Euphydryas anicia

Distinguished from Euphydryas editha and E. gillettii by lack of white spots on the abdomen, presence of a marigold band at the submarginal region, and larger pointed forewings. Distinguished from visually similar E. chalcedona by male genitalia structure. Antennae clubs are yellow with black bases. Brown compound eyes differentiate it from other Nymphalidae. At higher elevations, individuals are noticeably darker.

Occurs across diverse elevations and environments including mountain summits, grasslands, canyons, and dry conifer forests. Alpine and subalpine populations studied at elevations up to 3700 m in Colorado.

Mid to western North America: north to Yukon and British Columbia, east to Manitoba, south to New Mexico and Arizona.

Adult flight occurs once annually from late May to mid-August, timing varying with elevation and geographic range.

Larvae are herbivores feeding on plants containing iridoid glycosides, including Besseya alpina, B. plantaginea, and Castilleja integra. Diet varies by available local vegetation. Adults are nectarivores, feeding from flowers including penstemon and dogbane; adult males also visit mud puddles.

• Besseya alpina - larval host plantsource of catalpol and aucubin
• Besseya plantaginea - larval host plantsource of catalpol esters and catalpol
• Castilleja integra - larval host plantsource of macfadienoside and catalpol
• Plantago erecta - larval host plant
• Symphoricarpos - larval host plant

Females produce 2–3 egg clusters hidden under host plant leaves; eggs hatch after approximately two weeks. Larvae construct silk shelters over host plants for protection, remaining until winter or host plant defoliation. Larvae enter diapause after the third or fourth molt, typically beginning early autumn. Diapause duration varies with environmental conditions and can extend multiple years. Pupation occurs after 3–4 additional molts following diapause termination. Caterpillar mortality rate is approximately 98%.

Non-migratory species. Adults show greater movement distances than most Euphydryas populations and other alpine Euphydryas populations, with movement patterns similar to E. chalcedona and more vagile E. editha populations. Female distribution is influenced by host-plant density and male harassment.

Larvae sequester iridoid glycosides from host plants, retaining these chemical defenses throughout life. These compounds serve as unpalatability signals to predators, supported by aposematic coloration.

The cloudcrofti subspecies (Euphydryas anicia cloudcrofti) is listed as endangered by the U.S. Fish and Wildlife Service due to climate change, construction, and invasive plants. The species is globally ranked G5 (secure), though some populations in southern Canada are considered vulnerable (G3) to critically imperiled (G1).

• Euphydryas edithaDiffers by presence of white spots on abdomen, lacking marigold submarginal band, and smaller less pointed forewings
• Euphydryas gillettiiDiffers by presence of white spots on abdomen, lacking marigold submarginal band, and smaller less pointed forewings
• Euphydryas chalcedonaVisually similar; reliable distinction requires examination of male genitalia

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Mantispidae | Beetles In The Bush
• July | 2024 | Beetles In The Bush
• Mating Behavior and Male Investment in Euphydryas anicia (Lepidoptera: Nymphalidae)
• The ecology and population genetics of an alpine checkerspot butterfly, Euphydryas anicia
• Euphydryas anicia (Lepidoptera: Nymphalidae) utilization of iridoid glycosides fromCastilleja andBesseya (Scrophulariaceae) host plants
• Host Plant Suitability in a Specialist Herbivore, Euphydryas anicia (Nymphalidae): Preference, Performance and Sequestration
• Influence of host-plant density and male harassment on the distribution of female Euphydryas anicia (Nymphalidae)
• Observations of late instar larva survival of Cotesia (Hymenoptera: Braconidae) parasitoid attack of Euphydryas anicia cloudcrofti (Lepidoptera: Nymphalidae)