Extensive larvae damage (Wikimedia commons)
Occasionally, I come across books which have served as a meal for some species of bug. Usually, this is historic damage, but it is always good to be on the look-out for more recent attacks. This is particularly important if books are kept in a damp environment (which is not good for them for a number of reasons!). The most common insect pests which target books are woodborers, such as the furniture beetle (Anobium punctatum), death-watch beetle (Xestobium rufovillosum) and grazers, such as silverfish (Lepisma saccharina) and booklice (Lipsocelis bostrychophilus).
A larva has obviously made its way through this page. Usually, a woodborer’s tunnel can be traced through several gatherings within a book
The larvae of furniture beetle and death-watch beetle love wooden boards and will also happily eat their way through closed books (see images above). An indicative sign is small piles of frass where the adult beetle has made its way out of the object, but most commonly the only evidence left are the little flight holes on the outside (even on the fore-edge) and the tunnels through the book. These woodborers like a cold and damp environment and within their 2-3 life cycle can cause quite a lot of damage. Keeping the relative humidity (RH) below 55% helps to contain them.
Insects have clearly targeted inside board edge – probably going for the adhesive used to attach the pastedown to the edge of the paper cover. Interestingly, although the outside of the cover also shows grazing damage, the insects (either booklice or silverfish) appear to have preferred the glue on the inside!
Silverfish and booklice, on the other hand, tend to graze on the surfaces of bindings and paper (see image on the right and below), being attracted by animal-based coatings (such as gelatine sizing on paper, and starch- or gelatine-based adhesives), organic material (i.e. dust), and microscopic mould (more on this particular pest in a later post). Silverfish like a cool, very damp (70-80% RH), and dark environment, while booklice prefer a higher temperature (upwards of 25 degrees Celsius).
Grazing on the front cover of Noon’s India.
The ways to prevent insect damage are: to monitor a collection for any activity; to maintain a stable environment with low RH levels; and to keep dust to a minimum.
NB: I am not a book conservator and these observations are based on my untrained understanding of these issues. If in doubt, consult a professional conservator!