Species Account

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Summary Data

Season (Adult / Immature):

National Status: Nb

Local Status: Scarce and very local resident.

Local Record: Grade 3   See here for explanation

Flight time: One or two generations, Jun-Aug, (Aug-Sep).

Forewing: 10-11mm.

Foodplant: Dewberry, Bramble, Raspberry and Strawberry.

Regional breakdown:

Year first recorded1973
Year last recorded2014
Number of records283
Number of individuals490
Unique positions18
Unique locations20
Adult records283
Immature records0

For the county, we have a total of 283 records from 20 sites. First recorded in 1973.


74.002 Kent Black Arches 2020 abundance
© C H Fletcher
74.002 Kent Black Arches 2020 map
© C H Fletcher
74.002 Kent Black Arches 02
© Ian Marshall, 4 Jul 2017
74.002 Kent Black Arches 01
© Dave Shenton

Species Account

Sutton & Beaumont, 1989: This species usually occurs on the south coast where it became established by immigration in the 1950s (Williams, 1958). The first northern record in Britain occurred in 1973 in Yorkshire, trapped by P.Q. Winter.

Beaumont, 2002:
VC61. Spurn, 1.8.1991, 29.7.1992 (BRS); Bridlington, 9.8.1996 (KAB); Rudston, 12.8.1996 (ASE).

Argus 58, 2009: There have been no records away from its stronghold at Spurn since 1996. The Spurn colony has grown to record levels this year so we may see some further expansion in range.
VC61. Spurn area, 39 records of 64 moths from 3.7-12.8.2009 (BRS, PCA, MJS).

Current status (CHF, 2011): A large increase at Spurn though the moth has disappeared from locations further up the coast.

2020 (CHF): What on earth has happened to Kent Black Arches. It’s another relative newcomer to the country, being first found in 1859, and it’s been spreading all over Europe. I’ve been reading the Atlas. It sounds so rosy it is worth quoting in full. “Formerly found mainly in south coast counties of England, this species has spread rapidly northwards and inland. Its recent distribution trend shows a large increase and the moth now occurs more widely in southern England and north, along the coast, to south-east Yorkshire”. OK great. So, it’s another moth that’s invading and we’re soon going to see it everywhere.

The first Yorkshire record was as long ago as 1973 when a wandering moth was trapped at Muston. We had to wait until the 1990s for any more records, at Spurn, Rudston and Bridlington, but it was 2002 when the invasion started properly and a colony was established at Spurn. We have had records every year since. Over the next few years, the Spurn colony grew rapidly and moths were seen up the coast as far as Hunmanby Gap. It became regular at North Ferriby and in 2017 even ventured across the VC63 border to Blacktoft Sands. So far so good.

But looking at records per year, 2012 was the high point with 41 records of 69 moths. Ignoring 2013 which is a statistical aberration as there was virtually no trapping at Spurn, the numbers have slowly and steadily fallen. In 2019 there were just ten records of ten moths. In 2020, just eight records of eight moths. The only encouraging signs were single moths at new sites at Hollym Carrs and Kilnwick. What has happened. Why would a rapidly expanding moth go into steady decline over just a few years? It doesn’t look like the sort of cyclical boom and bust you get with specific parasitoids. Global warming hasn’t suddenly gone into reverse. The Field Guide implies it isn’t too fussy with its diet and will eat “dewberry, bramble, raspberry and wild strawberry”, though Skinner simply says “dewberry”. Is dewberry declining in VC61? Again there are so many questions!

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