California alder vs Common Red-legged Robberfly

Alnus rhombifolia compared with Dioctria rufipes

Taxonomic Classification

Rank	California alder	Common Red-legged Robberfly
Kingdom	Plantae (植物)	Animalia (動物)
Phylum	Magnoliophyta (被子植物門)	Arthropoda (節足動物)
Class	Magnoliopsida (モクレン綱)	Insecta (昆虫)
Order	Fagales (ブナ目)	Diptera (ハエ目)
Family	Betulaceae	Asilidae
Genus	Alnus	Dioctria
Species	Alnus rhombifolia	Dioctria rufipes

Conservation Status

California alder

LC — Least Concern

Common Red-legged Robberfly

LC — Least Concern

Physical Characteristics

Attribute	California alder	Common Red-legged Robberfly
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

California alder

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Found in Canada.

Common Red-legged Robberfly

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

California alder

The California alder (Alnus rhombifolia) is a species in the genus Alnus. It is currently classified as Least Concern on the IUCN Red List. Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Common Red-legged Robberfly

<em>Dioctria rufipes</em>, the common red-legged robberfly, is a predatory fly in the family Asilidae, order Diptera. It is distributed across northwestern Europe, with confirmed records from Belgium, Denmark, Norway, and Sweden, typically favoring woodland edges, hedgerows, and meadows with abundant vegetation. The species is assessed as Least Concern on the IUCN Red List, reflecting stable populations across its European range. Robberflies in the genus Dioctria are slender, elongated flies characterized by a distinctive long proboscis used to inject paralyzing saliva into prey. <em>Dioctria rufipes</em> typically hunts smaller flying insects, including midges, small flies, and other soft-bodied arthropods, ambushing prey from resting perches on vegetation and capturing it mid-flight. Adults are typically active from late spring to early autumn, coinciding with peak insect activity. The red or reddish-orange coloration of the hind femora is the diagnostic feature that gives this species its common name. Larvae develop in soil or decaying wood, where they are believed to be predatory on other invertebrate larvae. Biological traits such as precise lifespan, body measurements, and diet composition remain poorly documented in quantitative studies. The species is considered an important component of invertebrate predator guilds in European agricultural landscapes.