Coastal Silver-stiletto vs

Acrosathe annulata compared with Hydropus trichoderma

Key Differences

Coastal Silver-stiletto is Least Concern while is Endangered.

Taxonomic Classification

Rank	Coastal Silver-stiletto
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Arthropoda (Arthropods)	Basidiomycota (Club Fungi)
Class	Insecta (Insects)	Agaricomycetes (Mushrooms)
Order	Diptera (Diptera)	Agaricales (Gilled Mushrooms)
Family	Therevidae	Mycenaceae
Genus	Acrosathe	Hydropus
Species	Acrosathe annulata	Hydropus trichoderma

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

EN — Endangered

Physical Characteristics

Attribute	Coastal Silver-stiletto
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.

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Distributed across Denmark, Norway, and Sweden. Currently classified as 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.

Hydropus trichoderma is a small, saprotrophic mushroom with a delicate, slender stipe and a pale, convex cap that grows on decaying woody debris in forest habitats. It is recorded from temperate European forests and contributes to wood decomposition in woodland ecosystems. Its Endangered status reflects rarity and the decline of undisturbed, mature forest with adequate deadwood.