Britain's moth population has plummeted by a third with 75 per cent of species in decline, according to a report released today.
The dramatic fall in numbers over the past 40 years, blamed in part on climate change and habitat loss, is worrying scientists because of the knock-on effect on bats and birds and invertebrates that feast on the insects.
The scientist Sir David Attenborough branded the statistics "significant and worrying" yesterday, adding: "Moths are valuable indicators of what is happening in our countryside. Other insects too are almost certainly in decline."
The new report, The State of Britain's Larger Moths by Butterfly Conservation reveals that the number of larger moths has decreased by 32 per cent in less than 40 years. Southern Britain has been the worst hit as areas south of York have seen moth populations devastated by 44 per cent since 1968 and it is estimated that some 75 per cent of species are in serious decline.
Of the 337 common moth species assessed for the report, the Dusky Thorn has had the highest rate of decline, in the region of 98 per cent. "If Britain's human population of 55 million in 1968 had undergone a similar decrease to that of the Dusky Thorn we would be left today with only enough people to populate Birmingham, i.e. about one million," said a spokesman for Butterfly Conservation.
The Garden Tiger moth population decreased by 89 per cent from 1968 to 2002. This is the one species where there has been significant research into its decline - and climate change has been identified as the most likely cause.
Moths are integral to the food chains of Britain's wildlife as the four most common garden birds feed on them or their caterpillars, and in many cases they are eaten by nestlings as well as by adults. All 16 British species of bat also feed them to some extent.
This month, The Independent reported on a study by Kate Vincent, a researcher at De Montfort University in Leicester, that links a decline in house sparrows to a fall in the numbers of insects and other invertebrates.
Moths are closely related to butterflies, but whereas there are only around 70 species of butterfly seen regularly in the UK there are 2,500 species of moths. The insects are artificially split into two groups, the larger moths (macro-moths) and the smaller moths (micro-moths). There are about 900 species of larger moth which have been recorded in the UK. The Butterfly Conservation report claims that since the late 1960s at least 62 moth species have become extinct.
In some urban areas losses are calculated to have been in the region of 50 per cent. In the north of England and in Scotland numbers have remained stable. "This pattern indicates a response to climate change," said a spokesman for Butterfly Conservation.
Data for the survey was collected by Rothamsted scientific institute from a nationwide network of moth light-traps established in 1968. "This long-running data set is unique and has highlighted a very serious ecological issue, the decline of common insects," said Martin Warren, of Butterfly Conservation.
Species in decline
GARDEN TIGER: A stout, hairy moth with chocolatey-brown and cream patterned forewings and orangey-red with black spots on hindwings. Its population decreased by 89 per cent from 1968 to 2002. Climate change is the most likely cause for its decline
CINNABAR: A day-flying moth which is easily spotted because of its bright red and black colouration. It is found throughout southern Britain and in coastal areas of Scotland, but in far fewer numbers. The survey showed it to be down by 83 per cent.
ARGENT & SABLE: A day-flying species which is most active in sunshine near boggy hillsides and moorland. It has black (sable) and silvery-white (argent) fore and hind wings with a white central band. It is on the priority list for conservation and was not included in the survey because it was already rare in 1968. It is hard to find in southern Britain.