Common identification mistakes

Why know mistakes in advance

Most identification errors are not random — they follow patterns. Some species pairs are always confused; others mislead because of sexual dimorphism or seasonal forms. Knowing the pitfalls, you will deliberately check the right trait from the first look.

Mistake 1: male and female as “different species”

Sexual dimorphism in butterflies is often so strong that male and female are taken for different species.

Brimstone (Gonepteryx rhamni): male bright yellow; female pale greenish, almost white. In flight they seem like two butterflies. What unites them is the angular wing shape and a bright orange spot in the centre of each wing (both sexes).

Blues (almost the whole group): male blue or azure above; female brown or grey. In flight both colours may show. Identify them by the underside, where the pattern is the same in both sexes.

Orange tip (Anthocharis cardamines): male white with a large orange spot; female white without orange, almost like a small white. Tell them by the characteristic green “marbled” pattern on the hindwing underside (both sexes).

Purple emperor (Apatura iris): male with bright blue sheen at certain angles; female brown without sheen, much larger. People often think the blue male and the large brown female are different species.

How to avoid: if you see an unusual “brown” butterfly without bright marks — check whether it is the female of a known species.

Mistake 2: spring and summer broods as “different species”

Some species have two generations per year that look very different.

Map butterfly (Araschnia levana) — a classic example. Spring brood: russet with a dark pattern, like a small fritillary. Summer brood: dark brown with a white band, like a small admiral. One species — but in the field they are often treated as two.

How to tell them apart: in both broods the underside is characteristic — a fine mesh of yellow and brown bands. This trait is constant.

Common blue (Polyommatus icarus): spring brood smaller and duller; summer brood larger and brighter. Females are especially variable — sometimes with blue scales at the wing base, sometimes entirely brown.

How to avoid: if you cannot ID a small russet or dark nymphalid — check whether it is a seasonal form of the map butterfly.

Mistake 3: large white vs. small white

Both white, both on crucifers — a classic confusing pair.

Main field mark: spots on the male forewing — two in large white, one in small white. If the butterfly is female — look at the hindwing underside.

Mistake 4: small tortoiseshell vs. large tortoiseshell

Both orange with black spots — similar but distinct.

Main trait: 4 forewing spots in large tortoiseshell vs. 3 in small tortoiseshell.

Mistake 5: look-alike blues

Male blues are almost all blue above. They must be told apart by the underside.

Common blue (Polyommatus icarus) vs. silver-studded blue (Plebejus argus):

• Icarus: underside with orange marginal spots and black dots; female often without orange spots
• Argus: same general scheme, but in Argus the orange spots on the hindwing underside have metallic green “pupils” — absent in Icarus

Common blue vs. chalkhill blue (Polyommatus bellargus):

• Icarus: blue with a violet tint; dark marginal border
• Chalkhill blue: more intense bright sky-blue; border contrastingly dark with a white chequered fringe between dark veins — a characteristic mark

Mistake 6: look-alike fritillaries

Large russet nymphalids with “silver” below — a difficult group.

Main method: hindwing underside. Silvery spots are unique to each species. Hard to memorize at once — but in the field you can photograph the underside and identify at home.

Most common species in central Russia:

• High brown fritillary (Argynnis paphia): large; male with 4 black stripes on the forewing upperside (pheromone areas)
• Niobe fritillary (Argynnis adippe): slightly smaller; silvery spots below separated by brown bars
• Small pearl-bordered fritillary (Boloria selene): smaller; on wet meadows

Mistake 7: mistaking a moth or noctuid for a day-flying butterfly

Several nocturnal and crepuscular species fly by day or resemble day-fliers.

Burnets (Zygaenidae): bright red-black or blue-red; fly by day on flowers. Can be taken for beetles or day-flying butterflies. Burnet antennae are thread-like or clubbed — look closely.

Tiger moths (Arctiinae): some species fly by day. Garden tiger on flowers is a typical daytime sight. Nocturnal sign: hairier body and horizontal wings at rest.

Clearwings (Sesiidae): transparent or semi-transparent wings, body with yellow bands — mimic wasps and hornets. Fly by day. If you see a “wasp” with antennae and wings — check for a clearwing.

Mistake 8: worn butterfly

In late season (August–September) many butterflies fly with worn, faded wings. Pattern rubs off, colour pales. Such a butterfly is often taken for another species or not identified at all.

How to cope: look at overall silhouette and wing shape — they do not wear away. Seek remnants of key traits: eyespot shape, general pattern type, underside colour (it wears less).

Practical tips

1. Always photograph the underside — for blues, fritillaries, and nymphalids it is the decisive shot.
2. Determine sex before searching for the species — that immediately narrows candidates.
3. Check the season — if the species “does not fit” the time of year, it may be another brood or another species.
4. Upload to iNaturalist — the community will correct mistakes; it is one of the best ways to learn.
5. Do not worry about unresolved IDs — female blues, fritillaries, and some noctuids cannot be identified even from good photos without a specialist.

To start — identification by colour and by wing shape.