cellulase and nitrogenase enzymes to their hosts [3,15,16,[27][28][29] and are relatively simple, composed of Teredinibacter turnerae and other gram-negative proteobacteria [15,23].…”

Sources partitioning in the diet of the shipworm Bankia carinata (J.E. Gray, 1827): An experimental study based on stable isotopes

“…Growth in the genus Bankia is generally fast and produces adults of large size(Haderlie and Mellor, 1973;MacIntosh et al, 2014). This species is reported in the studied area together with Lyrodus pedicellatus, Teredo navalis and Nototeredo norvagica(Charles et al, 2018). As population dynamics patterns depend on reproductive modes, differences must be expected in food source partitioning between shipworm species according to the level of exhaustion of the wood resource.The measurement of isotope ratios on the whole body of the borers corresponded to the isotopic signature of the flesh of the shipworms including those of the bacteria from the digestive tract and the endosymbionts from the gills.…”

Durability and protection of timber structures in marine environments in Europe: An overview

“…Attack by teredinids is difficult to detect with the naked eye, but a magnifying glass can more easily display entrance holes of larvae. The degree of attack is usually analyzed by x-ray, when non-destructive evaluation is required, such as computer-aided tomography (Charles et al 2018), but can also be investigated by density measurements or strength determination as well as wood sample preparation and borer species identification (Turner 1966).…”

“…An updated version of the different Limnoriidae can be found in the IRG-WP article of Cookson (1990). In addition to the research on individual wood borer species, the different stages of wood fragmentation by the different wood borers has been described (Nishimoto et al 2015), as well as the rate of wood material consumption (Charles et al 2018).…”