Common Flat-body vs Common Red-legged Robberfly

Agonopterix heracliana compared with Dioctria rufipes

Taxonomic Classification

Rank	Common Flat-body	Common Red-legged Robberfly
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Arthropoda (Arthropods)	Arthropoda (Arthropods)
Class same	Insecta (Insects)	Insecta (Insects)
Order	Lepidoptera (Butterflies & Moths)	Diptera (Diptera)
Family	Depressariidae	Asilidae
Genus	Agonopterix	Dioctria
Species	Agonopterix heracliana	Dioctria rufipes

Evolutionary Relationship

Common Flat-body and Common Red-legged Robberfly share a common ancestor at the Class level: Insecta. (Insects)

Conservation Status

Common Flat-body

LC — Least Concern

Common Red-legged Robberfly

LC — Least Concern

Physical Characteristics

Attribute	Common Flat-body	Common Red-legged Robberfly
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Flat-body

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Common Red-legged Robberfly

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Common Flat-body

<em>Agonopterix heracliana</em> is a moth belonging to the family Depressariidae within the order Lepidoptera. Commonly known as the common flat-body, this species is named for the flattened resting posture characteristic of the genus Agonopterix. The species is classified as Least Concern on the IUCN Red List, with no indication of significant population decline. <em>Agonopterix heracliana</em> is distributed across northwestern Europe, with documented occurrences in Belgium, Denmark, Norway, and Sweden. Larvae of this species are typically associated with plants in the family Apiaceae, particularly hogweed (Heracleum sphondylium) and related umbellifers, upon which they feed while sheltering in rolled or folded leaves. Adults are typically brownish with subtle markings and are active from late summer through winter and early spring, overwintering as adults — an unusual life history trait among moths. The species inhabits hedgerows, woodland margins, and meadows where its host plants are abundant. Biological traits of this species remain poorly documented in the scientific literature.

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.

Shared Countries

Both species can be found in 4 countries:

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