Warmer southern parts of England are more at risk from common clothes moths, according to a year-long survey led by English Heritage.
Members of the public were asked to monitor clothes moths in their own homes to help the heritage charity look after its collection of historic wool carpets, tapestries and period clothing.
The scheme Operation Clothes Moth was launched a year ago after English Heritage experts witnessed the numbers of common or webbing clothes moths double, and observed the appearance of the pale-backed clothes moth.
The survey, which saw thousands of traps handed out at English Heritage sites and received data from 42 counties, discovered an "alarmingly high" number of the new species, the pale-backed clothes moth.
It also revealed that the reported catch of the common clothes moth was significantly higher in London and the South East, where an average 23 moths were found per trap, than anywhere else in England.
The South West came second with an average of 17 moths per trap, while the East Midlands, North West and North East of the country recorded the lowest levels.
According to the Operation Clothes Moth results, flats or apartments are more susceptible to clothes moths as they have shared walls.
Clothes moth numbers were higher in older, pre-1950 properties as they have more voids, fireplaces and attics than modern houses, English Heritage said.
Amber Xavier-Rowe, English Heritage's head of collections conservation, said: "The response from the public has been brilliant and the data we've gathered has been invaluable in informing our understanding of the clothes moth threat.
"Now that we know where the clothes moth concentration is the highest, we can put in place extra measures to ensure that our historic houses in these areas are fully protected and preserved for future generations.
"We wouldn't have been able to do that without the public's help."
She added: "Operation Clothes Moth has really resonated with a lot of people who yes, want to help us protect our collections but also to protect their favourite woolly jumpers."
English Heritage has also drawn up a guide, based on 20 years of practical experience protecting historic collections from insect pests, to help homeowners defend their homes from infestations, which is going on sale on Tuesday.
The top tips for preventing clothes moth infestations include checking for moths in the creases, folds and behind labels of clothing, keeping items in vacuum bags, and taking out items from the wardrobe and giving them a good shake at least once a month to disturb the moths.