Pollination in Lilium sargentiae (Liliaceae) and the first confirmation of long-tongued hawkmoths as a pollinator niche in Asia

摘要

The geographical distribution of pollinators is an important factor determining the biogeographical pattern of floral evolution and diversification.In Africa,a guild of plant species has converged in a floral syndrome for pollination by long-tongued hawkmoths (predominantly Agrius convolvuli).It is hypothesized that such floral convergence could track the geographical distribution of long-tongued hawkmoths,so it may not be confined to Africa.We investigated the pollination biology of Lilium sargentiae E.H.Wilson,which is endemic to China and exhibits traits suggestive of long-tongued hawkmoth pollination.Lilium sargentiae was visited by A.convolvuli as well as small beetles (Nitidulidae) but pollination was mostly or totally effected by the moth.It was consistent with other hawkmoth-pollinated plants in terms of floral tube length,nectar traits,tepal reflectance,and scent composition.We present the first experimental evidence for the hypothesis proposed above and for hawkmoth pollination in the widespread and ornamentally and economically important genus Lilium L.in a natural habitat.Our findings imply that long-tongued hawkmoths (especially the extremely widespread A.convolvuli) as a distinctive pollinator niche may have underlain the evolution of long-tubed (＞8 cm) flowers across different continents.