Floral display and pollination success in Senecio jacobaea (Asteraceae) : Interactive effects of head and corymb size

摘要: The self-sterile Senecio jacobaea (Asteraceae) presents its rayed heads in large, compound inflorescences (corymbs). I examined the role of head and corymb size pollinator attraction, whether positive effect intact rays (if any) depends on corymb. Using female fertility as a measure pollination success, assessed performance stems representing four experimentally produced character combinations: (1) few without rays, (2) many (3) with (4) rays. proportion flowers setting fruit was higher for (treatments 2, 4) than which majority had been removed 1, 3), suggesting selection maximum inflorescence production. By contrast, experimental removal all relatively weak negative set, few-headed (treatment 1) experiencing greater reduction 2). These results suggest that clusters produce synergistic allowing plants to maintain high visitation rates even if there are drastic reductions basic attraction units. Hence, number attractiveness individual interacted their success. Fruit set per flower differed greatly between sites positively correlated plant density.