Coastal Silver-stiletto vs large tortoiseshell

Acrosathe annulata compared with Nymphalis polychloros

Key Differences

• Coastal Silver-stiletto is Least Concern while large tortoiseshell is Critically Endangered.

Taxonomic Classification

Rank	Coastal Silver-stiletto	large tortoiseshell
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Arthropoda (Arthropods)	Arthropoda (Arthropods)
Class same	Insecta (Insects)	Insecta (Insects)
Order	Diptera (Diptera)	Lepidoptera (Butterflies & Moths)
Family	Therevidae	Nymphalidae (Brush-footed Butterflies)
Genus	Acrosathe	Nymphalis
Species	Acrosathe annulata	Nymphalis polychloros

Evolutionary Relationship

Coastal Silver-stiletto and large tortoiseshell share a common ancestor at the Class level: Insecta. (Insects)

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

large tortoiseshell

CR — Critically Endangered

Physical Characteristics

Attribute	Coastal Silver-stiletto	large tortoiseshell
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

large tortoiseshell

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 9 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Europe (39 countries). Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Coastal Silver-stiletto

Coastal silver stiletto (Acrosathe annulata) is a slender robber fly in the family Therevidae, native to northwestern Europe, including the United Kingdom, France, the Netherlands, Belgium, and Scandinavia. Adults are found on coastal sand dunes and sandy heathland, where they perch on bare sand to ambush small flying insects. Stiletto flies in the family Therevidae are characterised by a slender body, long pointed abdomen, and predatory habits; adults prey on a variety of small dipterans and other flying insects during warm, sunny periods. Larvae develop in sandy soil, where they are also predatory, feeding on other invertebrate larvae. Acrosathe annulata is a habitat specialist restricted to open, sandy coastal habitats with sparse vegetation—environments that have declined substantially across northwestern Europe due to dune stabilisation, recreational disturbance, and the cessation of traditional dune management. The IUCN lists it as Least Concern, though regional conservation bodies in the United Kingdom have flagged population declines. It is considered an indicator of high-quality coastal sand dune habitats and is monitored through national invertebrate surveys.

large tortoiseshell

large tortoiseshell (Nymphalis polychloros) is classified as Critically Endangered (CR) on the IUCN Red List. Facing an extremely high risk of extinction in the wild due to severe population decline and habitat loss.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden