70.012 BF1711  –  Geometridae –  Sterrhinae – Idaea trigeminata – Treble Brown Spot – (Haworth, 1809) Adult Macro:  CAT 2 – Can be confused with other species – Good photographs maybe required – Can be confused with other species       PDF Icon – click for Adult Macro Verification Guidelines

Brown –  Significant Record / Very Rare / Vagrant    
Taxonomy:   Macro   >>  Geometridae  >> Sterrhinae
ID Difficulty:  amber  – care required in the identification process, as confusion with similar species is likely – quality photographs required.
Confusion Species:  Single-dotted Wave; Small Fan-foot
ID pointers: Unmistakable and strikingly marked – as the name suggests, there are three brown spots in the lower area of the trailing edge of the forewing.
Distribution:  (First record: 1980 )  –  (Last record: 5 July 2025 at Darwin Forest, Matlock )  –  Current status unknown possibly a vagrant – 1 record in 1980. During recent moth record verification, two 2023 records were discovered from Darwin Forest, near Matlock by Dave Evans. One on 26/07/2023 & one on 27/7/2023. Possible re-catch of the same moth. These are the first reported since 1980. Another record from Darwin Forest on 5/7/2025 (seems this species maybe established at this site albeit a small isolated population)
General Comment: None
Flight Period: May /  June /  July –  On the wing – May – July Moth Activity: Nocturnal   – and is attracted to light Photographed: Yes –  Photographed By: Dave Evans  © All Rights Reserved
*** Last updated on 13 January 2026 by TD ***
Wingspan: 23-25mm
Forewing: 10-11mm
Food Plant: Knotgrass and Ivy.
Last Recorded Year: 2025
First Recorded Year: 1980
Last Recorded By – Dave Evans
Last Recorded General Area – Darwin Forest, Matlock

Selected Images:  Darwin Forest – 26/7/2023 – Dave Evans © Darwin Forest (2025) – Dave Evans©

 
 


 

Distribution Map for Idaea trigeminata

Found 6 records
    ↳ from 2026+
    ↳ 3 from 2020 - 2025
    ↳ 3 from Before 2020
Flying
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

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.

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.


NBN Atlas UK Distribution for – Idaea trigeminata

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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.

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Monthly Records By Year: Idaea trigeminata
( data includes both Larvae and Adult Stages )

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


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

Shading shows moth presence between dates

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Recordings By Year: Idaea trigeminata
( All data includes both Larvae and Adult Stages )
Annual Growth Rate (AGR): Idaea trigeminata
AGR: 0%   |   Total % Change: 0%

Hectad (10kmx10km) Coverage: Idaea trigeminata
( data includes both Larvae and Adult Stages )

Flight Periods – Indicative –vs– Recorded Data
Idaea trigeminata
( 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 2020-2026.

Records Behind the Map and Charts - Idaea trigeminata – 6 records available

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

Site NameTetradDateCountStageSource
Darwin ForestSK26X05/07/20251adultvc57_irecords_extract
Darwin ForestSK26X26/06/20231adultvc57_irecords_extract
BelperSK34U12/06/20231adultvc57_irecords_extract
The Meads, Shipley Park, HeanorSK44H13/07/20191adultDanes_2019-2021
Johnnygate, Common Side, ChesterfieldSK37C01/08/19901Adultvc57_danes_bc_data
Johnnygate, Common Side, ChesterfieldSK37C14/07/19901Adultvc57_danes_bc_data

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