Coastal Silver-stiletto vs Common Ectemnius

Acrosathe annulata compared with Ectemnius continuus

Taxonomic Classification

Rank	Coastal Silver-stiletto	Common Ectemnius
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Arthropoda (Arthropods)	Arthropoda (Arthropods)
Class same	Insecta (Insects)	Insecta (Insects)
Order	Diptera (Diptera)	Hymenoptera (Ants, Bees & Wasps)
Family	Therevidae	Crabronidae
Genus	Acrosathe	Ectemnius
Species	Acrosathe annulata	Ectemnius continuus

Evolutionary Relationship

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

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

Common Ectemnius

LC — Least Concern

Physical Characteristics

Attribute	Coastal Silver-stiletto	Common Ectemnius
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.

Common Ectemnius

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, Sweden, and United States.

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.

Common Ectemnius

<em>Ectemnius continuus</em>, the common ectemnius, is a solitary predatory wasp in the family Crabronidae, classified as Least Concern by the IUCN Red List. The species is documented in Belgium, Denmark, Norway, Sweden, and the United States, occurring across virtually all terrestrial and freshwater biome types within its range. <em>Ectemnius continuus</em> is a wood-nesting wasp that typically excavates nest galleries in dead or decaying wood, including logs, stumps, and structural timber, where females provision individual brood cells with paralyzed flies as larval food. The adult wasps are diurnal and can often be observed at flowers, consuming nectar as a fuel source, or hunting flies in sunlit forest edges, hedgerows, and gardens. Females are capable hunters, pursuing and paralyzing dipteran prey in flight before carrying them back to the nest. As predators of flies, crabronid wasps like <em>Ectemnius continuus</em> contribute to the natural regulation of fly populations in temperate ecosystems. The species is part of a diverse guild of cavity-nesting aculeate hymenoptera that occupies dead wood habitats, making dead wood retention in forests ecologically important for their conservation. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 4 countries:

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