none The biology and life-history of Olibrus aeneus Fab. (Col., Phalacridae), a species feeding on the seeds and receptacle of Tripleurospermum perforatum (Merat) Wagenitz and some other Anthemideae, is described. Detailed information is given on its oviposition behaviour, the distribution of attack and resource utilization. The oviposition period of O. aeneus lasts for 6-8 weeks, and a comparatively broad range of developmental flowerhead stages is accepted. On average O. aeneus attacks 40% of the flowerheads available per plant population (range: 10% to 52%). At the main sampling sites, flowerheads attacked by O. aeneus contained on average 1.4 (Bayreuth) to 1.9 (Kiel) larvae per head. Apical flowerheads were attacked to a significantly higher degree than non apical heads. Finally, the potential of O. aeneus for the biological control of T. perforatum is discussed. Nutrition; Diet; Reproduction; Reproductive behaviour; Life cycle and development; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Land and freshwater zones; Palaearctic region; Europe Olibrus aeneus (Phalacridae); Food plants; Anthemideae; Biology; Egg laying; Food plant use, patterns & timing; Life cycle and development; Hymenopteran parasites; Glabrobracon anthracinus; Note; Distribution within habitat; Ovipositional distribution in food plants; Germany & Hungary; Germany; North & south; Hungary; South east; Biology & food plant resource use Glabrobracon anthracinus (Braconidae); Coleopteran hosts; Olibrus aeneus; Note; Germany & Hungary; Germany; North & south; Hungary; South east; Recorded from coleopteran host & host biology