Flower visitor fauna of the narrow endemic lily Lilium rubellum Baker in a lowland habitat in Yamagata, northern Japan

摘要

Floral visitor fauna of the narrow endemic lily Lilium rubellum was examined in a lowland habitat in Kaminoyama City, Yamagata Prefecture, northern Japan. Flowers of L. rubellum bloomed from early to late June. During 23 h of observing floral visitors, 64 insects were detected on L. rubellum flowers. Although coleopteran insects were most frequently found on L. rubellum flowers, they did not seem to be effective pollinators because of their body size. Bees were less frequently observed than coleopteran insects, but all individuals contacted sexual organs in L. rubellum flowers. Syrphid flies were seen less frequently, but they were also considered effective pollinators. From our observations, L. rubellum is a bee-pollinated species of the genus Lilium. Bee pollination has also been recorded in a species of Lilium sect. Archelirion, L. japonicum var. abeanum. The floral characteristics of L. japonicum var. abeanum (e.g., pinkish color, relatively small and tubular corolla, and lateral insertion of anthers into the corolla) were similar to those of L. rubellum and the character combination may be related to the bee-pollination mode in Lilium. key words： bee pollination, Bombus, Ceratina, flower visitor fauna, Lilium japonicum var. abeanum, Lilium rubellum, nitidulid beetle, syrphid fly