The fabric of some of the UK’s most important historic buildings are under attack by the clothes moth and other pests, thanks to climate change.
Historic Royal Palaces looks after six palaces in England and Northern Ireland and says, that over the last decade, some areas of Kensington Palace have experienced twice the number of common clothes moth attacks than usual.
Clothes moths in the home get a bad press, but there are over 2,500 species in Britain, while there are fewer than 70 butterfly species. Moths live in a wide range of habitats, but only a handful of them can be considered a problem.
“Moths are declining in the UK. Studies have found the overall number of moths has decreased by 28% since 1968.
The situation is particularly bad in southern Britain, where moth numbers are down by 40%. Many individual species have declined dramatically in recent decades and over 60 became extinct in the 20th century. Sadly, among the species which have declined are many beautiful moths which were previously very common and frequently seen in our gardens.
These alarming decreases in moth populations are not just bad news for the moths themselves, but also have worrying implications for the rest of our wildlife. Moths and their caterpillars are important food items for many other species, including amphibians, small mammals, bats and many bird species.
Moth caterpillars are especially important for feeding young chicks, including those of most familiar garden birds such as the Blue Tit and Great Tit, Robin, Wren and Blackbird. A serious decline in moth numbers could have disastrous knock-on effects for all these wildlife species. Already, research has indicated that a decrease in the abundance of bats over farmland is related to the decline in the moths that they depend on.”
Since 1914, 56 moths have become extinct, although six of these have since recolonised or been re-discovered.
The little critters now have up to three breeding cycles a year, up from the usual one or two a year previously seen.
Climate change has given rise to longer and wetter summer weather – ideal breeding conditions for moths – and, while the early onset of winter and more frequent cold periods might be thought to be helpful, in fact the palaces have been forced to switch on the heating more often, again making excellent conditions for the insects to breed.
Other pests also threaten the historic objects contained within the historic buildings: silverfish can munch through soft furnishings and books, wallpaper, plaster and any other household item that contain starch or cellulose; furniture beetles can bore deep into wood; and damp conditions suit both creatures.
The royal palaces have a team of preventative conservators who have so far kept the problem under control using a programme of insect pest management. Many of the historic objects would be damaged using modern chemical methods of cleaning, which use substances unsuitable for such items, but increased cleaning, that removes both the insects and their food source quickly, also helps.
Another resource in the armoury against the creatures is the control of damp. Methods such as keeping furniture away from walls and improving general ventilation of the rooms, work alongside more complex interventions, such as controlling the humidity or installing specialist humidistatically controlled conservation heating, which balances the temperature to reflect the levels of humidity.
There are hundreds of more useful moth species in the UK and many are in decline. However, common clothes moth and case-bearing clothes moth numbers are increasing, and English Heritage recorded an increase of 216% between 2012 and 2016.
If you’re suffering from an invasion of clothes moths at home, there are ways of tackling them. Their presence is usually evident in clothes, curtains and carpets – anything derived from animal origin, such as wool, fur and feathers – but even insulation can be targeted by the little pests. They will not munch cotton or man-made fibres.
Case bearing clothes moths like humidity, but common clothes moths are quite happy in a dry environment. The damage is not caused by the adult moth, but at the larval stage.
Regular vacuuming will help reduce the risk, and if you think you have moth larvae in your favourite jumper you can freeze it (for at least two weeks) to kill the larvae.