An anatomical approach to investigating Lyctus brunneus feeding behaviour in oak sapwood

The feeding activity of wood-boring beetles leaves permanent anatomical traces in wood. However, the exact proportions of wood tissues consumed during larval feeding remain largely unexplored. This study presents a wood anatomical approach to infer the diet preferences of Lyctus brunneus larvae, a widespread powder-post beetle, using decayed oak (Quercus sp.) sapwood. Analysis of the sample revealed that larval development comprises three instars, marked by two moults, before reaching their final size. The diet primarily consisted of cells surrounding earlywood vessels and axial parenchyma, followed by latewood areas, including vessels, fibres, axial parenchyma, and a smaller proportion of rays. Notably, the relative proportions of tissues consumed remained consistent across larval stages. These findings advance our understanding of larval feeding behaviour and offer valuable insights for identifying insect damage in archaeological and historical wood remains. This approach can help distinguish the decay caused by Lyctus brunneus to other xylophagous insect species, aiding in interpreting wood decay patterns and contributing to reconstructing past environmental and cultural contexts.