The roles of phenology and reward structure in the pollination biology of wild sunflower (Helianthus annuus L., Asteraceae).

摘要: ABSTRACT A seven-year study of Helianthus annuus L., the common sunflower, in its native range Texas has shown that phenology and reward production schedules individual florets within a head are paramount importance determining foraging behavior both specialist generalist bees serve as pollinators. Both pollen nectar produced only during male phase protandrous disk florets, but is bimodally whereas sugar accumulation constant. Acceptance heads by was positively correlated with number male-phase per head, although approaches not. Native responded to increases amounts, determined experiments using bagged which accumulated, increasing time spent floret. Comparisons across an array visitors showed large were more effective pollinators than small bees, bee category, there no differences...