Olibrus bullatus
(Fabricius, 1792)
Olibrus bullatus is a small in the Phalacridae, commonly known as the shining flower beetles. It is a widespread European associated with grassland and meadow . The species has been recorded feeding on pollen and fungal spores, particularly those of grasses and sedges. are active during the spring and summer months.
Pronunciation
How to pronounce Olibrus bullatus: /oʊˈlaɪbrʊs bʊˈleɪtəs/
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Identification
The strongly convex, almost hemispherical body shape distinguishes Olibrus bullatus from most other small beetles in similar . The combination of small size (<3 mm), smooth and shiny without , and the domed profile separates it from members of such as Corylophidae or small Cerylonidae. Within Phalacridae, O. bullatus is larger and more convex than Olibrus aeneus, which is flatter and more elongate-oval. The similar Phalacrus substriatus has distinct elytral striae and a less convex body.
Appearance
Small, oval, and highly convex , 1.5–2.5 mm in length. Body distinctly domed, giving a rounded, almost spherical profile when viewed from the side. smooth, shiny, and dark brown to black, often with a slight metallic luster. short with a weakly clubbed tip. Legs relatively short and pale in color. Pronotum broad, covering much of the from above.
Habitat
Grasslands, meadows, and pastures, particularly those with abundant flowering grasses and sedges. Frequently found in the flower of Poaceae and Cyperaceae. Occurs in both dry and moist grassland situations, including coastal dunes and inland flood meadows.
Distribution
Widespread across Europe, from the British Isles and Scandinavia south to the Mediterranean, and east to Russia. Records extend from lowland to montane elevations up to approximately 1500 m. Absent from Macaronesia.
Seasonality
active from April to September, with peak abundance in May–June. stage unknown but likely as adults based on related .
Diet
Pollen of grasses (Poaceae) and sedges (Cyperaceae); fungal spores, particularly smuts (Ustilaginaceae) infecting grass inflorescences.
Host Associations
- Poaceae - pollen/flower feeding frequent grass flower
- Cyperaceae - pollen/flower feeding frequent sedge inflorescences
- Ustilaginaceae - spore feedingconsumes smut fungi on grasses
Life Cycle
Larval development has been observed within grass flower and in association with smut fungi. Complete details are poorly documented; larvae likely feed on fungal material within inflorescences. occurs in situ within flower heads or in soil.
Behavior
climb grass stems to reach inflorescences, where they remain for extended periods feeding on pollen. When disturbed, they drop to the ground and may feign death. Strong fliers, capable of dispersing between grassland patches.
Ecological Role
Pollen consumer and potential minor of grasses. Mycophagous habits may contribute to regulation of smut fungal in grass .
Human Relevance
No direct economic significance. Occasionally collected in agricultural grasslands but not considered a pest. Presence may indicate structurally diverse, flower-rich grassland .
Similar Taxa
- Olibrus aeneusFlatter, more elongate-oval body; less convex profile; often with bronze or greenish metallic coloration
- Phalacrus substriatusDistinct elytral and less convex body; more elongate overall form
- Corylophidae (minute hooded beetles)Similar size but with hooded pronotum covering and often with visible elytral punctation or setae