Small-eyed flour beetle.

Palorus ratzeburgii (Wissmann), the small‑eyed flour beetle, is a minute reddish‑brown tenebrionid. Adults measure 2.4–3.0 mm, with compound eyes entire and not bisected by the lateral margin of the head—a key diagnostic character among stored‑product beetles. Larvae are cylindrical and pale brown. This species is among the smallest Tenebrionidae associated with stored commodities.

Damage in stored grain is non-diagnostic. Both adults and larvae attack commodities. As a secondary stored‑product pest, it exploits cracked kernels and processed fractions (flour, bran, semolina), rasping the endosperm and germ and generating fines and dust that reduce test weight. In already compromised kernels it may create shallow feeding scars, further weakening grain integrity. Lots become contaminated with frass, exuviae, and dead insects, increasing dockage and lowering grade. Aggregations can produce localized heating and moisture pockets, encouraging mold growth, caking, and off‑odors. Activity concentrates in residues along floors, seams, and packaging, enabling rapid spread and re‑infestation. The overall impact is quality downgrade, reduced milling yield, and diminished marketability—injuries that are typical of secondary tenebrionid infestations and not distinctive from those of similar beetles.

Indicators of the Small-eyed flour beetle, Palorus ratzeburgii (Wissmann), in stored grain: - Persistent unpleasant, musty odor from infested lots. - Presence of adults and larvae in probe samples, concentrated in fines and along bin walls. - Powdery frass and feeding dust; meal-like accumulations beneath spouts and on surface crusts. - Damaged kernels: perforations, hollowed interiors, abraded germ/endosperm, and patchy discoloration. - Cast skins (exuviae), head capsules, and dead beetles intermixed with grain. Early detection of these signs helps prevent quality loss and off-odors in stored commodities.

Palorus ratzeburgii (Wissmann), the small‑eyed flour beetle, undergoes complete metamorphosis: egg → larva → pupa → adult. After mating, females oviposit among stored commodities. The eggs are adhesive and quickly become coated with flour or cereal dust, camouflaging them in the food substrate. Neonate larvae eclose and move freely through the bulk, feeding and developing within the commodity. After several larval instars, they pupate in the same material. Newly eclosed adults emerge, disperse within the lot, and resume reproduction. All stages remain concealed, enabling overlapping generations that steadily damage stored grain and processed cereals.

Prefers warm, humid, moldy microhabitats in stored cereals. A mycetophagous detritivore, it prospers in damp residues, dust and caked grain, especially alongside Sitophilus weevils, feeding on their frass and associated fungal growth.

Broad-horned flour beetle (Gnatocerus cornutus) Species of the genus Latheticus Species of the genus Tribolium