Aradus crenatus

Crenulated Flat Bug

Aradus crenatus, Crenulated Flat Bug under bark


Family: Aradidae

Subfamily: Aradinae

Length: 8 - 11 mm


Worldwide there are about 200 described species in the genus Aradus. Most if not all feed on fungi—threads of fungi found under dead bark, for example. About half a dozen species show a preference for burned over areas, where they feed on the fungi that colonizes burnt wood. In several of these species researchers have found infrared receptors that may help the bug locate fires (Schmitz, Schätzel, and Schmitz, 2010).

Here are some of the important traits of the genus: the upper surfaces are granulate to rough; the antenniferous tubercles each forms a spine. The eyes project outward; the pronotum is usually reflexed, and is always wider than long. The pronotum bears six ridges, the outer two less noticeable than the others. The scutellum is long and triangular, or occasionally pentagonal. The thickened portion of hemelytra is short. The exposed connexivum is noticeably broad. In some species there are brachypterous forms.

Aradidae: Aradus crenatus, Flat Bug photo from West Virginia


Aradus crenatus is recognized by its scalloped sides and posterior edges. It is one of the largest members of the family in eastern North America.

The range of this species is indicated on the map below.  Interestingly, the species has been recorded from Mexico, but not from any U.S. state contiguous to Mexico.


Head of Aradus crenulatus, lateral view, Aradidae

Range map, Aradus crenatus, family Aradidae

A note about our maps

American Insects site