Have you ever been described as a bookworm?

We hope the only bookworms encountered in our reading rooms are of the Studious genus, but did you know that there are a whole host of pesky pests out there hungry for paper? Fires and floods are usually the scenarios we think of when we hear about damaged books, but books are also susceptible to pest damage. “Bookworm” is actually a generic term and doesn’t apply to any particular species, although it is often used to describe the Anobiid beetle (Anobium punctatum).

Figure 1: The larvae of furniture beetles, Anobium punctatum, attack wooden book boards, shelving, frames and compressed paper. Copyright DBP Entomology. 

Where the passionate reader sees inspiration and literary genius, the pest sees a delicious and satisfying papery meal. Holes in books and bindings, large chewed areas and scraped surfaces are all evidence of pest attack. Thankfully, damage like this is largely historic and it is a matter for conservation rather than pest control. Our Preservation Advisory Centre (closed since March 2014) produced a free to download information booklet on Managing pests in paper-based collections written by Consultant Entomologist David Pinniger. Although there are physical and chemical treatments to control infestation, it is much cheaper and far more effective to use preventive methods. Here we take a look at a few of the culprits.

Name: Silverfish (Lepisma saccharina)
Likes to eat: Paper

Silverfish (or fish moths) are nocturnal wingless scaly insects (10-15 mm) associated with damp conditions and require a localised humidity above 70-80%. They are named in light of their silvery exterior and slithery fish-like movements. 

Figure 2: The Silverfish is a primitive insect with three bristles called cerci at the tail end where the abdomen tapers. Copyright Aiwok. 

Post-meal evidence includes irregular holes in paper and ragged, scraped surface areas. If they are particularly greedy they will preferentially target areas with glue or ink which may be more nutritious.

Figure 3: Silverfish (sometimes known as fish moths) leave irregular holes in paper around a scuffed surface.  Copyright DBP Entomology.

Name: Varied carpet beetle (Anthrenus verbasci)
Likes to eat: Animal glue

The varied carpet beetle is the most common species found in Great Britain. The adults are 2-3 mm long with a grey and gold scaly exterior. They enjoy flying in warm weather and typically hang-out on window sills – the carpet beetle equivalent of the shopping mall. It is the offspring that causes damage to collection material. Young offenders hatch from eggs into hairy larvae (< 1 mm), and grow up to 5 mm. They shed their skins as they develop and tend to wander around randomly chewing holes in bindings and mounts where animal glue resides.

Figure 4: The varied carpet beetle, as well as being partial to animal glue, can be found dining on wool, fur, feathers, silk and skins.  Copyright André Karwath

 

Name: Biscuit beetle (Stegobium paniceum)
Likes to eat: Starch and dried food

Figure 5: The biscuit beetle bores holes in harder materials and emerges leaving a symmetrical exit hole. Copyright Sarefo

They may sound friendly (or tasty!), but beware the biscuit beetle. Unlike woodworm larvae which eat wood and cellulose, biscuit beetle larvae bore holes and cavities in paper, papier maché and starch-rich composite board in books and boxes. They are also known as the Drugstore beetle or the Bread beetle with adults reaching about 2-3 mm long.

 

Name: Woodlouse
Likes to eat: Damp paper and cardboard

Figure 6: Woodlice Porcellio scaber (left) and Oniscus asellus (centre) in wood  

The woodlouse is not an insect but belongs to the Crustacea group which includes shrimp and crabs. They love damp high humidity conditions such as rotting wood or vegetation and cause damage by grazing on damp paper and cardboard if located nearby. Most people have encountered woodlice by disturbing old logs outside and watching as they scurry around in bewilderment. They cannot survive in dry conditions so when found inside have usually wandered in from a damper outside environment, and therefore do not live very long.

Land and air attack

It’s not just insects that attack books, rodents and birds also play their part. Mice can be particularly damaging as they tend to gnaw materials habitually to keep their teeth sharp, while females shred paper to make nests for their young.

Figure 7: Mouse damage Copyright DBP Entomology

Birds are unlikely to directly target books for nutrition, but as anyone who has tried to shoo a pigeon out of a room will know - bird droppings can cause unsightly stains and be very corrosive.

Integrated Pest Management

Figure 8: One of the first signs of a furniture beetle attack is frass (insect excrement) which is pushed out of the larvae tunnels when the adult furniture beetle emerges. Copyright DBP Entomology.

Pests will only usually damage material because they are seeking nutrition. Collection items boasting mouth-watering edible materials such as wooden boards, textiles, adhesives, gelatine and starch can satisfy the pickiest of pests. Prevention is always better than cure so it is important to be vigilant for the signs of an infestation. If you are unsure about a potential pest problem contact the Preservation Advisory Centre for some helpful advice.

Christina Duffy (@DuffyChristina)