What's Eating Your Collection?

Blunder traps are a simple and efficient way of monitoring insects. They will be more effective if they are placed correctly. Pheromone traps with attractants may need to be used in a different way.

• Each trap should be given an individual number. This should be written onto the trap, along with the date of its placement. The number of the traps should be written onto a floor plan to show the position of the trap in the room.
• Position the trap on the floor, preferably in corners. Traps catch some insect larvae as well as adult insects. The adults spend a lot of time crawling rather than flying and the larvae cannot fly. Consequently, traps placed on shelves or on top of cupboards are largely ineffective.
• Only place traps in showcases if an infestation is present or the trap is felt to be the most effective method of monitoring.
• Ideally, place a trap in each corner of a room. Once a monitoring programme has been in use for a few years, it may be possible to reduce the number of traps once it is known what the background insect population is and where they are found. To begin with, a trap in each corner is helpful.
• Try to position traps where they will not be trodden on or stolen.
• If the room has an unused fireplace, place a trap in the fireplace, even if the chimney is capped. There may still be debris in the chimney that can sustain insects.
• If the trap you are using has a sticky strip on the bottom, take off the cover strip, rotate it through 90° and put the strip back. This will give two sticky areas either side of the cover strip. It won’t stick to the floor, but will give a trapping surface that will catch very small larvae.
• Place traps in every area that contains vulnerable collections as a minimum. Monitoring all rooms and spaces will give a true representation of the insects present in the building, but it may not be possible to monitor all areas.
• Think carefully about the type of trap that will be used. Blunder traps are available from a number of suppliers but some designed for catching cockroaches are not effective for museum pests.
• If bats are present in the building, triangle blunder traps as supplied must NOT be used. Bats can become stuck on the trap and this is a prosecutable offence. In this case, sides should be made for the blunder trap, leaving a gap of only 2mm or so. Alternatively, plastic traps that have a very small entry slot are available through Historyonics (see suppliers’ list).

Pheromone traps

Traps that emit clothes moth pheromones are available and these are very useful for monitoring the moth population. These take the form of lures that can be placed on blunder traps or plastic traps with impregnated card inserts. Moth pheromone lures are more effective when traps are placed above floor level when temperatures are above 18°C. This means they must be used together with blunder traps on the floor. Many types are available but the AF traps and lure boards have been shown to be the most cost-effective.