Flowering, pollen characteristics and insect foraging on Campanula bononiensis (Campanulaceae), a protected species in Poland
This study investigated the floral biology and pollen quantity and quality of <em>Campanula bononiensis </em>L. (Campanulaceae), a protected species in Poland. Observations and measurements were made during the years 2007–2009 in natural phytocoenoses from the Festuco-Brometea class situated within the Lublin area, SE Poland. A considerable decrease (approx. 87%) in population density was observed. Significant variations both in the amount of pollen (18.5%–34.8% of pollen in the total anther dry weight, i.e. 0.5–1.5 mg per 10 anthers) and in pollen viability (38.8–97.0%) were noted. Both a low amount of pollen and low pollen viability may reduce the reproductive success of individuals. The most frequent visiting insects were bees (<em>Apoidea</em>), including solitary bees 45.7%, honeybees 20.4%, and bumblebees 11.4%. Dipterans, coleopterans (weevils), lepidopterans and ants were also recorded, implying a strong impact of <em>C. bononiensis </em>on insect biodiversity within grasslands.