arrowhead vs Coastal Silver-stiletto

Sagittaria sagittifolia compared with Acrosathe annulata

Taxonomic Classification

Rank	arrowhead	Coastal Silver-stiletto
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Arthropoda (Arthropods)
Class	Liliopsida (Monocots)	Insecta (Insects)
Order	Alismatales (Alismatales)	Diptera (Diptera)
Family	Alismataceae	Therevidae
Genus	Sagittaria	Acrosathe
Species	Sagittaria sagittifolia	Acrosathe annulata

Conservation Status

arrowhead

LC — Least Concern

Coastal Silver-stiletto

LC — Least Concern

Physical Characteristics

Attribute	arrowhead	Coastal Silver-stiletto
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

arrowhead

Habitat

Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Oceanian biogeographic realm.

Range

Widely distributed across Asia (India), Europe (7 countries), North America (Mexico), and Oceania and the Pacific (Australia, Fiji).

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

arrowhead

The Arrowhead, Sagittaria sagittifolia, is a species. It is currently assessed as least concern on the IUCN Red List. Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Oceanian biogeographic realm.

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.