Diarsia brunnea
In 3 days ~10% in a week ~20%
Diarsia brunnea, the purple clay, is a moth of the family Noctuidae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775. It is found in most of Europe, east to Transcaucasia, the Caucasus, central Asia, Siberia, the Kuriles, Amur, Ussuri, Sakhalin, Korea, Japan, and China, including China's Tibet region.
The wingspan is 35–38 mm. Forewing pinkish or purplish-plum coloured; the costal half with a fulvous and yellow tinge; cell deep olive brown; claviform marked by a dark spot at its end; orbicular oblong, of the ground colour; reniform outlined or filled with ochreous; hindwing luteous (muddy yellow) fuscous; cilia pink.
Adults are on wing from July to August. Larva dark brown; dorsal and subdorsal lines pale, lateral lines whitish; a row of pale yellow dark-edged oblique stripes, and a yellow stripe across segment 11. The larvae feed on a wide range of herbaceous plants and shrubs, including Rumex species (including Rumex acetosella), Dryopteris filix-mas, Luzula sylvatica, Deschampsia flexuosa, Brachypodium sylvaticum, Vaccinium myrtillus, Vaccinium uliginosum, Prunus spinosa, Primula, Rubus, Urtica, Salix and Betula. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Pyrénées National Park | 🇫🇷 France |
Rare
Under 5% of wildlife watchers report a Purple Clay sighting in Pyrénées National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 940th most-seen of the 1277 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
June and July
In those months about 10% of wildlife watchers report a Purple Clay in Pyrénées National Park on a given day, against under 5% in August to May, the lowest months.
Between 10 pm and 1 am
Across all the parks we cover, that three-hour window holds the most Purple Clay sightings with a recorded time, and about half of them come between 6 am and 6 pm: it is seen both by day and at night.
3rd of 3
Of the 3 parks where we can rate Purple Clay sightings, Pyrénées National Park ranks 3rd at under 5%. The best odds are in Snowdonia National Park (United Kingdom, about 10%) and Bavarian Forest National Park (Germany, about 10%).
Same family: Noctuidae
The closest relatives of the Purple Clay that you can see in Pyrénées National Park (family Noctuidae, Cutworm Moths and Allies) are Silver Υ (about 10%), Cotton Bollworm Moth (about 10%) and Marbled White-Spot (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Purple Clay is recorded against all the insects logged in Pyrénées National Park (9 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
