Everything made from organic material is edible to one pest or another (including insects and rodents), which makes our strongrooms a positive banquet hall. Therefore, it’s important that we implement the principles of Integrated Pest Management (IPM), which essentially cover Prevention, Monitoring, Identification and Solutions.
Prevention is far easier for us than a museum or historic house where there are multiple points of entry for pests: doors, windows, chimneys, basements, and where access is freely open to allow visitors to wander through. In contrast, our strongrooms only have two points of entry, which are sealed double doors, with only small numbers of staff entering throughout the day, thus limiting access to any insects that may want to enter. Good housekeeping however is still imperative, which is why no food or drink is allowed and the strongrooms are regularly cleaned to prevent any additional enticements.
Monitoring is carried out by placing sticky blunder traps around the building: in the strongrooms and the staff and public areas – you may have seen some if you have visited DHC. Insects predominantly travel along skirting boards as it’s safer, so the traps are placed along walls. Unfortunately, they do trap indiscriminately, and we often catch spiders. Whilst many people are not fond of our eight-legged friends, they eat pest insects for us and so we’re always a little sad to catch them. The traps are checked every quarter – a job we often give to willing work experience students!
Once caught, the insects need to be identified. Not all insects will eat archival material, so there are a number of specific ones that we keep an eye out for. These are some of them (not to scale!):
The traps can also tell us additional information, such as the direction the insects are coming from, quantities, and the environmental conditions of a building. For example, silverfish prefer high humidity, so a large number may suggest a damp problem.
If large numbers of insect pests are being caught then a solution will be required. This will depend on the type and severity of the infestation, but must always include dealing with the cause, which will be the only way to prevent further infestations.
Whilst we make every endeavour to keep insects from our own strongrooms, occasionally we deal with items that have been damaged by pests before they arrive here (we check archives for live insects before storing them in the strongrooms!). Although any damage to documents can be disastrous, they can also be in their own way quite aesthetically pleasing!
If you think you have a pest problem or have found an insect you want to identify there are some great online resources including:
What’s Eating Your Collection? (whatseatingyourcollection.com)
Museumpests.net | A Product of the Integrated Pest Management Working Group
Conservation Advice and Guidance | English Heritage (english-heritage.org.uk)
Identifying insects | Royal Entomological Society (royensoc.co.uk)