Coastal Silver-stiletto vs Common Bladder Moss

Acrosathe annulata compared with Physcomitrium pyriforme

Taxonomic Classification

Rank	Coastal Silver-stiletto	Common Bladder Moss
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Bryophyta
Class	Insecta (Insects)	Bryopsida (Bryopsida)
Order	Diptera (Diptera)	Funariales (Funariales)
Family	Therevidae	Funariaceae
Genus	Acrosathe	Physcomitrium
Species	Acrosathe annulata	Physcomitrium pyriforme

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

Common Bladder Moss

LC — Least Concern

Physical Characteristics

Attribute	Coastal Silver-stiletto	Common Bladder Moss
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 Bladder Moss

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Luxembourg, Portugal, 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 Bladder Moss

The common bladder moss (<em>Physcomitrium pyriforme</em>) is a small annual moss belonging to the family Funariaceae. It is classified as Least Concern on the IUCN Red List and is native to Europe and North America, with confirmed records from Luxembourg, Portugal, and the United States. <em>Physcomitrium pyriforme</em> typically colonizes disturbed, moist soils such as cultivated fields, riverbanks, and pond margins, where it forms low-growing green mats or cushions. The species is an ephemeral moss, completing its life cycle rapidly after disturbance events that expose bare soil. It is recognizable by its pear-shaped or inflated capsules borne on short setae, which give the species its common name. Spores are dispersed through the splitting of the capsule lid, and the plant often takes advantage of temporarily wet conditions for growth and reproduction. Biological traits of this species remain poorly documented in the scientific literature.