72.037 BF2035  –  Erebidae –  Arctiinae – Thumatha senex – Round-winged Muslin – (Hübner, 1808) Adult Macro:  CAT 1 – Distinctive species unlikely to be confused with others –       PDF Icon – click for Adult Macro Verification Guidelines

Green –  Rare / Uncommon / Scarce   
Taxonomy:   Macro   >>  Erebidae  >> Arctiinae
ID Difficulty:  green  – easy to identify, generally distinctive and unlikely to be confused with other species.
ID pointers: A small and delicate looking moth, that is cream-coloured with very broad and rounded, slightly translucent wings. The forewing has a small and noticeable dark central dot and usually two rows of dark spots or dashes. 
Distribution:  (Last record: 1 July 2025 at Glossop )  –  Lastest record in 2024 – A new species for Derbyshire in 2016 when one was recorded in a garden trap in Belper. The record was submitted but never published. Steve Thorpe trapped a single individual in his garden moth trap at Breaston on 30th June 2020, then a further 19 in 2021, and a further 3 in 2022, all from the same site. Another single individual by Steve at Breaston overnight on 30th June 2023 and another from a garden moth trap in Sandiacre late June 2023. Steve’s garden backs onto Golden Brook Nature Reserve at Breaston, clearly this is a “Hotspot” for this species, and maybe the main site in the county.
Flight Period: June /  July /  August /  –  One generation on the wing June – August. Moth Activity: Nocturnal   – and is attracted to light Photographed: Yes –  Photographed By: Steve Thorpe, Christian Heintzen  © All Rights Reserved
*** Last updated on 21 July 2025 by WS ***
Wingspan: 15-20mm
Forewing: 10-11mm
Food Plant: Dog lichen (Peltigera canina), as well as various mosses.
Last Recorded Year: 2025
Last Recorded By – Christian Heintzen
Last Recorded General Area – Glossop

IMAGES BELOW:  Breaston 2020 and Breaston 2023 – By Steve Thorpe © / Glossop 1/7/2025 – Christian Heintzen©

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Distribution Map for Thumatha senex

Found 24 records
    ↳ 3 from After 2025
    ↳ 18 from 2020 - 2024
    ↳ 3 from Before 2020

If the Map Layers function fails, just refresh the page and it should be OK after. Use the +- zoom on the top left, or on a tablet, use two fingers to zoom. Remember, the last layer you ticked is the one which displays the popup information - they sit on top of each other - de-select then re-select, to see the popup values.

******* Choose ONLY one at a time, of either Monad, Tetrad or Hectad Distribution - each has it's own set of data. Also, the distribution maps cover ALL recorded data. *******

Bedrock Geology ** indirectly affects moth distribution by influencing the type of habitat and food plants available in an area. In turn, this may affect the types of moths that can thrive, or where they can most likely be found.

Land-cover * shows the variety of land-cover within the VC57 area, based on the CORINE (Coordination of Information on the Environment) forty-four thematic classes of land-cover. This will show, to a greater or lesser degree, the number and variety of moths found in different land-cover types. The UK continues to operate within the Copernicus programme, with the UK Centre for Ecology & Hydrology (UKCEH) providing Corine Land Cover (CLC) datasets for the UK and its territories.


NBN Atlas UK Distribution for – Thumatha senex

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Note – the NBN Atlas datasets are listed in the map below and vary in their currency (uptodateness) – however, the map does give a general indication of the moth's distribution across the UK.

Visit NBN Site


Monthly Records By Year: Thumatha senex
( data includes both Larvae and Adult Stages )

Monthly Counts By Year: Thumatha senex
( data is based on 'Adult' stage records only. )


First/Last Recorded Dates: Thumatha senex
Adult-only & Anything [Larvae, Pupae, Adult, Mines]

Shading shows moth presence between dates

Click the colour discs below to Select/De-select as Required

Recordings By Year: Thumatha senex
( All data includes both Larvae and Adult Stages )
Annual Growth Rate (AGR): Thumatha senex
AGR: -8.1%   |   Total % Change: -66.7%


CUSUM Analysis: Thumatha senex
About this chart: CUSUM (Cumulative Sum) charts track long-term trends in moth populations [ filtered by 'Adult' and 'Mine' life stages ] by showing whether each year’s counts are above or below the historical average. Even small shifts build up over time, making trends of growth, stability, or decline easier to see. CUSUM highlights trend-consistency — asking: “Across the years, have moth counts mostly stayed above or below average?”
The data sample has 20 gap year/s here (zero records) between 2000 and 2025. The moth may have been present in those gap years, but no data was available. Too many year-gaps may exaggerate or skew the chart.

Counts for the current year (2025) are pro-rated based on data available up to month 7 (July) to provide a full-year equivalent.

Purple line rises = years better than average; falls = years worse than average.
Peak (best year) Trough (worst year) Growth periods Decline periods
Population peaked around 2021, reaching above average levels. The lowest population point occurred near 2020, showing a significant decline.

What the Y-axis "Cumulative Deviation" means: Cumulative Deviation shows the running total of how each year’s moth population count differs from the long-term average. i

Hectad (10kmx10km) Coverage: Thumatha senex
( data includes both Larvae and Adult Stages )

Flight Periods – Indicative –vs– Recorded Data
Thumatha senex
( data includes Adult Stage only )

Flight Period chart – the grey hatched area above, which can cross one or more months, pictorially represents the best guess we have for this moth's flight periods [month/s]. The coloured lines represent the actual months seen in flight, from site observation records received between 2020-2025.

Records Behind the Map and Charts - Thumatha senex – 24 records available

Listed by Year - descending - scroll across to see all table columns

TaxonSite NameTetradYearDateCountStageSource
Thumatha senexChaddesden, DerbySK33T202511/07/20251adultvc57_irecords_extract
Thumatha senexChaddesden GardenSK33T202519/06/20251adultvc57_irecords_extract
Thumatha senexGlossop, Hague Street, Hay MeadowSK09G202529/06/20251adultvc57_irecords_extract
Thumatha senexBuxton SK, UKSK07S202310/07/20231Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202307/07/20232adultvc57_irecords_extract
Thumatha senexSandiacreSK43T202308/07/20232adultvc57_irecords_extract
Thumatha senexLadycroft AveSK07S202309/07/20231adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202323/06/20231adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202330/06/20237adultvc57_irecords_extract
Thumatha senexSandiacreSK43T202325/06/20231adultvc57_irecords_extract
Thumatha senexJim Mart Nature ReserveSK36S202324/06/20231Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202216/07/20221Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202219/07/20221Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202225/06/20221Adultvc57_irecords_extract
Thumatha senexNot givenSK22F202108/07/20213Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202108/07/20214adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202118/07/20218adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202120/07/20217adultvc57_irecords_extract
Thumatha senexDrakelow, Derbys.SK22F202108/07/20213adultvc57_irecords_extract
Thumatha senexBuxton SK, UKSK07S202001/08/20201Adultvc57_irecords_extract
Thumatha senexWoodland AveSK43R202030/06/20201adultvc57_irecords_extract
Thumatha senexFindern Close, BelperSK34P201224/07/20123Adultvc57_danes_bc_data
Thumatha senexAshbourne (site not precise)SK14T191101/01/19111Adultvc57_danes_bc_data
Thumatha senexAshbourne (site not precise)SK14T191101/01/19111Adultvc57_danes_bc_data

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