Silvaninae

Distinguished from other silvanid subfamilies by the combination of dorsoventral flattening, three-segmented antennal club, and five-segmented tarsi. The genus *Oryzaephilus* (sawtoothed grain beetle and merchant grain beetle) is recognized by the six sawtoothed projections on each side of the pronotum. *Cathartus* species lack these pronounced teeth and have more rounded body contours. Separation from Cucujidae (cucujid bark beetles) requires examination of antennal structure and tarsal segmentation.

Body dorsoventrally flattened, elongated to oval in shape. Antennae with distinct three-segmented club. Pronotum with lateral margins often expanded or toothed. Elytra typically parallel-sided, completely covering the abdomen. Tarsi with five segments on all legs. Body length generally 2–6 mm. Coloration variable, ranging from pale brown to dark brown or black.

Primarily associated with dead or decaying wood, occurring under loose bark of trees and in fallen logs. Several species have adapted to human-modified environments, inhabiting stored grain, dried fruit, and other food products. Forest habitats span both temperate and tropical regions.

Cosmopolitan distribution. Native ranges encompass North America, South America, Europe, Africa, Asia, and Australasia. Human-mediated dispersal has established several species worldwide as stored product pests.

Many species are mycophagous or saprophagous, feeding on fungal hyphae and decaying plant matter under bark. Several species in *Oryzaephilus*, *Cathartus*, and *Ahasverus* are significant pests of stored products, feeding on grain, cereals, dried fruit, nuts, and chocolate.

Complete metamorphosis with egg, larval, pupal, and adult stages. Larvae are elongate, cylindrical, and mobile. Developmental rates vary by species and temperature; stored product pests can complete multiple generations annually under favorable conditions. Pupation typically occurs in sheltered locations within the substrate.

Adults and larvae are agile and fast-moving. When disturbed, adults often adopt a death-feigning posture or seek tight crevices. Stored product species demonstrate strong positive thigmotaxis, aggregating in cracks and corners of storage containers. Some species are capable of flight and are attracted to light.

Decomposers in forest ecosystems, contributing to nutrient cycling through consumption of fungi and decaying wood. In stored product environments, species act as primary or secondary pests, facilitating spoilage and providing food for other arthropod pests.

Several species are major stored product pests causing significant economic losses. *Oryzaephilus surinamensis* (sawtoothed grain beetle) and *Oryzaephilus mercator* (merchant grain beetle) are among the most economically important pests of grain, cereals, and processed foods globally. *Cathartus quadricollis* (square-necked grain beetle) and *Ahasverus advena* (foreign grain beetle) are also significant pests. Control relies on sanitation, proper storage, and fumigation.

• BrontinaeOther subfamily of Silvanidae; distinguished by different antennal structure and less pronounced body flattening in many species
• CucujidaeFamily of flat bark beetles with similar flattened habitus; separated by antennal club segmentation and other mouthpart characters

• Coleoptera
• Silvanidae
• stored product pest
• bark beetle
• mycophagous
• decomposer

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life